WO2010069932A1

WO2010069932A1 - Spray head for a cosmetic product, device, and associated spraying method

Info

Publication number: WO2010069932A1
Application number: PCT/EP2009/067107
Authority: WO
Inventors: Nicolas Duru; Pascal Tierce
Original assignee: L'oreal
Priority date: 2008-12-15
Filing date: 2009-12-14
Publication date: 2010-06-24
Also published as: FR2939616B1; FR2939616A1

Abstract

The head comprises a surface (62) for actuating spraying and a transducer (50) capable of being excited into vibration by electrical excitation means and capable of transmitting its vibrations to the actuating surface (62). The actuating surface (62) has a plurality of distinct seats of vibration resonance.

Description

Spray head for a cosmetic product, device, and associated spraying method

The present invention relates to a spray head for a cosmetic product, of the type comprising:

- a surface for actuating spraying; and

- a transducer capable of being excited into vibration by electrical excitation means and capable of transmitting its vibrations to the actuating surface.

The head is intended to be mounted on a spray device. Such a device is intended especially for spraying at least one cosmetic product, for example a perfume, into the atmosphere and/or onto a user.

A "cosmetic product" is understood as being especially a product as defined in Council Directive 93/35/EEC dated 14th June 1993.

In order to spray such a product, it is generally known to use devices in which the product is projected under the effect of the pressure generated by a propellant of the aerosol type or alternatively by a pump actuated mechanically by the user. Such devices are not very convenient or potentially cause harmful or inflammable gases to be diffused into the atmosphere.

In order to remedy that problem there is known especially from EP-A-O 714 709 a device of the above-mentioned type which comprises piezoelectric means for spraying at least one liquid to the outside of the case constituting the device.

The device described in EP-A-O 714 709 comprises at least two separate perfume reservoirs and piezoelectric projection heads which allow one and/or the other of the perfumes to be conveyed selectively as desired by the user.

However, that document does not describe the structure of the control means that allow the selective diffusion of perfume to be obtained. Accordingly, it is an object of the invention to obtain a head for a device for spraying at least one product which offers a large variety of uses for the spraying of the liquid while remaining simple to manufacture and inexpensive.

To that end, the invention relates to a head of the type mentioned above, characterised in that the actuating surface has a plurality of distinct seats of vibration resonance.

The head according to the invention can have one or more of the following features, taken in isolation or in any technically possible combination(s): - the seats of vibration resonance are selectively actuatable.

"Selectively actuatable" means especially that a first seat of vibration resonance can be made to vibrate with an amplitude greater than that of a second seat of vibration, the first seat then exhibiting a vibration with a significant amplitude while the second seat simultaneously exhibits a vibration of low or zero amplitude, and, conversely, the second seat of vibration resonance can be made to vibrate with an amplitude greater than that of the first seat of vibration, the second seat then exhibiting a vibration with a significant amplitude while the first seat simultaneously exhibits a vibration of low or zero amplitude.

- the transducer has: - a first mode of vibration in which the transducer effects significant deformation of at least one first region of the actuating surface perpendicularly to the actuating surface in order to define a first seat of vibration resonance and effects slight or zero deformation of at least one second region of the actuating surface perpendicularly to the actuating surface, and - a second mode of vibration in which the transducer effects significant deformation of the second region perpendicularly to the actuating surface in order to define a second seat of vibration resonance and effects slight or zero deformation of the first region perpendicularly to the actuating surface;

- the actuating surface has a shape that is elongated according to a longitudinal axis; - a first seat of vibration resonance is situated substantially in the centre of the actuating surface, a second seat of vibration resonance being situated in the vicinity of the periphery of the actuating surface relative to the first seat of vibration resonance;

- the transducer has a peripheral portion of variable thickness along its periphery; - the transducer has a first peripheral portion formed from a first material, advantageously a ceramics material, and at least one second peripheral portion further comprising a second material, advantageously a metallic material;

- the transducer is coupled mechanically to the actuating surface to form a vibrating element;

- the transducer has substantially an elliptical shape, the first seat of vibration resonance being situated in the centre of the elliptical shape, the second seat of vibration resonance being situated opposite a geometric focus of the elliptical shape;

- the transducer has substantially a substantially rectangular shape.

The invention relates also to a device for spraying a product, characterised in that it comprises:

- a head as defined above;

- electrical excitation means for the transducer; - drive means for the excitation means, which drive means are capable of being switched selectively by a user between a rest state, a first state of selective excitation of a first seat of vibration resonance and a second state of selective excitation of a second seat of vibration resonance.

