U.S. patent application number 12/747360 was filed with the patent office on 2011-01-27 for hair treatment method involving irradiation through an optical medium.
This patent application is currently assigned to L'Oreal. Invention is credited to Henri Samain.
Application Number | 20110017227 12/747360 |
Document ID | / |
Family ID | 39652500 |
Filed Date | 2011-01-27 |
United States Patent
Application |
20110017227 |
Kind Code |
A1 |
Samain; Henri |
January 27, 2011 |
HAIR TREATMENT METHOD INVOLVING IRRADIATION THROUGH AN OPTICAL
MEDIUM
Abstract
Hair treatment method in which at least one portion of at least
one hair (H) is exposed to at least one pulse of light through a
fluid or solidified transparent medium (M) with a refractive index
of 1.3 or higher, this medium being in contact with the hair or
hairs and extending between the hair or hairs and a surface (I) at
which light enters the medium, preferably of predefined form.
Inventors: |
Samain; Henri; (Bievres,
FR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, L.L.P.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
L'Oreal
Paris
FR
|
Family ID: |
39652500 |
Appl. No.: |
12/747360 |
Filed: |
December 10, 2008 |
PCT Filed: |
December 10, 2008 |
PCT NO: |
PCT/FR08/52266 |
371 Date: |
October 7, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61006540 |
Jan 18, 2008 |
|
|
|
Current U.S.
Class: |
132/200 ;
132/212 |
Current CPC
Class: |
A61N 5/0617 20130101;
A61N 2005/0662 20130101; A61B 2018/206 20130101; A61N 2005/067
20130101; A45D 2200/205 20130101; A45D 2044/007 20130101; A45D
19/0066 20210101; A61B 2018/00476 20130101; A61B 18/203 20130101;
A45D 2007/001 20130101; A45D 19/012 20210101; A45D 2200/1036
20130101; A61N 2005/063 20130101; A61N 2005/0666 20130101 |
Class at
Publication: |
132/200 ;
132/212 |
International
Class: |
A45D 7/00 20060101
A45D007/00; A45D 44/00 20060101 A45D044/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 10, 2007 |
FR |
0759677 |
Claims
1. A method for treatment of hair of the scalp, comprising:
exposing at least a portion of at least one hair of the scalp to at
least one light pulse through a transparent medium that is fluid or
that has solidified, wherein a refractive index of the transparent
medium is greater than or equal to 1.3, the transparent medium is
in contact with the scalp hair and extending between the scalp hair
and a surface for the entry of light into the medium.
2. The method according to claim 1, wherein a shape of the light
entry surface is defined by a transparent wall of an irradiation
device in contact with the transparent medium.
3. The method according to claim 1, wherein a shape of the light
entry surface is defined by levelling or flattening the medium
prior to the exposure to the light pulse.
4. The method according to claim 1, wherein an entire section of at
least one treated hair is included in the transparent medium.
5. The method according to claim 1, wherein at least two layers of
superposed hairs are included in the transparent medium and are
simultaneously exposed to the light pulse(s).
6. The method according to claim 1, wherein the treated scalp hair
is confined in a guide system defining a treatment space comprising
the scalp hairs and the transparent medium.
7. The method according to claim 7, wherein the scalp hairs are
packed into the treatment space.
8. The method according to claim 1, wherein a peak power of the
light pulse is greater than or equal to 10.sup.5 W.
9. The method according to claim 1, wherein the transparent medium
comprises at least one organic compound in a mass content of
greater than or equal to 25%.
10. The method according to claim 1, wherein the transparent medium
is dispensed on the scalp hairs from at least one orifice for
delivering said transparent medium, occupying a variable position
relative to the scalp hairs, between two light pulses.
11. The method according to claim 1, wherein a refractive index of
the medium is greater than or equal to 1.4.
12. The method according to claim 1, wherein the scalp hairs are
bleached, modified in shape or bleached and modified in shape.
13. The method according to claim 1, wherein the duration of the
pulses is greater than 5.times.10.sup.-12 s.
14. A scalp hair treatment system, comprising: a source of pulsed
light, a source of a fluid or solidifiable transparent medium,
having a refractive index of greater than or equal to 1.3, a system
for guiding the scalp hairs to be treated, configured to receive
the scalp hairs to be treated, wherein the treatment system is
configured to bring the transparent medium into contact with the
scalp hairs to be treated.
