HAIR TREATMENT DEVICE

Abstract

A device for treating at least one lock of hair, comprising: at least one device (20) for applying mechanical stress to the hair, having a reception surface intended to receive the lock of hair, this surface being greater in width L in a direction perpendicular to said lock, a microwave-proof chamber which is configured so as to receive the mechanical-stress-application device (20) and at least one part of the hair to be treated, a microwave emission antenna (30) placed inside the chamber, this antenna extending axially over a distance D at least equal to L/2.

Claims

1. A device for treating at least one lock of hair, comprising: at least one device for applying mechanical stress to the hair, having a reception surface intended to receive the lock of hair, this surface being greater in width L in a direction perpendicular to said lock, a microwave-proof chamber which is configured so as to receive the mechanical-stress-application device and at least one part of the hair to be treated, a helical microwave emission antenna placed inside the mechanical-stress-application device, the power of the microwave ranging between 100 and 250 W, this antenna extending axially over a distance D at least equal to L/2.

2. The device as claimed in claim 1, this antenna extending axially over a distance D at least equal to 80% of the width L of the reception surface intended to receive the lock of hair, in a direction perpendicular to said lock.

3. The device as claimed in claim 1, the frequency of the microwave used is strictly greater than 2 GHz and less than 3 GHz.

4. The device as claimed in claim 3, wherein the antenna has a fixed helical pitch, of between 4 and 5 mm.

5. The device as claimed in claim 4, wherein the axial extension of the antenna is between 15 and 80 mm.

6. The device as claimed in claim 1, wherein the chamber has a housing configured so as to receive the mechanical-stress-application device and at least one part of the hair to be treated, the microwave emission antenna being placed inside the chamber, the housing for receiving the mechanical-constraint-application device being defined at least partially by a drawer that is mobile relative to the antenna between an open position allowing the emplacement and removal of the mechanical-constraint-application device, and a closed position in which the chamber is microwave-proof and the antenna approaches the mechanical-constraint-application device.

7. The device as claimed in claim 6, wherein the antenna and the mechanical-constraint-application device are arranged in such a way that, in the closed position of the drawer, the antenna is engaged inside the mechanical-constraint-application device.

8. The device as claimed in claim 6, the mechanical-stress-application device being a curler, the device comprising a casing carrying the antenna, the drawer sliding along the longitudinal axis of the casing, the axis of the antenna being parallel to an axis of sliding of the drawer, the casing comprising an arc-shaped lug, engaged in a corresponding slide of the drawer, the internal surface of the housing being covered with a conductive coating, an exit slit for the hair being formed between the casing and the drawer, the coating being configured to come at rest, in the absence of hair, to block the slit, the device comprising an end plate closing the housing at its end opposite the casing.

9. The device as claimed in claim 1, wherein the chamber is defined at least partially by a casing which has a housing configured so as to receive the mechanical-stress-application device and at least one part of the hair to be treated, and by a cover that pivots relative to the casing between an open position giving access to the housing and a closed position, the microwave emission antenna being placed inside the housing, the housing being open at one end so as to allow, when the cover is open, the emplacement and removal of the mechanical-constraint-application device by an axial movement relative to the casing, the mechanical-constrained-application device and the antenna being arranged in such a way that the antenna inserts into the mechanical-constraint-application device when the latter is put in place in the housing.

10. The device as claimed in claim 1, comprising a slit for the hair to exit the chamber, this slit being edged by an electrically conductive coating, which fits over the hair in order to produce the microwave-proofness when the chamber is closed.

11. The device as claimed in claim 1, wherein the length of the antenna represents at least 50%, of the length of the mechanical-stress-application device.

12. A cosmetic process for treating the hair, in particular using a treatment device as defined in claim 1, comprising at least the steps consisting in: a) applying a mechanical stress to at least one lock of hair, via a mechanical-stress-application device, having a reception surface intended to receive the lock of hair, this surface being greater in width L in a direction perpendicular to said lock, b) exposing the hair thus placed under mechanical stress to microwaves by virtue of a microwave emission antenna placed inside the mechanical-stress-application device, this antenna extending axially over a distance D which is at least equal to L/2, the mechanical-stress-application device and at least one part of the lock to be treated being received in a microwave-proof chamber.

13. The process as claimed in claim 12, wherein the application of the mechanical stress is carried out with a curler, the antenna being helical and placed inside the curler.

14. The device as claimed in claim 4, the radius of the helix being constant and between 4 and 10 mm.

15. The device as claimed in claim 5, wherein the axial extension of the antenna is between 65 and 75 mm.

16. The device as claimed in claim 11, wherein the length of the antenna represents at least 70% of the length of the mechanical-stress-application device.