The device according to the invention can have one or more of the following features, taken in isolation or in any technically possible combination(s):

- in the first state of excitation, the drive means drive the excitation means in order to excite the transducer at a first frequency, and in the second state of excitation, the drive means for the excitation means drive the excitation means in order to excite the transducer at a second frequency that differs from the first frequency by at least 1 %;

- the device comprises:

- a body which delimits a liquid flow space, the actuating surface allowing the product present in the flow space to diffuse in spray form outside the body;

- the flow space opens outside the body via at least one spray opening; - the actuating surface closes off the liquid flow space to the outside at least partially, the or each spray opening opening into the actuating surface;

- the device comprises a fixed closure member which delimits the flow space to the outside, the or each spray opening being formed in the fixed closure member, the actuating surface being located opposite and at a distance from the fixed closure member;

- the flow space opens via at least one first spray opening situated opposite a first seat of vibration resonance and via at least one second spray opening situated opposite a second seat of vibration resonance, driving of the excitation means in the first state of excitation causing product to be sprayed through the or each first opening without significant spraying through the or each second opening, driving of the excitation means in the second state of excitation causing product to be sprayed through the or each second opening without significant spraying through the or each first opening; - the body delimits a first cavity which opens via the or each first spray opening and a second cavity which opens via the or each second spray opening, the first cavity and the second cavity being separated tightly in order to contain, respectively, a first liquid and a second liquid distinct from the first liquid; and

- the drive means comprise at least one selection member arranged on an outside surface of the body for selectively switching the drive means between the rest state, the first state of excitation and the second state of excitation.

The invention relates especially to a device for spraying a product, characterised in that it comprises: - a head as defined above;

- electrical excitation means for the transducer;

- drive means for the excitation means, capable of being selectively switched by a user between a rest state, a first state of selective excitation of a first seat of vibration resonance and a second state of selective excitation of a second seat of vibration resonance,

- the flow space opens via at least one first spray opening situated opposite a first seat of vibration resonance and via at least one second spray opening situated opposite a second seat of vibration resonance, driving of the excitation means in the first state of excitation causing product to be sprayed through the or each first opening without significant spraying through the or each second opening, driving of the excitation means in the second state of excitation causing product to be sprayed through the or each second opening without significant spraying through the or each first opening. The device can have the following features:

- in the first state of selective excitation of the first seat of vibration resonance, a first liquid is sprayed, while in the second state of selective excitation of the second seat of vibration resonance, a second liquid distinct from the first liquid is sprayed;

- the body delimits a first cavity which opens via the or each first spray opening and a second cavity which opens via the or each second spray opening, the first cavity and the second cavity being separated tightly in order to contain, respectively, a first liquid and a second liquid distinct from the first liquid.

The device so defined can have one or more of the features mentioned hereinbefore, taken in isolation or in any technically possible combination.

The invention relates further to a method of spraying a product by means of a device as defined hereinbefore, characterised in that it comprises the following steps:

- driving the drive means in order to bring the excitation means into the first state of excitation of the first seat of vibration resonance;

- vibration of the transducer according to a first mode of vibration in which the transducer effects the deformation of at least one first region of the actuating surface perpendicularly to the actuating surface in order to define the first seat of vibration resonance and effects slight or zero deformation of at least one second region of the actuating surface perpendicularly to the actuating surface;

- switching the drive means in order to bring the excitation means into the second state of excitation of the second seat of vibration resonance; - vibration of the transducer according to its second mode of vibration in which the transducer effects significant deformation of the second region perpendicularly to the actuating surface in order to define the second seat of vibration resonance and effects slight or zero deformation of the first region perpendicularly to the actuating surface.

The invention will be better understood upon reading the following description, which is given solely by way of example and makes reference to the accompanying drawings, in which:

- Figure 1 is a diagrammatic view in partial section according to a vertical plane of a first spray device according to the invention; - Figure 2 is a top view of the vibrating element of the device of Figure 1 ;

- Figure 3 is a partial perspective and cutaway view according to a mid-plane III of the vibrating element shown in Figure 2, in a first mode of vibration;

- Figure 4 is a view analogous to Figure 3 in a second mode of vibration; - Figure 5 is a view analogous to Figure 3 in a third mode of vibration;

- Figure 6 is a view analogous to Figure 3 in a fourth mode of vibration;

- Figure 7 is a view analogous to Figure 1 of a second device according to the invention;