15. The system according to claim 14, wherein the treatment space
exposed to the light pulses surrounds the treated scalp hair(s) on
all sides, in at least one section taken transversely relative to
the treated scalp hair(s).
16. The method according to claim 1, wherein the surface for the
entry of the light into the medium is of a predefined shape.
17. The system according to claim 14, wherein the system is
configured to define a surface of predetermined shape for entry of
light into the medium.
Description
[0001] The present invention relates to the cosmetic treatment of
human or animal keratin fibers. The invention more particularly
relates to hair treatments by irradiation.
[0002] Many hair treatments use light for treating the hair, for
example for more or less substantially bleaching the melanin.
[0003] Applications U.S. Pat. No. 4,792,341, U.S. Pat. No.
5,246,019, U.S. Pat. No. 5,303,722, EP 685 220 A1, EP 682 937 B1
and US 2007 10167936 A1 thus describe hair bleaching methods using
irradiation devices.
[0004] U.S. Pat. No. 5,246,019 discloses the application of a
bleaching composition (alcoholic or hydro-alcoholic solution,
emulsion or gel) present on the hair at the time of irradiation,
which irradiation preferably uses continuous light. Rinsing is then
performed.
[0005] EP 685 220 teaches of subjecting wet hair to a bleaching
treatment with pulsed light.
[0006] EP 682 937 teaches of cooling the treated area by
circulating a fluid, for example a gas comprising water
droplets.
[0007] The light must be used so as not to degrade the keratin
fibers, and complying with irradiation conditions that avoid
degradation of the fiber proves to be a constraint on the
development of these methods.
[0008] It has been proposed to use cooling devices to avoid heating
the keratin fibers. However, cooling does not prevent the fibers
from being degraded under certain irradiation conditions and makes
the treatment system more complex and expensive. Furthermore,
cooling devices are generally not suited to firing frequencies of
greater than 100 Hz.
[0009] There is a need to benefit from a method for treating hair
by irradiation, which is rapid while at the same time limiting the
risks of degradation of the hair, and the invention is directed
toward satisfying this need.
[0010] A subject of the invention is thus, according to one of its
aspects, a hair treatment method in which at least a portion of at
least one hair is exposed to at least one light pulse through a
transparent medium, which is fluid or which has solidified, with a
refractive index advantageously of greater than or equal to 1.3 (at
20.degree. C.) and if possible greater than 1.4, this medium being
in contact with the hair and extending between the hair and a
surface of the medium, via which the light enters the medium.
[0011] The presence of the transparent medium makes it possible to
use light pulses with a peak power of greater than or equal to
10.sup.5 W, for example, reducing or even eliminating the risk of
degradation of the hairs at high power values. The firing frequency
may be greater than or equal to 100 Hz, or even 1 kHz or 10
kHz.
[0012] The transparent medium also makes it possible to increase
the quality of the result obtained. As a nonlimiting example,
during bleaching, the presence of the transparent medium makes it
possible to bleach the two opposite faces of a layer of hairs.
Advantageously, since the quality is improved, it is possible to
reduce the number of firings or the energy per firing. The risk of
degrading the hairs is thus reduced. It is also possible to treat
thicker locks, since the transparent medium allows the effect of
the light radiations to be propagated to the lower layers of the
hairs of the lock.
[0013] The transparent medium also makes it possible to reduce the
odors given off.
[0014] The shape of the surface for the entry of light into the
medium is advantageously of predefined shape.
[0015] The shape of this surface may be defined by a transparent
wall of an irradiation device in contact with the transparent
medium. This transparent wall may be part of an optical channel of
the irradiation device. The transparent wall may define an optical
output of this irradiation device. As a variant, the transparent
wall is intermediate between an optical channel for the entry of
light and the transparent medium, and protects, for example, the
optical channel from the risk of soiling or wetting by the
transparent medium. The transparent wall may be mobile relative to
the hairs and/or mobile relative to a hair guide system.
[0016] The light entry surface may be defined by levelling or
flattening the medium, prior to exposure to the light pulse. The
light entry surface may or may not be in contact with the air.
[0017] The levelling or flattening of the medium may be linked to
the movement of a treatment system member.
[0018] The levelling or flattening may take place manually or be
performed automatically by the treatment system used.
[0019] The predefined shape may also be obtained with local fusion
of the transparent medium. A meltable wax may be used. Such a wax
may be introduced in powder form so as to surround the hairs.
