Method and device for the cosmetic treatment of keratin fibres

Abstract

Hair treatment device (20) for treating at least one lock of hair to be treated, comprising a member (26) for emitting at least one treatment agent from the group comprising an artificial electromagnetic radiation light source or a heat source. The hair treatment device (20) comprises: - a motion detection unit configured to detect a relative movement between the treatment device (20) and the lock of hair to be treated and comprising at least one photodetector (27) configured to perceive a luminosity and to generate at least one current value on the basis of the luminosity perceived; and - a signal processing unit (29) configured to read current values transmitted by the photodetector (27) and to deduce movement information therefrom on the basis of a current variation; and an electronic control unit (ECU) configured to determine a control signal from the movement information in order to control the member (26) for emitting at least one treatment agent.

Description

[0001] DESCRIPTION

[0002] TITLE: Method and device for the cosmetic treatment of keratin fibres

[0003] The present invention relates to the field of devices for treating keratin fibres, in particular a user’s hair.

[0004] More particularly, the invention relates to the cosmetic treatment of keratin fibres.

[0005] A “cosmetic product” is understood, in particular within the meaning of the present invention, to be a product as defined in Regulation (EC) No 1223 / 2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products.

[0006] It is known practice to use appliances for shaping hair, in particular for hair relaxing and / or straightening operations.

[0007] Hair treatment devices comprising a heating member having a heating element with or without steam and that enables a lock of hair to be shaped are known.

[0008] Hair “brush” type hair treatment devices are known.

[0009] The heating treatment surface may or may not be associated with the emission of steam.

[0010] Generally, such treatment devices comprise temperature sensors for preventing damage to the hair.

[0011] Reference may be made in this respect to document WO 2023 / 001980 - Al, which proposes a hair treatment device in the form of a brush, in particular having a heating treatment surface and / or diffusing steam.

[0012] Furthermore, in order to enable durable shaping of the head of hair, such brushes may be accompanied by the implementation of a treatment by a composition based on active chemical agents.

[0013] Such brushes may also comprise a heating member.

[0014] Document WO 2014 / 111646 - Al, which proposes a hair-styling device comprising an accelerometer configured to measure the movements of the hair-styling operation, is known. However, the sensitivity of accelerometers is very low and requires large, rapid movements, and they do not enable almost constant movements to be detected.

[0015] It is also known practice to treat hair using electromagnetic radiation. Reference may be made in particular to document FR 2 941 600 - Al, which proposes a hair treatment method in which the keratin fibres are exposed to infrared radiation.

[0016] However, in hair treatment devices implementing heat or electromagnetic radiation, the risk of bums or of interaction with the electromagnetic radiation is high and it is necessary to be able to control the exposure in terms of time and / or power. There is therefore a need to improve the safety of hair treatment devices implementing heat or electromagnetic radiation.

[0017] Another object of the invention is to reduce the electrical consumption of the hair treatment device.

[0018] The invention relates to a hair treatment device for treating at least one lock of hair to be treated, comprising a member for emitting at least one treatment agent from the group comprising an artificial electromagnetic radiation light source or a heat source.

[0019] The hair treatment device comprises:

[0020] - a motion detection unit configured to detect a relative movement between the treatment device and the lock of hair to be treated.

[0021] The detection unit comprises at least one photodetector configured to perceive a luminosity and to generate at least one current value, i.e. either a voltage or an intensity that depends on the resistivity in the case of a photoresistor, on the basis of the luminosity perceived.

[0022] The detection unit further comprises a signal processing unit configured to read current values transmitted by the photodetector and to deduce movement information therefrom on the basis of a variation in said current value read.

[0023] The hair treatment device further comprises an electronic control unit configured to determine a control signal from the movement information in order to control the member for emitting the one or more treatment agents.

[0024] More precisely, the signal processing unit is capable of determining whether the lock to be treated is moving relative to the treatment device when the lock is moved towards the treatment device, in particular when the lock is placed inside the treatment device, in particular in the case of a pair of tongs.

[0025] The device enables hair to be treated in a better controlled manner by limiting the unwanted risk of external emission of heat or of radiation outside the active treatment phase while at the same time limiting the electrical consumption.

[0026] In the known hair treatment devices comprising a conventional motion detector such as an accelerometer, the accelerometer is generally placed in the handle of the hair treatment device and therefore detects a movement of the handle without the lock of hair to be treated necessarily having been moved towards the device. Unlike known accelerometers, the photodetectors according to the invention make it possible to detect almost constant movements, and even movements of the hair when the hair treatment device is static.

[0027] The heat source may be a heating plate using thermal conductivity and / or a steam-emitting member. Advantageously, the signal processing unit is configured to detect the lock of hair being placed in contact with the treatment device when the variation in the current values transmitted by the photodetector is greater than or equal to a threshold value.

[0028] Said threshold value is between 6 nA per photodiode and 20 mA per photodiode in darkness, lower values being considered to relate to ambient noise.

[0029] A signal of less than 6 nA is considered to be ambient noise.

[0030] The signal processing unit is thus configured to determine one or more current variations on the basis of the current values transmitted by the photodetector.

[0031] A current “variation” is understood to be a difference between a first current value at a time t without hair nearby (starting t) and a second current value at a time t+1 or a series of current values at times t+1, t+2, . . . , t+n.

[0032] If the current variation is zero or almost zero between the single pair of values or between each pair (t, ti) of current values or between the first and last values (t, tn), there is no movement detected between the lock of hair and the treatment device. Conversely, if the current variation is not zero, and in particular greater than or equal to the threshold value, i.e. cannot be confused with noise, a movement between the lock of hair and the treatment device has been detected by the signal processing unit, thus implying the presence of the lock in the device.