- Figure 8 is a view analogous to Figure 2 of the vibrating element of a third device according to the invention; - Figure 9 is a view analogous to Figure 2 of the vibrating element of a fourth device according to the invention;

- Figure 10 is a view taken in section according to the mid-plane X of Figure 9;

- Figure 11 is a view analogous to Figure 2 of the vibrating element of a fifth device according to the invention; - Figure 12 is a view analogous to Figure 10 of the vibrating element of the device of Figure 11 ;

- Figure 13 is a perspective view of the vibrating element of a sixth device according to the invention, in a first mode of vibration;

- Figure 14 is a view analogous to Figure 13 in a second mode of vibration; - Figure 15 is a view of a detail of a seventh device according to the invention;

- Figure 16 is a partial perspective view of the spray head of an eighth device according to the invention;

- Figure 17 is a cutaway view according to a transverse plane of the head of Figure 16 in a first mode of vibration of the vibrating element; - Figure 18 is a view analogous to Figure 17 in a second mode of vibration of the vibrating element;

- Figure 19 is a view analogous to Figure 15 of a ninth device according to the invention;

- Figure 20 is a view analogous to Figure 15 of a tenth device according to the invention; - Figure 21 is a diagrammatic view of a variant of a liquid reservoir for use with a spray device according to the invention;

- Figure 22 is a view of a variant of means for conveying liquid to a vibrating element for a device according to the invention;

- Figure 23 is a view analogous to Figure 22 of a different means of conveying liquid; - Figure 24 is a view showing a first variant of drive means for the vibrating element of a device according to the invention;

- Figure 25 is a view analogous to Figure 24 of different drive means for the excitation means of the vibrating element of a device according to the invention.

In the following, the terms "upstream" and "downstream" are to be understood relative to the normal direction of flow of a fluid in a pipe.

The terms "upper" and "lower" are to be understood relative to the orientations adopted in the figures.

A first device 10 according to the invention is shown in Figures 1 to 6.

The first device 10 is intended to selectively project a first product 12, which is advantageously liquid, a second product 14, which is advantageously liquid, or, in a variant, a mixture of products 12 and 14, in the form of droplets of liquid into the atmosphere, in particular towards a user.

In this example, the first liquid 12 and the second liquid 14 are distinct liquids. They are formed, for example, by a cosmetic product, especially an odorous substance such as a perfume.

In a variant, the first product and/or the second product are formed by a gel.

The device 10 comprises a body 16 and a spray head 17, which comprises a vibrating element 18 for selectively spraying the first liquid 12 and the second liquid 14. The device 10 further comprises means 20 for electrical excitation of the vibrating element 18, and means 22 for driving the excitation means 20 by a user of the device 10.

The device 10 is capable of being grasped in the hand of a user so that it can be carried by the user.

To that end, the vibrating element 18, the excitation means 20 and the drive means 22 are carried by the body 16 in order to be displaced conjointly therewith. The body 16 comprises a case 24 which delimits an inside cavity 26, and reservoirs 28, 30 for liquid 12, 14, respectively, the reservoirs 28, 30 being contained in the inside cavity 26.

The inside cavity 26 opens to the outside of the case 24 via an opening 32 for receiving the vibrating element 18 and, advantageously, via at least one door (not shown) permitting access to the reservoirs 28, 30.

The first reservoir 28 and the second reservoir 30 each have an opening for the passage of liquid 12, 14 which extends at least partly opposite the vibrating element 18.

In this embodiment, the first reservoir 28 is separated from the second reservoir 30 by at least one partition wall 34 so that the liquid 12 contained in the first reservoir 28 is separated tightly from the liquid 14 contained in the second reservoir 30.

Each reservoir 28, 30 contains a member 36A, 36B for conveying liquid 12, 14 to the vibrating element 18 by capillarity.

In the example shown in Figure 1 , each conveying member 36A, 36B is formed by a wick of fibrous material which is immersed in the liquid 12, 14 and one end of which is in contact with the vibrating element 18.

Each wick defines a flow channel 38A, 38B for a liquid 12, 14, which channel is closed at its downstream end by the vibrating element 18.

In this example, the first reservoir 28 and the second reservoir 30 are removable relative to the case.

Accordingly, the reservoirs 28, 30 can be taken out of the case 24 and replaced by a different reservoir when they no longer contain sufficient liquid 12, 14. Referring to Figure 2, the vibrating element 18 has a shape that is elongated along a longitudinal axis B-B', in a plane perpendicular to a general axis A-A' of spraying of droplets of liquid to the outside of the case 24, the axis A-A' being vertical in Figure 1.