Applying heat makes the wax melt.
[0020] The transparent medium may be liquid at the time of
irradiation. It may also be liquid when it comes into contact with
the hairs and solidify thereafter, so that it is solid at the time
of irradiation. The light entry surface may have its shape defined
while the medium is still liquid. As a variant, the predefined
shape of the entry surface may be obtained after the medium has
become solid. The term "solid" includes a state in which the medium
is gelled.
[0021] The removal of the transparent medium after irradiation may
take place by suction, drying, heating, washing and/or evaporation,
according to the nature of the medium.
[0022] The entire section of at least one treated hair may be
included in the transparent medium at the time of irradiation. At
least two and better still three layers of superposed hairs may be
included in the transparent medium and exposed simultaneously to
the light pulse(s). All the treated hairs may be at the back of the
light entry surface. As mentioned hereinabove, the transparent
medium contributes toward delivering the light to the hairs of the
layers below the first layer, which makes it possible to treat
several layers of hairs simultaneously.
[0023] The transparent medium may be cooled, where appropriate, for
example so as to maintain a temperature of between -50 and
50.degree. C.
[0024] The transparent medium may be static relative to the hairs
during the irradiation, or may circulate. Circulation of the
transparent medium is directed, for example, toward improving the
conduction of heat and avoiding the creation of hot spots.
[0025] The treated hair(s) may be confined within a guide system
defining the treatment space containing the hairs and the
transparent medium. The treatment space may be of constant or
adjustable dimensions, for example so as to adapt it to the size of
a lock to be treated.
[0026] The hairs may, where appropriate, be packed into the
treatment space.
[0027] During the treatment, the hairs may be immobile in the
treatment space. As a variant, the treatment space is moved along
the hairs during the irradiation. The movement of the treatment
space is caused, for example, by moving a transparent wall relative
to a hair guide system, this wall coming into contact with the
transparent medium and imposing its shape on the light entry
surface in the transparent medium. The transparent wall may be part
of an optical channel, for example one or more optical fibers, or
may be interposed between the optical channel and the transparent
medium. Means may be provided, where appropriate, for containing
the transparent medium in the treatment space despite the movement
of the hairs. The treatment space is, for example, delimited by
medium-confining components comprising, for example, elastically
deformable joints that are applied against the hairs. The treatment
space may also be continuously fed with transparent medium, so as
to ensure that a sufficient amount of transparent medium coats the
hairs that are to be irradiated, taking into account the losses
associated with the non-leaktightness of the treatment space.
[0028] The treatment of the hairs may be performed over a basin for
recovering the transparent medium. Depending on the nature of the
transparent medium, the recovered medium may be evacuated to the
wastewater, for example if it is pure water or water containing an
additive that is not to be recycled, or that is to be at least
partially recycled, after an optional filtration.
[0029] A composition whose role is twofold, for example making it
possible to benefit from a high refractive index and to exert
another action on the hairs, may be used to prepare the transparent
medium. For example, glycerol may be used, which will give the hair
an emollient effect.
[0030] The transparent medium may be dispensed over the hair from
at least one orifice for delivering said transparent medium, this
orifice being able to be moved relative to the hairs between two
light pulses. Delivery of the fluid intended to form the
transparent medium may take place via a delivery orifice that
occupies a variable position relative to a hair guide system.
[0031] The light treatment may be directed toward bleaching the
hairs and/or giving them remanent reshaping, which is different
than a hair-removal treatment. During the implementation of the
process, it is possible for the light not to reach the scalp or the
skin.
[0032] A subject of the invention is also, according to another of
its aspects, a treatment system comprising: [0033] an irradiation
device comprising a source of pulsed light, [0034] a source of a
fluid or solidifiable transparent medium, with a refractive index
of greater than or equal to 1.3, [0035] a system for guiding the
hairs to be treated, configured so as to receive the hairs to be
treated, the treatment system being configured to bring the
transparent medium into contact with the hairs and preferably
arranged to give a predefined shape to a surface for the entry of
light into the medium.
[0036] The treatment system may comprise a source of fluid used for
forming the transparent medium, for example a reservoir containing
said fluid, or a pipe connecting to a source of said fluid or of a
component of the medium, for example a pipe for connecting to a
water source and one or more optional reservoirs of one or more
additives to be mixed with water to form the transparent
medium.