[0033] This is in particular the case when the treatment device is in the form of a pair of tongs comprising two articulated arms, the arms moving together causing the passage from an environment with ambient light to an environment confined solely to the light of the treatment device.

[0034] Moreover, in the case of a pair of tongs, without a lock of hair, the current detected or the resistivity value is constant. In other words, there is no variation in the light perceived by the photodetector.

[0035] It has been observed that the movement of a lock of hair due to the natural irregularity of the fibres would cause a variation in the light perceived by the photodetector during the movement of the lock. Thus, by processing the electrical signal of the photodetector, it is possible to deduce therefrom information about the relative movement of the lock relative to the hair treatment device and thus about the presence of the lock of hair in the device.

[0036] The electronic control unit ECU is in particular configured to modify at least one treatment parameter, or even to stop the member for emitting a treatment agent if no relative movement between the treatment device and the lock of hair to be treated has been detected.

[0037] “Treatment parameter” of the member for emitting a treatment agent is understood to be the temperature and / or the luminous intensity as well as the flow rate when a fluid treatment agent such as steam is being used. Preferably, the artificial electromagnetic radiation light source is configured to emit ultraviolet-visible (UV-visible) radiation, infrared (IR) radiation, or microwaves.

[0038] For example, the artificial electromagnetic radiation light source comprises a plurality of light-emitting diodes (LEDs) configured to emit monochromatic ultraviolet-visible radiation with a wavelength of between 350 nm and 750 nm.

[0039] Preferably, the light-emitting diodes are directed radially towards the lock of hair.

[0040] Preferably, the photodetector is sensitive to UV-visible radiation.

[0041] The photodetector is thus sensitive to the variations in luminosity in the ultraviolet-visible radiation range.

[0042] For example, the heat source is configured to emit a temperature of less than or equal to 210°C.

[0043] According to one embodiment, the photodetector is a photosensitive component.

[0044] For example, the photodetector is a photoresistor, also known as a lightdependent resistor (LDR).

[0045] The photoresistor is an electronic component, the resistance value of which varies on the basis of the luminosity perceived.

[0046] The higher the luminosity, the lower its resistance value (resistivity). Conversely, the lower the luminosity, the greater its resistance value (resistivity).

[0047] The photoresistor comprises, for example, a support, for example made of ceramic, and two prongs or pins, with no polarity, for transmitting a current.

[0048] The surface of the photoresistor may be protected by an insulating resin or by a conventional lens or a lens filtering the ultraviolet radiation.

[0049] The photoresistor is an inexpensive component that is very easy to implement and has a very high sensitivity.

[0050] For example, the photodetector is a photodiode or a phototransistor.

[0051] In general, the photodetector is configured to generate a current on the basis of the luminosity.

[0052] According to a first embodiment, the hair treatment device is a hair brush.

[0053] A “brush” is understood to be a hair treatment device having a single arm bearing a plurality of teeth between which the hair is received as the brush passes through the head of hair. The brush may have a single row of teeth, in which case it is also referred to as a comb, or have a plurality of rows of teeth. The brush may comprise a heating treatment surface. The teeth may or may not also be actively heating.

[0054] The brush comprises a gripping portion and a treatment portion comprising a treatment surface and a plurality of teeth or protrusions that are arranged in a plurality of rows and extend from the treatment surface, the member for emitting a treatment agent being positioned on the treatment surface.

[0055] In one variant of the invention, the detection unit comprises a plurality of photodetectors. This makes it possible to ensure that the lock of hair is detected even if it does not cover the entirety of the treatment surface as the electromagnetic radiation light source.

[0056] The photodetectors may or may not be distributed uniformly over the head of the brush. They may be, for example, distributed equidistantly from one another.

[0057] For example, the member for emitting a treatment agent is integrated at the centre of the head of said brush.

[0058] For example, the photodetector is positioned on a side of said device in order to perceive the ambient light.

[0059] Advantageously, when the member for emitting a treatment agent comprises, for example by itself or in addition, a heat source, the treatment surface and / or the teeth may be heated by one or more heating elements electrically powered via an electrical wire to the mains or to a base station, or by batteries.

[0060] According to one embodiment, the hair treatment device further comprises an additional light source situated facing the photodetector.

[0061] Specifically, when the treatment agent comprises a heat source, the device may comprise an additional light source configured to illuminate the photodetector.

[0062] This is not absolutely necessary when the member for emitting a treatment agent comprises an electromagnetic radiation source that makes it possible to simultaneously treat the lock of hair and illuminate the photodetector.

[0063] According to a second embodiment, the treatment device is an iron, and preferably a straightening iron.

[0064] A “straightening iron” is understood to be a hair treatment device having two arms that are articulated relative to one another about a hinge and forming a pair of tongs that can move between a separated open position, advantageously in which a lock of hair to be treated may be positioned, and a closed configuration in which the lock of hair to be treated is in contact with the inner surfaces of said arms.

[0065] As a variant, provision could be made for the treatment device to comprise just one single arm.

[0066] The two arms are preferably articulated relative to one another using an articulation.

[0067] The two arms preferably extend along respective longitudinal axes.

[0068] For example, the two arms each comprise a gripping portion on which the user can press in order to move the two arms together into the closed position and a treatment portion situated at the end of the corresponding arm and each comprising a treatment surface, said treatment surfaces facing one another. A return member is preferably provided in order to exert a separating force between the arms without external loading from the user on said arms.

[0069] For example, the return member is a spring mounted around the articulation pin.