As is shown in Figure 2, the vibrating element 18 comprises a transducer formed by a piezoelectric member 50, and a grid 52 which is integral with the piezoelectric member 50 in order to be deformed thereby.

The piezoelectric member 50 extends at the periphery of the vibrating element 18 substantially in a horizontal plane in Figure 1. In this example, it is produced in one piece.

It comprises a peripheral collar 54 which defines a central opening 56.

The peripheral collar 54 is fixed to the case 24 at the periphery of the receiving opening 32.

The thickness of the collar 54 is at least twice the thickness of the grid 52. The collar 54 is made of a piezoelectric material such as a ceramics plate, especially a plate of zirconate (PZT), methaniobate (PB), barium titanate or zinc oxide.

As will be seen below, the piezoelectric material is capable of being deformed outside its rest plane when it is subjected to a voltage, the deformation especially being the result of torsion.

In the example shown in Figure 2, the piezoelectric member 50 has the shape of an ellipse which extends according to a longitudinal axis B-B'. The length of its major axis is at least 1.2 times greater than the length of its minor axis.

The grid 52 is formed by a plate 58 of small thickness, its thickness being at least twice as small, advantageously at least four times as small, as the thickness of the piezoelectric member 50. In this example, the plate 58 is attached beneath the piezoelectric member 50. The plate 58 has a contour analogous to that of the member 50. It closes the central opening 56 to the inside of the case 24.

In a variant, the grid 52 and the piezoelectric member 50 are integral so that the peripheral collar 54 and the plate 58 are made in one piece.

The thickness of the plate is, for example, less than 1 mm and from 10 μm to 100 μm.

The plate 58 defines an upper surface 60, which is fixed at its periphery beneath the collar 54, and a lower surface 62 for actuating spraying, which lower surface 62 is in contact with the first liquid 12 and with the second liquid 14 present in the capillary conveying members 36A, 36B.

Between its upper surface 60 and its lower surface 62, the plate 58 has a plurality of first through-openings 64 for spraying the first liquid 12 and a plurality of second openings 66 for spraying the second liquid 14.

As indicated hereinbefore, the lower surface 62 closes off each reservoir 28, 30 downstream. It is thus in contact with the liquids 12, 14, respectively, present in the conveying members 36A, 36B.

In this example, the partition wall 34 also bears against the lower surface 62 at least when the vibrating element 18 occupies a rest configuration.

The lower surface 62 accordingly comprises a first region 70 which is situated substantially in the centre of the plate 58 in the example shown in Figure 1 , opposite the first channel 38A for supplying first liquid 12. It comprises a second region 72 which is situated opposite the second channel 38B for supplying the second liquid 14, which in this example is situated in the vicinity of a focus F of the elliptical shape defined by the vibrating element 18. The first openings 64 are provided in the first region 70. They open at the top into the upper surface 60 and at the bottom into the lower surface 62 opposite the conveying member 36A.

Each first opening 64 has a maximum transverse dimension, advantageously a maximum diameter, taken perpendicularly to the axis A-A', of less than 100 micrometres and greater than 5 micrometres.

The number of first openings 64 is, for example, from 1 to 1000.

The second openings 66 are provided in the second region 72. They open at the top into the upper surface 60 and at the bottom into the lower surface 62 opposite the conveying member 36B.

Each second opening 66 has a maximum transverse dimension, advantageously a maximum diameter, taken perpendicularly to the axis A-A', of less than 100 micrometres and greater than 5 micrometres.

The number of second openings 66 is from 1 to 1000.

The first liquid 12 contained in the reservoir 28 is capable of being conveyed by the conveying member 36A in order to be discharged outside the body 16 solely through the first openings 64 situated in the first region 70.

Likewise, the second liquid 14 is capable of being conveyed by the conveying member 36B in order to be discharged outside the body 16 solely through the second openings 66 situated in the second region 72.

According to the invention, and as will be seen in detail below, the piezoelectric member 50 and the grid 52 are deformable between a rest configuration, at least one first mode of vibration of the vibrating element 18 for the selective deformation of the first region 70, shown in Figure 3, and at least one second mode of vibration of the vibrating element 18 for the selective deformation of the second region 72, shown in Figure 4. In this example, the piezoelectric member 50 and the grid 52 further have at least a third mode of vibration of the vibrating element 18, shown in Figure 5, for the selective deformation of the second region 72, and at least a fourth mode of vibration of the vibrating element 18, shown in Figure 6, for the joint deformation of the first region 70 and the second region 72.