[0037] The treatment system may bring the transparent medium into
contact with the hairs to be treated. The medium may also be placed
on the hairs outside the hair guide system.
[0038] The guide system and the light entry surface may define a
treatment surface that surrounds the treated hair(s) on all sides,
in at least one section taken transversely relative to the treated
hair(s).
[0039] The treatment system may comprise a basin for recovering the
transparent medium and also optionally a system for recirculating
to the treatment space.
[0040] The treatment system may comprise a system for cooling the
transparent medium, for example an exchanger in which circulates
the medium or a cold source in contact with the medium.
[0041] The guide system may be arranged to calibrate the amount of
hair contained in the treatment space. The cross section of this
space has, for example, a thickness corresponding to a relatively
small number of layers of hair, for example less than four
layers.
[0042] The cross section of the treatment space has, for example, a
depth of between 1 mm and 10 mm and a width of between 1 mm and 10
mm.
[0043] In one embodiment, the treatment system comprises a
transparent wall that is mobile relative to the guide system. This
guide system may define a hair-receiving canal, for example of
rectangular cross section. The transparent wall may move with an
optical output.
[0044] One or more orifices for delivering the fluid intended to
constitute the medium may emerge into said canal, this or these
orifices being located, for example, in the guide system. As a
variant, the transparent wall moves with at least one
fluid-delivering orifice, for example defined by a fluid spray
nozzle. This or these orifices may be located upstream of the
transparent wall, with regard to its movement, to ensure good
impregnation of the hairs.
[0045] The system may comprise a delivery orifice emerging into a
treatment space through which the hairs pass, this orifice being in
communication with a reservoir and being rigidly attached to an
optical output of the irradiation device.
[0046] The invention may be understood more clearly on reading the
detailed description that follows, of nonlimiting embodiments
thereof, and on examining the attached drawing, in which:
[0047] FIGS. 1a and 1b illustrate a first embodiment of the
invention,
[0048] FIGS. 2a and 2b illustrate a second embodiment of the
invention,
[0049] FIG. 3 represents, schematically and partially, an example
of a treatment system, and
[0050] FIG. 4 is a schematic and partial cross section, along IV of
FIG. 3; and
[0051] FIG. 5 represents another example of a treatment system.
TRANSPARENT MEDIUM
[0052] The medium used according to the invention is preferably
colorless, but it may be colored provided that it does not
significantly absorb the working wavelength(s) of the irradiation
light. For example, the medium may have an absorption less than or
equal to a factor of 10 of the dominant wavelength of the
irradiation light.
[0053] The transparent medium has a refractive index of greater
than or equal to 1.3, preferably greater than or equal to 1.4, or
even 1.41, 1.42, 1.43, 1.44 or 1.45, at 20.degree. C.
[0054] The transparent medium may contain at least one organic
compound in a mass content of greater than or equal to 1%.
[0055] The medium comprises, for example, at least one organic
solvent chosen from alcohols, polyols, ketones and silicones, and
mixtures thereof.
[0056] The medium contains, for example, ethanol with a refractive
index of 1.36, glycerol with a refractive index of 1.47 or acetone
with a refractive index of 1.36, for example in an amount by mass
of greater than or equal to 25% relative to the total weight of the
medium.
[0057] The medium may also be a fluid that solidifies.
[0058] Compositions that are capable of setting to a solid when the
solvent evaporates off may be used, for example, a concentrated
latex composition of a material that can coalesce by virtue of its
Tg (glass transition temperature) and/or the presence of
plasticizers. Moreover, use may be made of materials which, by
chemical reaction or by physicochemical bonding, can set to a
solid, for example a reactive silicone. The advantage of this
approach is that it enables the light irradiation to be performed
without the movements inherent in the manipulations causing the
hairs to move relative to each other. Any risks of certain parts of
the hair being overexposed and other parts underexposed, in
particular when it is desired to perform several passages, are thus
limited.
[0059] Preferably, the medium used is polar and has a capacity for
wetting the surface of the hairs, for instance water or
alcohol.
[0060] A fast-evaporating fluid may also be used, for instance a
light alkane such as butane or pentane, an ether, for instance
dimethyl ether or diethyl ether, a volatile silicone, acetone or an
alkyl acetate.
[0061] The temperature of the transparent medium, at the time of
irradiation, may be between -80.degree. C. and 80.degree. C.