Description

DESCRIPTION OF THE FIGURES

[0211] The invention may be better understood from reading the following detailed description of non-limiting implementation examples thereof, and with reference to the appended drawing, in which:

[0212] FIG. 1 is a partial schematic representation of an example of a treatment device according to the invention,

[0213] FIG. 2 is the open hand-held piece and the mechanical-stress-application device once extracted,

[0214] FIG. 3 is the closed hand-held piece,

[0215] FIG. 4 is a side view of the hand-held piece from FIG. 3,

[0216] FIG. 5 is a longitudinal section along V-V of FIG. 4,

[0217] FIG. 6 is a cross section along VI-VI of FIG. 5,

[0218] FIG. 7 is a longitudinal cross section along VII-VII of FIG. 5,

[0219] FIG. 8 is a view, similar to FIG. 6, when the chamber is closed,

[0220] FIG. 9 is a view, similar to FIG. 2, of an embodiment variant of the hand-held piece,

[0221] FIG. 10 is the hand-held piece of FIG. 9, in the closed position,

[0222] FIG. 11 is a side view of the hand-held piece in the open position with the constraint application device in place in the corresponding housing of the hand-held piece,

[0223] FIG. 12 is a cross section of the hand-held piece,

[0224] FIG. 13 is a longitudinal section along XIII-XIII of FIG. 12,

[0225] FIG. 14 is a view, similar to FIG. 1, of a variant of the treatment device according to the invention, and

[0226] FIGS. 15 and 16 represent our results of comparative tests.

[0227] FIG. 1 shows a treatment device 100 according to the invention, comprising a hand-held piece 3 connected via a flexible waveguide 2 to a base station 1 comprising a microwave generator.

[0228] The flexible waveguide 2 is constituted by a shielded cable.

[0229] The hand-held piece 3 is anticipated to be manipulated by the user in order to be placed in proximity to the person's head for treating at least one lock of hair H, as illustrated.

[0230] The hand-held piece 3 can be produced in various ways and defines a microwave-proof treatment chamber 4.

[0231] FIGS. 2 to 8 show a first embodiment example of the hand-held piece 3.

[0232] The flexible waveguide 2 has been represented only very partially on these figures.

[0233] The hand-held piece 3 comprises a casing 10 on which a cover 11 is articulated by means of an axis 12.

[0234] The casing 10 defines a housing for receiving a mechanical-constraint-application device, constituted, in the example in question, by a curler 20.

[0235] Said curler comprises several branches 21 which define a surface for receiving the hair H, of width L, measured along the longitudinal axis X of the curler 20.

[0236] The axis X is, in this example, parallel to the axis of rotation of the cover 11.

[0237] In the example in question, the curler 20 comprises four branches 21, which are slightly curved toward the axis X and pass by a minimum distance to the axis X at about mid-length.

[0238] The branches 21 can have ribs 23 oriented perpendicular to the axis X for assisting in holding the lock spread out on the branches 21, while preferably occupying the entire width L as uniformly as possible.

[0239] The branches 21 connect at their ends to annular parts 25.

[0240] The curler 20 has teeth 26 at the ends of the branches 21, which laterally delimit the surface for receiving the hair.

[0241] The curler 20 can be made of any dielectric material, preferably of PTFE.

[0242] The curler 20 preferably has a symmetrical form of revolution relative to a median plane of symmetry perpendicular to the axis X.

[0243] The casing 10 carries an antenna 30 which is, in the example shown, helical in shape, with a longitudinal axis 7 which merges with the axis X when the curler 20 is in place.

[0244] The antenna 30 is, in the example in question, made up of a helical metal wire, place in a tube 32 of a dielectric material, for example silicone or PTFE.

[0245] The presence of this tube 32 facilitates the insertion of the antenna into the curler 20.

[0246] The casing 10 defines a housing 6 in which the curler 20 is placed.

[0247] The antenna 30 is supported at an axial end of the casing 10 by a plate 14 of the casing 10, which has a semicircular outline.

[0248] The cover 11 has a similar plate 15 on the opposite side, closing the opening 5 of the housing 6, by which the curler 20 is introduced into the hand-held piece 3.

[0249] The interior surface of the housing 6 is defined by an electrically conductive coating 7 which makes it possible to reflect the microwaves and makes the chamber 4 microwave-proof.

[0250] The curler 20 comprises blocks 27 with a widened head, which connect at their base to the corresponding annular parts 25, which press against the coating 7, as shown in FIG. 8, so as to maintain the curler centered in the housing 6.

[0251] The blocks 27 are for example located between the teeth 26, as shown.

[0252] The coating 7 can be formed from a conductive foam which is for example semi-cylindrical in shape along the curler on the cover and the casing, in the form of a disk for the plate 15 and of a ring for the plate 14.

[0253] The casing 10 and the cover 11 define an exit slit 19 for the hair, located at the bottom of a reinforcement 18, on the side opposite the axis 12 of the hinge.

[0254] The coating 7 preferably protrudes into the slit 19 for the hair, as can be seen in FIG. 8, so as to produce a good closure seal despite the hair passing through.

[0255] The edge of the coating can thus go slightly beyond, at 17, the edge of the body of the cover and that of the casing, as shown in FIG. 6, for closing the slit 19.

[0256] The hand-held piece 3 comprises a member for locking the cover in the closed position, not represented, and also an opening detector.