[0070] The treatment surfaces are, for example, in the form of a rectangular plate that is elongate along the respective longitudinal axes.

[0071] The movable arms define between them, with the treatment surfaces, a hair treatment region intended to receive a lock of hair to be treated, along which the treatment device is moved, for example in the direction from the root to the tip of the hair.

[0072] The direction of movement of the treatment device is preferably substantially perpendicular to the arms.

[0073] The electromagnetic radiation light source is, for example, integrated onto the treatment surface of one of the arms.

[0074] Advantageously, the one or more photodetectors are positioned on the same treatment surface as the electromagnetic radiation light source.

[0075] Preferably, the photodetector is positioned on a lateral edge of the treatment surface. Preferably, the photodetector is positioned on the treatment surface upstream of the light source in the direction of insertion and of passage of the lock of hair.

[0076] According to one embodiment, the hair treatment device comprises an additional light source, integrated onto the treatment surface of the other arm, facing the photodetector. The additional light source may be opposite the photodetector, but not necessarily since it is sufficient for incident radiation to arrive on the photodetector.

[0077] The photodetector and the electromagnetic radiation light source are preferably integrated onto two opposing treatment surfaces. In this case, it is no longer necessary to have the additional light source.

[0078] According to another embodiment, the member for emitting at least one treatment agent comprises a heat source and the device comprises an additional light source integrated onto the treatment surface of the other arm, facing the photodetector and configured to illuminate the photodetector, the device comprising one or more heating elements in the form of heating resistors configured to heat a treatment surface or the treatment surfaces, and electrically powered via an electrical wire to the mains or to a base station, or by non-rechargeable primary batteries or rechargeable secondary batteries.

[0079] In the case in which the treatment agent comprises a heat source, at least one arm, and preferably each arm, is equipped with a treatment surface in the form of a heating plate. During operations for treating a lock of hair, the latter is introduced between the two arms in the open position and then the two arms are closed manually over the lock of hair. The latter is then subjected, until the two arms are opened and the lock of hair is removed, to the heat output by the heating element, the appliance being able to be moved along the lock.

[0080] In one variant, the device may further comprise a steam-emitting member comprising a plurality of steam outlets opening onto at least one treatment surface.

[0081] The device makes it possible, in this case, to treat the hair while at the same time limiting the amount of water used, thereby reinforcing the autonomy of said device.

[0082] In another variant, the device may further comprise a member for emitting a cosmetic composition onto at least one treatment surface.

[0083] A shaping composition is understood to be a composition for curling, hairsetting, relaxing or straightening hair.

[0084] The cosmetic compositions comprise, for example, one or more active agents chosen from reducing agents, and in particular thiols, oxidizing agents and in particular hydrogen peroxide or persalts, such as persulfates, colouring agents such as pigments, direct dyes or oxidation dyes, temporary shaping agents such as styling polymers that are preferably anionic, amphoteric or nonionic, conditioning agents such as silicones, mineral or plant oils, plant waxes, cationic surfactants and cationic polymers, alkaline or acidic agents.

[0085] According to a second aspect, the invention relates to a hair treatment method for treating at least one lock of hair to be treated, comprising:

[0086] - a step of verifying the activation of a hair treatment device for treating at least one lock of hair to be treated, comprising:

[0087] - a member for emitting at least one treatment agent from the group comprising an artificial electromagnetic radiation light source or a heat source,

[0088] - a motion detection unit configured to detect a relative movement between the treatment device and the lock of hair to be treated and comprising at least one photodetector configured to perceive a luminosity and to generate at least one current value on the basis of the luminosity perceived and a signal processing unit configured to read the current values transmitted by the photodetector and to deduce movement information therefrom on the basis of a variation in said current value read; and

[0089] - an electronic control unit configured to determine a control signal from the movement information in order to control the member for emitting a treatment agent.

[0090] The method comprises:

[0091] - a step of switching on the member for emitting the one or more treatment agents;

[0092] - a step of reading the current values generated by the photodetector and received by the signal processing unit, of deducing movement information on the basis of a variation in said current value read and a control signal is determined from the movement information in order to control the member for emitting the one or more treatment agents; and

[0093] - a step of comparing the variation in said current values with a threshold value, which is considered, for example, to relate to ambient noise.

[0094] If the variation in the current values is greater than or equal to the threshold value, i.e. a movement between the lock of hair and the treatment device has been detected by the signal processing unit, thus implying the presence of the lock in the treatment device, the member for emitting the one or more treatment agents is triggered, for example either immediately or after a fixed latency.

[0095] “Movement information” distinguishes between the static or moving position, i.e. the variation in current or in resistivity.

[0096] If, before treatment or at the end of treatment, the variation in the current values relative to a time t without hair being present is less than the threshold value, i.e. there is no detected presence of the lock of hair, in a step, the duration for which said variation in the current values is less than the threshold value is compared with a time threshold value, and if said duration is greater than or equal to said time threshold value, in a step, the member for emitting a treatment agent is controlled in order to prevent the emission or to reduce its power to a safety value, or even to stop its power.

[0097] The variation in resistivity is connected to the current variation transmitted by the photodetector to the signal processing unit. In other words, in the case in which the photodetector is a photoresistor, if the variation in the resistivity values of the photoresistor is less than the threshold value, i.e. zero or almost zero, plus or minus the sensitivity of the component, and for the defined duration, the member for emitting a treatment agent is controlled by the electronic control unit in order to reduce or stop its power to ensure the user’s safety.