[0062] The medium may be chemically inert with respect to the
hairs. The medium may especially not produce any photochemical
activation of the hairs. The medium may be free of oxidizing agent,
especially H.sub.2O.sub.2.
[0063] If the illumination is in the UV spectrum, it is possible to
use a material that filters out UV little or not at all.
Irradiation Device
[0064] The invention uses irradiation of keratin fibers via pulsed
light, i.e. light pulses. These pulses may be generated in various
ways, preferentially using a laser, but other sources, for example
a flash lamp, may be envisioned provided that they are able to
deliver pulses suited to the treatment to be performed.
[0065] The light used for the treatment according to the invention
may have a relatively short pulse duration and a relatively high
peak power.
[0066] The keratin fibers are, for example, exposed locally, at the
same place, to several successive pulses. Advantageously,
successive pulses make it possible to reduce the risk of damaging
the keratin fibers, since the fibers are then irradiated
gradually.
[0067] The pulse duration denotes the time for which the light
power reaching the keratin fibers is greater than or equal to half
of its peak power.
[0068] The pulse duration is, for example, between 10.sup.-16 s and
10.sup.-5 s and better still between 10.sup.-15 s and 10.sup.-7 s.
The duration is, for example, greater than 5.times.10.sup.-12 s or
less than or equal to 5.times.10.sup.-12 s.
[0069] The number of light pulses to which the same portion of
keratin fibers is exposed is controlled, for example, as a function
of the surface energy of the radiation that reaches the keratin
fibers, the color of the keratin fibers and the treatment to be
performed.
[0070] In a nonlimiting manner, in the case where one or more
firings are performed on the same portion of hair, the firing rate
is preferentially greater than or equal to 10 Hz and better still
100 Hz, or even greater than or equal to 200 Hz, 500 Hz or 1 kHz,
and preferentially less than 100 kHz.
[0071] In a nonlimiting manner, the dominant wavelength of the
light reaching the hairs may be between 300 nm and 10 000 nm and
preferentially between 400 nm and 2000 nm. The dominant wavelength
may be part of the visible, ultraviolet or infrared spectrum.
[0072] In a nonlimiting manner, various optical, absorbent or
dichroic filters may be used so as to filter the light irradiating
the fiber, for instance filters that screen out ultraviolet light
or colored filters for protecting the natural or artificial color
of the hairs. It will preferably be chosen to illuminate the hairs
with a light that is not absorbed by certain sensitive compounds of
the hairs. These colored filters make it possible, for example, to
remove or greatly reduce certain components of light that
correspond, for example, to the absorption band of hair dyes or to
other absorption bands.
[0073] The characteristics of the emitted light are, for example,
manually or automatically controlled, optical components being
intended, for example, to be changed or moved so as to modify the
focusing or the dominant wavelength of the light. The selection of
the wavelength of the light projected onto the fibers to be treated
is, for example, performed automatically or manually. A user can,
for example, manually change an optical component such as a lens or
a filter through which the light radiation passes during use.
[0074] A servomechanism may also be provided to perform automatic
control of irradiation parameters, for example by controlling one
or more optical components, this or these optical component(s)
being, for example, moved by means of actuators piloted by one or
more command signals. These command signals are transmitted, for
example, by the computing unit of the treatment system as a
function of data received from one or more sensors, for instance an
optical sensor or a camera that can detect different hair colors or
natures.
[0075] Automatic control may also be performed on the basis at
least of answers to a questionnaire concerning the hair of the
person to be treated.
[0076] The power supply of the irradiation device may be
autonomous, for example portable and integrated into a
handpiece.
[0077] In a nonlimiting manner, use may be made, to produce the
light used for the treatment, of "attosecond" lasers whose pulse
duration ranges from 10.sup.-18 to 10.sup.-15 sec, "femtosecond"
lasers whose pulse duration ranges from 10.sup.-15 sec to
10.sup.-12 sec or "picosecond" lasers whose pulse duration ranges
from 10.sup.-12 sec to 1 ns.
[0078] It is possible to use flash-pumped lasers, which generally
have a pulse duration of about a nanosecond, or diode-pumped
lasers, whose pulse duration generally ranges from one nanosecond
to about a hundred nanoseconds.
[0079] The irradiation device comprises, for example, a laser with
a cavity formed by two mirrors located on either side of a
broad-band amplifier material, for example based on
titanium-sapphire or based on ytterbium. The cavity may also be
formed by an optical fiber made of an amplifier material. The
irradiation device may comprise a mode-blocking device.