In the rest configuration, the piezoelectric member 50 and the plate 58 extend substantially in a plane perpendicular to the axis A-A'.

In the first mode of vibration shown in Figure 3, which is obtained in this example by electrical oscillation of the piezoelectric member 50 at a first oscillation frequency f1 , the first region 70 situated in the centre of the plate has been deformed significantly relative to the rest configuration, perpendicularly to the surface 62 and parallel to the axis A-A'. The first region 70 accordingly forms a first seat of vibration resonance.

The second region 72, situated in the vicinity of a focus of the ellipse, has not undergone significant deformation and has experienced slight or no deformation parallel to the axis A-A'.

Within the scope of the present invention, "significant deformation" is understood as being a maximum deformation, taken parallel to the axis A-A', which is greater than more than 10% of the thickness of the plate 58, taken in the deformed region in the rest state.

"Slight or zero deformation" is understood as being a maximum deformation, taken parallel to the axis A-A' in a region that is not significantly deformed, which is less than at least 20%, or even at least 50%, of the maximum deformation, taken in a region that undergoes significant deformation.

These deformations can be measured, for example, by means of a Laser Doppler Vibrometer, which measures the amplitude and the speed of the vibrations by the Doppler effect and by optical interference. That apparatus allows vibration data to be measured at thousands of points on the surface 62 automatically, without any contact with the surface. The results are displayed, for example, in the form of a map. An example of a measuring device is marketed by the German company POLYTECH GmbH and comprises a laser of type OFV 056 "Vibrometer Scanning Head" with a OFV-3001 -SF6 controller.

In order to carry out such a measurement, the laser measuring head is arranged opposite the surface 62 to be measured. The device then analyses the surface 62 automatically.

In a variant, the deformations can be simulated by simulation software on the basis of a finite element analysis. Examples of software are marketed, for example, under the names Atila or Cosmosworks.

In the case of the Atila software, a simple three-dimensional mesh is produced on a quarter or half of the vibrating element 18 in order to reduce the number of elements and increase the accuracy of the calculation. On the cutting planes, the symmetry boundary conditions are applied so that the calculation determines only the modes having that symmetry.

In the case of the Cosmoswork software, the mesh is finer and is produced automatically by the software.

In that software, ceramics is considered to be an isotropic resilient material whose properties (Young's modulus, Poisson's coefficient, density) have been evaluated as a function of the orthotropic characteristics of the vibrating element 18.

In the second mode of vibration, which is shown in Figure 4, the second region 72 is deformed significantly, as defined above, while the deformation of the first region 70 is slight or zero. The second region 72 then defines a second seat of vibration resonance distinct from the first seat of resonance.

The second mode of deformation is obtained by exciting the piezoelectric member 50 at a second frequency f2 which is at least 2000 Hz greater than the first frequency f1. In the third mode of deformation, which is shown in Figure 5, the deformation of the first region 70 is likewise slight or zero, while the second region 72 is deformed significantly.

This mode is obtained by exciting the piezoelectric member 50 at a third frequency f3 which is at least 2000 Hz greater than the second frequency f2.

In the fourth mode shown in Figure 6, the deformation of the first region 70 and the deformation of the second region 72 are substantially equal and are significant relative to the rest state.

Accordingly, as will be seen below, in the first mode of vibration, the significant deformation of the first region 70 allows the liquid 12 present opposite the first region 70 to be sprayed through the first openings 64, while the slight or zero deformation of the second region 72 prevents a significant amount of liquid 14 being sprayed through the second openings 66.

The expression "significant amount" is understood as meaning not more than 5% of the amount sprayed through the first openings 64.

In the second and third modes of vibration, the significant deformation of the second region 72 allows the liquid 14 present opposite the second region 72 to be sprayed through the second openings 66, while the slight or zero deformation of the first region 70 prevents a significant amount of liquid 12 being sprayed through the first openings 64.

In the fourth embodiment, the significant deformation of the first region 70 and of the second region 72 simultaneously allows the liquids 12, 14 to be sprayed simultaneously through the first openings 64 and the second openings 66, respectively.

The piezoelectric member 50 accordingly vibrates at frequencies f1 , f2, f3 equal to the excitation frequency, in the ultrasonic range that is inaudible to a human user of the device. The excitation means 20 comprise a generator 80 of electric pulses of controlled frequency, a source 82 of electrical energy capable of supplying the generator 80, excitation electrodes 84 for the vibrating element 18, and a wire routing 86 which connects the pulse generator 80 to each electrode 84.