[0098] As a variant, it would be possible to consider the almost-zero slope received by the photodetector in the case of an empty pair of tongs, i.e. with no locks, to analyse a group of current values detected by the photodetector and received by the signal processing unit, and to compare said group of values with the almost-zero slope. If this group of values has a different slope to the almost-zero slope, it is considered that there is movement information and the treatment device is thus triggered either immediately or after a fixed latency.

[0099] The safety value for emission, in particular electromagnetic emission, may be between 0.5 W / cm2and 1.5 W / cm2for components having a peak wavelength at 385 nm.

[0100] The current threshold value is, for example, between 6 nA and 20 mA per photodiode, lower values being considered to relate to ambient noise.

[0101] A signal of less than 6 nA is considered to be ambient noise. Specifically, if the variation in the current values is greater than or equal to the threshold value, and therefore non-zero, this means that there has been a movement between the lock of hair to be treated and the treatment device. Conversely, if the variation in the current values is less than the threshold value, there has been no movement between the lock of hair to be treated and the treatment device.

[0102] The time threshold value is, for example, between 0.1 s and 5 s.

[0103] Preferably, if the variation in the time threshold values at the end of treatment is greater than or equal to the threshold value, the emission of the treatment is stopped.

[0104] If the duration is less than the time threshold value, the emission of the treatment is continued.

[0105] Activation may take place for example by connecting the appliance to the mains and / or by pressing an on switch present on the hair treatment device, for example on the gripping portion, in particular in the case of portable appliances equipped with primary or secondary batteries.

[0106] The treatment method may further comprise, in an entirely non-limiting manner, a step of applying a cosmetic composition, such as for example a composition for cleaning, dyeing, bleaching, conditioning, restoring or shaping hair.

[0107] The present invention will be better understood from studying the detailed description of embodiments, which are given by way of entirely non-limiting example and are illustrated by the appended drawings, in which:

[0108] [Fig i] is a schematic perspective view of a hair treatment device according to one embodiment of the invention;

[0109] [Fig.2] shows the device in Figure 1 according to another perspective;

[0110] [Fig-3] is a front view of a treatment surface of the device in Figure 1;

[0111] [Fig-4] is a schematic perspective view of a hair treatment device according to another embodiment of the invention; and

[0112] [Fig.5] shows a front view of the device in Figure 5.

[0113] [Fig.6] shows the steps of the hair treatment method according to the invention with the aid of the treatment device in Figure 1; and

[0114] [Fig.7A], [Fig.7B] and [Fig.7C] illustrate examples of signal processing on the basis of the movement along the lock of hair to be treated, of the time and of the tone depth of the lock of hair to be treated. A first example of a hair treatment device 10 is illustrated in Figures 1 to 3.

[0115] The treatment device has, in this case, the overall shape of a pair of tongs comprising two arms 11, 12 that can move relative to one another between a separated or open position in which a lock of hair to be treated may be positioned and a closed position in which the lock of hair to be treated is in contact with the inner surfaces I la, 12a of said arms 11, 12.

[0116] The two arms 11, 12 are articulated relative to one another using an articulation 13 or hinge.

[0117] The arms 11, 12 extend along respective longitudinal axes X, Y.

[0118] The two arms 11, 12 each comprise a gripping portion 1 lb, 12b on which the user can press in order to move the two arms together into the closed position.

[0119] A return member (not shown) is preferably provided in order to exert a separating force between the arms 11, 12 without external loading from the user on said arms.

[0120] For example, the return member is a spring mounted around the articulation pin 13.

[0121] Each arm 11, 12 comprises a treatment portion 11c, 12c situated at the end of the corresponding arm, said end being opposite the articulation 13.

[0122] Each treatment portion 11c, 12c comprises a treatment surface 14, 15. Said treatment surfaces 14, 15 face one another. In one variant, provision could be made for just one single treatment surface.

[0123] Said treatment surfaces 14, 15 are, this this case, in the form of a rectangular plate that is elongate along the respective longitudinal axes X, Y.

[0124] The arms 11, 12 define between them, with the treatment surfaces 14, 15, a hair treatment region intended to receive a lock of hair to be treated, along which the treatment device 10 is moved, for example in the direction from the root to the tip of the hair.

[0125] The direction of movement of the treatment device 10 is preferably substantially perpendicular to the arms 11, 12.

[0126] The hair treatment device 10 comprises a member 18 for emitting at least one treatment agent comprising, in this case, an artificial electromagnetic radiation light source.

[0127] As illustrated, the electromagnetic radiation light source 18 is integrated onto the treatment surface 14 of one of the arms 11.

[0128] As a variant, provision could be made for the electromagnetic radiation light source 18 to be integrated onto the treatment surface 15 of the other of the arms 12.

[0129] As illustrated in Figure 3, the hair treatment device 10 comprises a motion detection unit configured to detect a relative movement between a treatment device 10 and the lock of hair to be treated. The detection unit comprises at least one photodetector 17, in this case three photodetectors 17, configured to perceive a luminosity and to generate a current value.

[0130] More precisely, the photodetectors 17 are configured to generate a current characterized by either a voltage or an intensity that depends on the resistivity, on the basis of the luminosity perceived.

[0131] The detection unit further comprises a signal processing unit 19 configured to read the current values transmitted by the photodetector and to deduce movement information therefrom on the basis of a current variation.

[0132] The signal processing unit 19 can thus determine whether the lock to be treated is moving relative to the treatment device 10 or whether the treatment device 10 is moving relative to the lock to be treated, i.e. when the lock of hair is inserted into the treatment device 10.

[0133] “Movement information” distinguishes between the static or moving position, i.e. the current variation.

[0134] As illustrated, and in an entirely non-limiting manner, the photodetectors 17 are integrated onto the treatment surface 15 of one of the arms 12 and are distributed equidistantly from one another.