[0080] The irradiation device may comprise a lens associated with
the laser, with a digital aperture of between, for example, 0.1 and
1, such as a lens used for the reading of optical storage disks.
The irradiation device may also comprise a coupler for injecting
the pumping light and a coupler for extracting the laser pulses.
The pumping light is produced, for example, by a diode, but may
also be produced by a flash lamp or by another laser.
[0081] Irrespective of the light generator used, each of the
firings has, for example, a peak power of 1 MW to 1000 GW and
better still 1 MW to 100 GW.
[0082] The irradiation device uses, for example, a laser whose mean
electrical power is between 0.001 W and 50 W and which delivers,
for example, peak powers ranging from 1 MW to 100 GW.
[0083] The number of firings to which the treated portion is
subjected is, for example, between 1 and 10 000 firings and
preferentially between 5 and 1000 firings.
[0084] The light reaching the keratin fibers has, for example, a
fluence from about 1 to a few J/cm.sup.2, for example less than 5
J/cm.sup.2. The fluence may range, for example, from 0.1
mJ/mm.sup.2 to 50 mJ/mm.sup.2, for example as a function of the
yields, the pulse durations or the adjustments made as a function
of the hair type.
[0085] A user interface with, for example, a screen and one or more
selection keys may make it possible to select among various
operating modes and/or to modify the pulse durations, the energy
supplied per firing and/or the firing frequency.
[0086] Nonlinear optical components may be used to double or triple
the frequency or to spread out the spectrum of the light reaching
the treated fibers.
[0087] The irradiation device may comprise a device for collimating
the light beam and thus use a less powerful laser for an identical
irradiation energy, but which is nevertheless sufficient to perform
the desired hair treatment. The collimating device is, for example,
adjustable so as to adjust the light flux reaching the keratin
fibers. This adjustment is performed manually or automatically, for
example as a function of the color of the keratin fibers to be
treated or as a function of a desired degree of result. The
collimating device may comprise several lenses, which are
convergent and/or divergent.
[0088] The irradiation device may be used close to the hair or
transportation of the light to the transparent medium may be
performed. Various optical components may be used for transporting
the light, such as collimation optics, one or more mirrors and/or
optical deflectors and/or an optical channel such as one or more
optical fibers.
[0089] An optical deflector may serve to orient the path of the
light rays as a function of addressing data. The optical deflector
is piloted, for example, by the computing unit to deliver the light
beam onto the portion of the keratin fibers to be treated.
[0090] The irradiation device may also be equipped with means for
confining or absorbing light, for trapping the light and preventing
it from diffusing outside the treatment area.
[0091] The optical output may have any form, and may be single or
multiple. The irradiation device comprises, for example, a circular
optical output or an output in the form of one or more slits, which
may have various profiles.
[0092] The optical output may be in contact with the transparent
medium.
Treatment Process and System
[0093] The treatment process according to the invention may be
applied to a single hair, but preferably to a lock of hair
comprising, for example, between 100 and 10 000 hairs.
[0094] The process may be applied to a portion of this lock or to
several separate portions of this lock, or even to the whole lock.
The lock that is irradiated may comprise a single layer of
irradiated hair, but the treatment is preferably performed with
several superposed layers of hair, the treated thickness thus being
greater than that of one hair.
[0095] FIGS. 1a and 2a illustrate the treatment of a lock
comprising three superposed layers of hair, but, needless to say,
the invention is not limited to a particular number of layers or to
a particular regular arrangement of hairs within each layer, the
stacking of the hairs in a treatment area possibly being irregular
without the various stacked layers being clearly discernible.
[0096] In accordance with one aspect of the invention, at least one
hair H is in contact with a transparent medium M that has a
refractive index of greater than 1.3 and that contributes towards
delivering the light to the hair(s) to be treated.
[0097] FIG. 1b illustrates the possibility for the medium M of not
including all the thickness of the lock and of being in contact,
for example, with only the surface layers thereof.
[0098] FIG. 2b illustrates the possibility of all of the lock being
in contact with the transparent medium M.
[0099] The light is delivered to the hair by passing through an
entry face I of the medium M that advantageously has a predefined
shape, for example flat as illustrated in FIGS. 1b and 2b.