[0257] The width W of the slit 19 can be slightly greater than L, the length of the housing 6 being substantially equal to the length of the curler 20, such that the latter is immobilized both axially and radially in the housing 6, to within a slight amount of play.

[0258] In order to use the hand-held piece 3, a lock of wet hair is wound on the curler 20, then the latter is placed inside the casing 10 by moving it laterally relative to said casing, while introducing it by the opening 5. The cover 11 is then closed again, and the hair exits via the slit 19. Once the microwave exposure has been performed, the lock of hair is extracted by performing the operations in the reverse order.

[0259] A variant of the hand-held piece 3 will now be described with reference to FIGS. 9 to 13.

[0260] Said hand-held piece comprises a casing 40 and a drawer 50 that can slide along the longitudinal axis of the casing.

[0261] The casing 14 can in particular comprise an arc-shaped lug 41, engaged in a corresponding slide 51 of the drawer 50, as shown in FIG. 12. The lug 41 can be provided with a thickening 42 at the end, retained in a corresponding well, so as to hold the lug 41 in the slide 51.

[0262] The casing 40 carries the antenna 30.

[0263] The axis of the antenna 30 is parallel to the axis of sliding of the drawer 50.

[0264] The internal surface of the housing 6 for receiving the curler is covered with a conductive coating 7 as in the example described above.

[0265] An exit slit 19 for the hair is formed between the casing 40 and the drawer 50, the coating coming at rest, in the absence of hair, to block this slit as illustrated in FIG. 12.

[0266] An end plate 54 closes the housing 6 at its end opposite the casing 40.

[0267] In order to use the hand-held piece 3, the curler with the lock wound on it is introduced into the housing 6, while the drawer is in the open position, as shown in FIG. 9. In this position, the drawer is sufficiently advanced for the antenna not to impair the emplacement of the curler.

[0268] The free end of the antenna 30 is at a distance m from the curler 20 in place in the housing 6, for example between 2 and 10 mm.

[0269] The casing 40 is then slid along so as to close the housing 6. At this time, the hair exits via the slit 19.

[0270] To extract the treated hair, the operations are performed in reverse order.

[0271] The external diameter of the antenna 30 is for example 9.2 mm for an internal diameter of the body of the curler of 22 mm.

[0272] A temperature detector may be present in the chamber 4, for example on an internal surface thereof, in order to measure the temperature of the treated lock of hair, and a control system, for example a microprocessor system, may make it possible to interrupt or modify the microwave emission in the event of a detected temperature above a predefined threshold.

[0273] Several hand-held pieces 3 may be connected to one and the same generator 1, as shown in FIG. 14.

Comparative Tests: Curler with Rectilinear Antenna and Curler with Helical Antenna

[0274] A curler with a straight antenna which comprises a central straight part formed from a hollow dielectric tube, made of glass, with two ends formed by PTFE disks, located on either side of the central part, is used.

[0275] The curler with a helical antenna comprises a metal antenna in the shape of the helix wound on a cylindrical PTFE bar, protected by a thin PTFE glove finger in order to facilitate the handling thereof and the introduction thereof into the curler.

TABLE-US-00001 Average Average Number time up to Temperature percentage of Curler/antenna of tests 10 C. homogeneity reflected power Straight antenna 3 5 minutes +/ 2 50% +/ 1.2 Helical antenna 4 40 s at 100 W Homogeneous 32% +/ 0.5 2.5 min at improved (standard 50 W error less than 20)

[0276] The increase in temperature over time for hair wound on curlers with a straight antenna and on those with a helical antenna is shown in FIGS. 15 and 16 respectively.

[0277] In the case of the straight antenna, the equivalent electric circuit has capacities C between the core and the walls and there is capacitive coupling.

[0278] The incident field is perpendicular to the surface of the core at any point and is therefore also perpendicular to the walls of the curler.

[0279] In the case of the helical antenna, there is a coupling which adds to that between the core and the walls, namely a coupling between the loops of the antenna. This induces capacitive and inductive couplings.

[0280] The field E is perpendicular to the surface of the antenna at any point and is not therefore perpendicular at all points to the walls of the curler. There is therefore a coming together of the field maxima and of the heat sources which are distributed better throughout the entire volume of the lock, which contributes to making the temperature uniform.

[0281] Increasing the length of the antenna increases the number of maxima and minima of the electric field around the antenna and, consequently, increases the number of heat sources in the lock of hair.

[0282] Furthermore, in the case of the helical antenna, the following are observed: [0283] a decrease in the reflected power (Pr), [0284] an improvement in the homogeneity of the temperature along the curler between the straight antenna and the helical antenna for one and the same curler.

[0285] The advantage of an antenna having a relatively long length, which is in particular helical, which makes it possible to generate multiple heat sources along the lock, can thus be seen from these tests. These sources are quite close so as to contribute to making the desired heating uniform. The method of propagation of the microwaves in the lock is not affected by the change in the dielectric characteristics.