[0135] As illustrated, and in an entirely non-limiting manner, the photodetectors 17 and the electromagnetic radiation light source 18 are integrated onto two opposing treatment surfaces 14, 15. In other words, the photodetectors 17 are integrated onto the treatment surface 15 facing the electromagnetic radiation light source 18.

[0136] As a variant, provision could be made for the photodetectors 17 to be integrated onto the same treatment surface as the electromagnetic radiation light source 18. In this case, the treatment device 10 could comprise an additional light source (not shown), integrated onto the treatment surface 14 of the other arm 11, facing the photodetectors 17.

[0137] As a variant, provision could be made for the treatment member 18 to comprise a heat source. In this case, the treatment device 10 comprises an additional light source integrated onto the treatment surface 14 of the other arm 11, facing the photodetectors 17 and configured to illuminate the photodetectors 17.

[0138] For example, the heat source is configured to emit a temperature of between 90° and 250°C, preferably of between 120° and 250°C.

[0139] This is not absolutely necessary when the treatment agent comprises an electromagnetic radiation source that makes it possible to simultaneously treat the lock of hair and illuminate the photodetector.

[0140] For example, the photodetectors 17 are, in this case, centred on the treatment surface 15.

[0141] In the case in which the photodetectors 17 are integrated onto the same surface as the light source 18, the photodetectors 17 may be integrated onto a lateral edge of the treatment surface 15. In this case, the photodetector 17 is preferably integrated onto the treatment surface 15 upstream of the light source 18 in the direction of insertion and of passage of the lock of hair.

[0142] When the treatment agent comprises a heat source, the device 10 comprises one or more heating elements in the form of heating resistors configured to heat a treatment surface or the treatment surfaces 14, 15 and electrically powered via an electrical wire to the mains or to a base station, or by primary or secondary batteries.

[0143] The device 10 enables hair to be treated in a controlled manner by limiting the unwanted risk of external emission of heat or of radiation while at the same time limiting the electrical consumption.

[0144] The artificial electromagnetic radiation light source is configured to emit ultraviolet-visible (UV-visible) radiation, infrared (IR) radiation, or microwaves.

[0145] The artificial electromagnetic radiation light source comprises, for example, a plurality of light-emitting diodes (LEDs) configured to emit monochromatic ultraviolet-visible radiation with a wavelength ranging from 350 nm to 750 nm.

[0146] Preferably, the light-emitting diodes are directed radially towards the lock of hair.

[0147] Preferably, each photodetector is sensitive to UV-visible radiation.

[0148] The photodetector is sensitive to the variations in luminosity in the ultraviolet- visible radiation range.

[0149] Each photodetector 17 is a photosensitive component.

[0150] For example, the photodetector 17 is a photoresistor, also known as a lightdependent resistor (LDR).

[0151] The photoresistor is an electronic component, the resistance value of which varies on the basis of the luminosity perceived.

[0152] The higher the luminosity, the lower its resistance value (resistivity). Conversely, the lower the luminosity, the greater its resistance value (resistivity).

[0153] The photoresistor comprises, for example, a support, for example made of ceramic, and two prongs, with no polarity, for transmitting a current.

[0154] The surface of the photoresistor may be protected by an insulating resin or by a conventional lens or a lens filtering the ultraviolet radiation.

[0155] The photoresistor is an inexpensive component that is very easy to implement and has a very high sensitivity.

[0156] For example, the photodetector is a photodiode or a phototransistor.

[0157] In general, the photodetector is configured to generate a current on the basis of the luminosity.

[0158] The hair treatment device 10 further comprises an electronic control unit ECU configured to determine a control signal from the movement information in order to control the member 18 for emitting a treatment agent. The signal processing unit 19 is configured to detect the lock of hair being placed in contact with the treatment device when the variations in the current values generated by the photodetector are greater than or equal to a threshold value.

[0159] The current threshold value is, for example, between 6 nA and 20 mA per photodiode in darkness, lower values being considered to relate to ambient noise.

[0160] A signal of less than 6 nA is considered to be ambient noise.

[0161] A current “variation” is understood to be a difference between a first current value at a time t without hair nearby (starting t) and a second current value at a time t+1 or a series of current values at times t+1, t+2, . . . ; t+n.

[0162] If the current variation is zero or almost zero between the single pair of values or between each pair (t, ti) of current values or between the first and last values (t, tn), there is no movement detected between the lock of hair and the treatment device. Conversely, if the current variation is not zero, and in particular greater than or equal to the threshold value, a movement between the lock of hair and the treatment device has been detected by the signal processing unit, thus implying the presence of the lock in the device.

[0163] This is in particular the case when the treatment device is in the form of a pair of tongs comprising two articulated arms, where the arms moving together causes the passage from an environment with ambient light to an environment confined solely to the light of the treatment device.

[0164] Moreover, in the case of a pair of tongs, without a lock of hair, the current generated is constant. In other words, there is no variation in the light perceived by the photodetector.

[0165] The electronic control unit ECU is in particular configured to modify at least one treatment parameter, or even to stop the member 18 for emitting a treatment agent if no relative movement between the treatment device 10 and the lock of hair to be treated has been detected, i.e. in the case of the lock of hair being absent from the treatment device 10.

[0166] The treatment device 10 may comprise a steam-emitting member comprising a plurality of steam outlets (not shown) opening onto a treatment surface or the treatment surfaces 14, 15. As a variant, the hair treatment device 10 has a single elongate steam outlet.

[0167] The steam outlets are supplied with steam, for example, by a steam-supplying system (not shown).