[0100] The entry surface of the medium through which the incident
light passes during a firing is, for example, between 10 000
.mu.m.sup.2 and 100 cm.sup.2.
[0101] The fact that the face I of entry into the medium M has a
predefined shape makes it possible to control the penetration of
light into the medium and thus to optimize the amount of light
reaching the hairs. It is also possible to prevent a hair from
being irradiated with a large amount of energy while it is not
immersed in the medium.
[0102] All the hairs of the first surface layer may thus be located
behind the entry surface I.
[0103] FIGS. 1a and 2a represent the outer surface of the medium M
with an irregular shape to illustrate the fact that the light entry
surface is not of predefined shape.
[0104] Many possibilities exist for giving the entry surface I a
predefined shape.
[0105] It is possible, for example, to flatten or level off the
medium so as to impose its shape on the entry face I, the levelling
or flattening possibly being performed, for example, manually or
automatically.
[0106] The user may, for example, move a treatment system member to
level the surface of the medium.
[0107] The shape of the surface for the entry of light into the
medium may also be defined with a transparent wall 10, in contact
with the medium M, as illustrated in FIGS. 3 and 4.
[0108] These figures show, very schematically and partially, a
treatment system 15 that comprises an optical channel 16 for
delivering light up to the transparent wall 10 in contact with the
medium M.
[0109] The hairs H are confined in a guide system 20 that at least
partially defines the treatment space 21 containing the medium M.
The thickness e of this treatment space 21 is, for example, between
1 mm and 5 mm, which can receive, for example, between 1 and 20
layers of hair, for example three layers.
[0110] The width L of the treatment space 21 is, for example,
between 5 mm and 30 mm.
[0111] The medium M present in the treatment space 21 may be
delivered therein in various ways.
[0112] For example, the medium M is deposited on the hairs before
they enter the treatment space.
[0113] As a variant, the treatment space is fed with transparent
medium via the guide system, for example via the sides of the canal
in which the hairs extend, for example via one or more orifices 26
that are in communication with a source of the fluid intended to
constitute the transparent medium.
[0114] Where appropriate, a recovery system, not shown, for
instance a basin, may be arranged so as to recover the medium that
flows via the longitudinal ends of the canal of the guide system,
via which the hairs enter and leave. These longitudinal ends may
optionally be provided with a sealing system, for example seals
between which the hairs pass.
[0115] The treatment system may be arranged to exert a pressure or
a tension on the hairs to be treated, so as to ensure good
inclusion of the hairs in the transparent medium M.
[0116] In the example of FIG. 3, the lock of hair is immobile
relative to the guide system 20. The transparent wall 10 can move
longitudinally relative to the guide system 20 to treat the lock
extending in the guide system.
[0117] On moving, the transparent wall 10 presses on the
transparent medium M, which ensures its planarity on contact with
the transparent wall 10, and the absence of air also makes it
possible to spread out the hairs present in the guide system.
[0118] The movement of the transparent wall 10, which defines the
optical output of the irradiation device, relative to the guide
system may be effected manually or, as a variant, automatically,
the treatment system comprising, for example, an actuator for
moving the optical output in a manner slaved to the emission of the
light pulses.
[0119] Optionally, the dispensing of the fluid intended to
constitute the transparent medium can be slaved to the forward
motion of the optical output, so as to make the dispensing of the
fluid coincide with the positioning of the optical output.
[0120] It is also possible, in another variant, to arrange for the
fluid not to be dispensed via the orifices of the guide system, but
via a part of the treatment system that comprises the optical
output. Preferably, the fluid is dispensed via at least one orifice
that is located upstream of the optical output with regard to its
direction of motion, in order for the fluid to have the time to
impregnate the hairs before the arrival of the light.
[0121] In one variant illustrated in FIG. 5, the optical output is
rigidly attached to a container 40 filled with liquid intended to
constitute the transparent medium. The treatment system 15
comprises a handpiece 42 on which is mounted a reservoir and which
supports the optical output.
[0122] The hairs may pass through a treatment space in which
emerges an orifice that is in communication with the reservoir.
[0123] The handpiece may be moved along the hairs.
[0124] The irradiation may take place automatically, as a function
of the movement, and/or may be controlled by the operator.
[0125] Needless to say, the invention is not limited to the
examples that have just been described.
[0126] The expression "comprising one" should be understood as
being synonymous with "comprising at least one", unless otherwise
mentioned.
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