[0168] The device makes it possible to treat the hair while at the same time limiting the amount of water used, thereby reinforcing the autonomy of said device.

[0169] The treatment device may further comprise a member (not shown) for emitting a cosmetic composition configured to emit a cosmetic composition onto a treatment surface or the treatment surfaces 14, 15. Figures 4 and 5 illustrate another embodiment in which the treatment device 20 is a hair brush.

[0170] As illustrated in Figures 4 and 5, the hair treatment device 20 comprises a gripping portion 21 and a treatment portion 22, referred to as “head of the brush”.

[0171] Seen from above, the treatment portion 22 may be substantially rectangular in shape with rounded comers, as may be seen in Figure 5, but it could be shaped differently. Seen from above, the treatment portion 22 could be substantially polygonal, oval or round, in particular comprising a plurality of spikes spaced regularly over the treatment surface.

[0172] The treatment portion 22 may have a substantially flat treatment surface 23. It is of course conceivable to have a curved, in particular outwardly convex, treatment surface 23, for example having a substantially cylindrical cross section with a closed or semi-cylindrical contour.

[0173] The treatment portion 22 comprises, in this case, a plurality of teeth or protrusions 22a that are arranged in a plurality of rows and extend from the treatment surface 23. The rows of teeth 22a extend along a main axis X2 of the brush 20. The teeth may be attached to the brush, in particular being made of a different material to that defining the treatment surface. The brush may have a single row of teeth, in which case it is referred to as a comb.

[0174] In an entirely non-limiting manner, one or more teeth 22a may be made of a heat-conducting material, for example of iron, aluminium, titanium, stainless steel, graphite or ceramic, optionally provided with a coating.

[0175] The hair treatment device 20 comprises a member 26 for emitting a treatment agent comprising, in this case, a plurality of heating teeth 22a.

[0176] As a variant, the member 26 for emitting a treatment agent may comprise an artificial electromagnetic radiation light source near to the photodetectors 27. However, the brush is already perceiving the ambient light, and therefore an additional light source is not indispensable.

[0177] As illustrated in Figure 5, the hair treatment device 20 comprises a motion detection unit configured to detect a relative movement between a treatment device 10 and the lock of hair to be treated.

[0178] The detection unit comprises at least one photodetector, in this case three photodetectors 27, configured to perceive a luminosity and to generate a current value.

[0179] More precisely, the photodetectors 27 are configured to generate a current, i.e. either a voltage or an intensity that depends on the resistivity, on the basis of the luminosity perceived.

[0180] The detection unit further comprises a signal processing unit 29 configured to read the current values transmitted by the photodetector and to deduce movement information therefrom on the basis of a current variation. The signal processing unit 29 is, in this case, housed in the body of the hair treatment device 20, in particular in the gripping portion 21.

[0181] Each photodetector 27 is a photosensitive component.

[0182] For example, the photodetectors 27 are photoresistors, which are identical to those described in the embodiment with reference to Figures 1 to 3.

[0183] As a variant, the photodetector 27 is a photodiode or a phototransistor.

[0184] In general, the photodetector 27 is configured to generate a current on the basis of the luminosity.

[0185] The photodetectors 27 are positioned on a side of the brush 20 in order to perceive the ambient light.

[0186] The hair treatment device 20 comprises an electronic control unit ECU, in this case housed in the body of the hair treatment device 20, in particular in the gripping portion 21, configured to determine a control signal from the movement information in order to control the member 26 for emitting a treatment agent.

[0187] The electronic control unit ECU is in particular configured to modify at least one treatment parameter, or even to stop the member 26 for emitting a treatment agent if no presence of the lock of hair to be treated has been detected.

[0188] The signal processing unit 29 is configured to detect the lock of hair being placed in contact with the treatment device 20 when the variations in the current values generated by the photodetector 27 are greater than or equal to a threshold value.

[0189] The current threshold value is, for example, between 6 nA and 20 mA per photodiode in darkness, lower values being considered to relate to ambient noise.

[0190] A signal of less than 6 nA is considered to be ambient noise.

[0191] A current “variation” is understood to be a difference between a first current value at a time t without hair nearby (starting t) and a second current value at a time t+1 or a series of current values at times t+1, t+2, . . . , t+n.

[0192] If the current variation is zero or almost zero between the single pair of values or between each pair (t, ti) of current values or between the first and last values (t, tn), there is no movement detected between the lock of hair and the treatment device. Conversely, if the current variation is not zero, and in particular greater than or equal to the threshold value, a movement between the lock of hair and the treatment device 20 has been detected by the signal processing unit 29, thus implying the presence of the lock in the device 20.

[0193] When the member 26 for emitting a treatment agent comprises a heat source, the treatment surface 23 and / or the teeth 22a may be heated by one or more heating elements (not shown) electrically powered via an electrical wire to the mains or to a base station, or by primary or secondary batteries.

[0194] The heating elements may be, for example, one or more heating resistors.

[0195] Preferably, the treatment surface 23 and the teeth 22a are heated. The hair treatment device 20 may comprise, in an entirely non-limiting manner, a plurality of steam outlets (not shown) opening onto the treatment surface 23, which steam outlets may alternate with the teeth 22a of one of the rows of teeth, in this case the central row 20. As a variant, the hair treatment device 20 has a single elongate steam outlet.

[0196] The steam outlets are supplied with steam, for example, by a steam-supplying system (not shown).

[0197] As illustrated in Figure 6, the hair treatment method 30 comprises a step 31 of verifying the activation of the hair treatment device 10.

[0198] Activation may take place for example by connecting the appliance to the mains and / or by pressing an on switch present on the hair treatment device 10, for example on the gripping portion, in particular in the case of portable appliances equipped with primary or secondary batteries.

[0199] The hair treatment method 30 further comprises a step 35 in which current values generated by the photodetectors 17, 27 and received by the signal processing unit 19, 29 are read, movement information is deduced therefrom on the basis of a variation in said current value read and a control signal is determined from the movement information in order to control the member for emitting at least one treatment agent.

[0200] In step 36, the variation in said current values is compared with a threshold value XXI, which is considered to relate to ambient noise.

[0201] If the variation in the current values is greater than or equal to the threshold value XXI, a movement between the lock of hair and the treatment device has been detected by the signal processing unit, thus implying the presence of the lock in the device 10 and, in step 37, the member 18, 26 for emitting the one or more treatment agents is triggered, either immediately or after a fixed latency.

[0202] Provision could be made for a prior step between step 35 and step 36 in which a current variation is determined.

[0203] As a variant, it would be possible to consider the almost-zero slope received by the photodetector in the case of an empty pair of tongs, i.e. with no locks, to analyse a group of current values detected by the photodetector and received by the signal processing unit, and to compare said group of values with the almost-zero slope. If this group of values has a different slope to the almost-zero slope, it is considered that there is movement information and, in step 37, the member 18, 26 for emitting the one or more treatment agents is triggered, either immediately or after a fixed latency.

[0204] A current “variation” is understood to be a difference between a first current value at a time t without hair nearby (starting t) and a second current value at a time t+1 or a series of current values at times t+1, t+2, . . . , t+n. If, before treatment or at the end of treatment, the variation in the current values relative to a time t without hair being present is less than the threshold value XXI, i.e. there is no detected presence of the lock of hair, in step 38, the duration for which said variation in the current values is less than the threshold value XXI is compared with a time threshold value XX2.

[0205] If the duration is greater than or equal to said time threshold value XX2, the electronic control unit ECU controls, in step 39, the member 18, 26 for emitting a treatment agent in order to prevent the emission or to reduce its lighting power to a safety value in the case in which the treatment agent is an electromagnetic light source, or even to stop its lighting power. In other words, the emission of the treatment is stopped.

[0206] If the duration is less than the time threshold value XX2, in step 40, the member 18, 26 for emitting a treatment agent is kept switched on. In other words, the emission of the treatment is continued.

[0207] The current threshold value XXI is, for example, between 6 nA and 20 mA per photodiode, lower values being considered to relate to ambient noise.

[0208] A signal of less than 6 nA is considered to be ambient noise.

[0209] The time threshold value XX2 is, for example, between 0.1 s and 5 s.

[0210] The treatment method 30 may further comprise, in an entirely non-limiting manner, a step of applying a cosmetic composition, such as for example a composition for cleaning, dyeing, bleaching, conditioning, restoring or shaping hair.

[0211] Figures 7A to 7C illustrate examples of signal processing on the basis of the movement, on the y-axis, along the lock of hair to be treated, of the time, on the x-axis, and of the tone depth of the lock of hair to be treated.

[0212] The tone depth of a hair is defined by TDn with n being between 1 and 10, 1 being the lightest and 10 the darkest.

[0213] Figure 7A corresponds to a tone depth TD9, i.e. a black hair.

[0214] Figure 7B corresponds to a tone depth TD4, i.e. a chestnut-brown hair.

[0215] Figure 7C corresponds to a tone depth TD1, i.e. a blond hair.

[0216] It is observed that the photodetectors receive different levels of luminosity as they are moved along the lock of hair and that the current signal generated forms an oscillation.

[0217] The perception of the luminosity by the photodetector is clearer in the case of a dark hair greater than a tone depth TD4. The invention is not limited to a hair treatment device in the form of a brush or of a pair of tongs.

[0218] Specifically, provision could be made for the treatment device 10 to comprise just one single arm 11.

[0219] Provision could also be made for the treatment device to have another shape. The hair treatment device 10, 20 may have a user interface (not shown) enabling the user to enter various input data, in particular a luminosity of the electromagnetic light source, an operating temperature, a steam flow rate or a characteristic of the hair, or to deactivate one or more functions of the hair treatment device 10, 20, in particular the application of steam or the application of heat. The interface may also enable the hair treatment device 10, 20 to transmit information to the user, in particular the temperature of the treatment surface or of the teeth in the case of a brush, or the end of heating of the vaporization chamber and / or of the treatment surface and / or of the teeth. Unlike conventional motion detectors such as accelerometers, the detection unit according to the invention makes it possible to detect almost constant movements, and even movements of the hair when the device is static. By virtue of the treatment device according to the invention, hair can be treated in a controlled manner by limiting the unwanted risk of external emission of heat or of radiation while at the same time limiting the electrical consumption.

Claims

CLAIMS1. Hair treatment device (10, 20) for treating at least one lock of hair to be treated, comprising a member (18, 26) for emitting at least one treatment agent from the group comprising an artificial electromagnetic radiation light source or a heat source, characterized in that the hair treatment device (10, 20) comprises:- a motion detection unit configured to detect a relative movement between the treatment device (10, 20) and the lock of hair to be treated and comprising at least one photodetector (17, 27) configured to perceive a luminosity and to generate at least one current value on the basis of the luminosity perceived; and- a signal processing unit (19, 29) configured to read current values transmitted by the photodetector (17, 27) and to deduce movement information therefrom on the basis of a variation in said current value read; and- an electronic control unit (ECU) configured to determine a control signal from the movement information in order to control the member (18, 26) for emitting the one or more treatment agents.

2. Hair treatment device (10, 20) according to Claim 1, wherein the signal processing unit (19, 29) is configured to detect the lock of hair being placed in contact with the treatment device (10, 20) when the variation in the current values transmitted by the photodetector (17, 27) is greater than or equal to a threshold value.

3. Hair treatment device (10, 20) according to Claim 1 or 2, wherein the artificial electromagnetic radiation light source is configured to emit ultraviolet-visible radiation, infrared radiation, or microwaves.

4. Hair treatment device (10, 20) according to Claim 3, wherein the artificial electromagnetic radiation light source comprises a plurality of light-emitting diodes (LEDs) configured to emit monochromatic ultraviolet-visible radiation with a wavelength of between 350 nm and 750 nm.

5. Hair treatment device (10, 20) according to any one of the preceding claims, wherein the photodetector (17, 27) is a photosensitive component, preferably a photoresistor or a photodiode or a phototransistor.

6. Hair treatment device (20) according to any one of the preceding claims, wherein said device (20) is a hair brush comprising a gripping portion (21) and a treatment portion (22) comprising a treatment surface (23) and a plurality of teeth (22a) that are arranged in a plurality of rows and extend from the treatment surface (23), and wherein the member (26) for emitting a treatment agent is positioned on the treatment surface (23).

7. Hair treatment device (20) according to Claim 6, wherein the photodetector (27) is positioned on a side of said device (20) in order to perceive the ambient light.

8. Hair treatment device (20) according to Claim 6 or 7, wherein, when the member (26) for emitting at least one treatment agent comprises a heat source, the treatment surface (23) and / or the teeth (22a) may be heated by one or more heating elements.

9. Hair treatment device (10) according to any one of Claims 1 to 5, further comprising an additional light source situated facing the photodetector (17).

10. Hair treatment device (10) according to any one of Claims 1 to 5 or 9, wherein the treatment device (10) has the overall shape of a pair of tongs comprising two arms (11, 12) that can move relative to one another between a separated position and a closed position in which the lock of hair to be treated is in contact with the inner surfaces (I la, 12a) of said arms (11, 12).

11. Hair treatment device (10) according to Claim 10, wherein the two arms (11, 12) each comprise a gripping portion (11b, 12b) on which the user can press in order to move the two arms together into the closed position and a treatment portion (11c, 12c) situated at the end of the corresponding arm and each comprising a treatment surface (14, 15), said treatment surfaces (14, 15) facing one another.

12. Hair treatment device (10) according to Claim 11, wherein the member for emitting at least one treatment agent comprises an electromagnetic radiation source and wherein said electromagnetic radiation light source (18) is integrated onto the treatment surface (15) of one of the arms (12).

13. Hair treatment device (10) according to Claim 11 or 12, wherein the photodetector (17) is integrated onto the same treatment surface (15) as the electromagnetic radiation light source (18), and preferably the photodetector (17) is integrated onto a lateral edge of the treatment surface (15) and / or the photodetector (17) is integrated onto the treatment surface (15) upstream of the light source (18) in the direction of insertion and of passage of the lock of hair.

14. Hair treatment device (10) according to Claim 12, comprising an additional light source (18), integrated onto the treatment surface (14) of the other arm (11), facing the photodetector (17).

15. Hair treatment device (10) according to Claim 12, wherein the photodetector (17) and the electromagnetic radiation light source (18) are integrated onto two opposing treatment surfaces (14, 15).

16. Hair treatment device (10, 20) according to Claim 6 or 11, in combination with any one of the preceding claims, comprising a steam-emitting member comprising a plurality of steam outlets opening onto at least one treatment surface (14, 15, 23).

17. Hair treatment device (10, 20) according to Claim 6 or 11, in combination with any one of the preceding claims, comprising a member for emitting a cosmetic composition onto at least one treatment surface (14, 15, 23).

18. Hair treatment method (30) for treating at least one lock of hair to be treated, comprising:- a step (31) of verifying the activation of a hair treatment device (10, 20) for treating at least one lock of hair to be treated, comprising a member (18, 26) for emitting at least one treatment agent from the group comprising an artificial electromagnetic radiation light source or a heat source, a motion detection unit configured to detect a relative movement between the treatment device (10, 20) and the lock of hair to be treated; and comprising at least one photodetector (17, 27) configured to perceive a luminosity and to generate at least one current value on the basis of the luminosity perceived and a signal processing unit (19, 29) configured to read current values transmitted by the photodetector (17, 27) and to deduce movement information therefrom on the basis of a variation in said current value read; and an electronic control unit (ECU) configured to determine a control signal from the movement information in order to control the member (18, 26) for emitting the one or more treatment agents, the method (30) comprising:- a step (33) of switching on the member (18, 26) for emitting the one or more treatment agents;- a step (35) of reading the current values generated by the photodetector (17, 27) and received by said signal processing unit (19, 29), of deducing movement information on the basis of a variation in said current value read and a control signal is determined from the movement information in order to control the member (18, 26) for emitting the one or more treatment agents;- a step (36) of comparing the variation in said current values with a threshold value (XXI),- if the variation in the current values is greater than or equal to the threshold value (XXI), the member (18, 26) for emitting the one or more treatment agents is triggered,- if, before treatment or at the end of treatment, the variation in the current values relative to a time (t) without hair being present is less than the threshold value (XXI), in a step (38), the duration for which said variation in the current values is less than the threshold value (XXI) is compared with a time threshold value (XX2), and- if said duration is greater than or equal to the time threshold value (XX2), in a step (39), the member (18, 26) for emitting the one or more treatment agents is controlled in order to stop or reduce its power to a safety value.

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