The generator 80 is capable of producing electric voltage pulses at least at the first frequency f1 and at the second frequency f2. It is accordingly capable of generating an electrical signal of given amplitude at that frequency f1 , f2 as a function of the state of excitation desired by the user, as received by the drive means 22.

The generator 80 is capable of carrying out frequency scanning around the selected frequency f1 , f2, for example over a range of frequencies extending to the maximum extent of 10% around the selected frequency f1 , f2. This allows the maximum amplitude of the significant deformation of the first region 70 or of the second region 72, respectively, to be maximised.

The electrical energy source 82 is, for example, a battery of low voltage, for example less than or equal to 1.5 volts, arranged in the case 24.

The electrodes 84 are applied above and below the peripheral collar 54. Each electrode 84 is connected to the generator 80 by a wire routing 86.

The drive means 22 are accessible to a user on an outside surface of the case 24.

In the example shown in Figure 1 , the drive means 22 comprise buttons 9OA, 9OB which are mounted in the case 24 for selectively switching the pulse generator 80 between a rest state, a first state of excitation of the first mode of vibration of the piezoelectric member 50 and a second state of excitation of the second mode of the piezoelectric member 50.

Accordingly, when the user does not press either of the buttons 9OA, 9OB, the generator 80 is in its rest state and does not deliver an electric pulse. When the user presses the first button 9OA, the generator 80 produces electric pulses at the first frequency f1 , which are transmitted to the piezoelectric member 50 via the routings 86 and the electrodes 84.

When the user presses the second button 9OB, the generator 80 produces electric pulses at the second vibration frequency f2, which are transmitted to the piezoelectric member 50 via the routings 86 and the electrodes 84.

The use of the first spray device 10 according to the invention will now be described.

Initially, the device 10 is at rest. The pulse generator 80 of the excitation means 20 does not deliver a variable voltage to the piezoelectric member 50. The member 50 and the grid 52 then occupy their rest configuration, in which the grid 52 remains substantially flat.

When the user wishes to atomise the first product 12, he presses the first button 9OA. The drive means 20 then switch the pulse generator 80 so that it produces, from the electrical energy source 82, electric pulses at the first vibration frequency f1 of the piezoelectric member 50. The electric pulses are transmitted to the piezoelectric member 18 through the routings 86 to the electrodes 84.

Under the effect of the voltage applied between the electrodes 84, the piezoelectric member 50 is deformed. On the basis of the excitation frequency f1 that it receives, the vibrating element 18 adopts the first mode of vibration described in Figure 3, in which the first region 70 is deformed significantly as described above, while the second region 72 is not deformed significantly.

Under the effect of the deformation of the first region 70, the liquid 12 present in the first flow channel 38A is sprayed through the first openings 64 to form a jet of droplets of first liquid 12, which is diffused according to the axis A-A' substantially perpendicular to the plane defined by the vibrating element 18 in its rest configuration. During spraying of the first liquid 12, the deformation of the second region 72 is not sufficient to produce a significant jet of second liquid through the second openings 66. The second liquid 14 therefore remains confined in the second reservoir 30.

If the user then wishes to spray a jet of second liquid 14, he releases the first button 9OA and presses the second button 9OB.

The drive means 22 then switch the pulse generator 80 so that it produces electric pulses at the second frequency f2 of excitation of the piezoelectric member 50.

The electrical signal at the second frequency f2 is then transmitted to the piezoelectric member 50 through the routings 86 and the electrodes 84.

The piezoelectric member 50 then adopts the second mode of vibration shown in Figure 4, in which the second region 72 is deformed significantly, without significant deformation of the first region 70.

The liquid 14 present in the second conveying member 36B is then sprayed through the second openings 66 to form a jet of droplets of liquid 14, which is diffused according to an axis A-A' substantially perpendicular to the plane defined by the vibrating element 18 in its rest configuration.

In a variant shown by dotted lines, the drive means 22 further comprise a third button 9OC capable of selecting a third state of excitation of the fourth mode of vibration of the piezoelectric member 50.

In this variant, when the third button 9OC is selected by the user, the first region 70 and the second region 72 are deformed significantly at the same time.

It is then possible to obtain two simultaneous jets of first liquid 12 and of second liquid 14.

The second device 100 shown in Figure 7 differs from the first device 10 in that it comprises a single reservoir 28 of first liquid 12. That reservoir contains a first member 36A for conveying the first liquid 12 to the first region 70 and a second member 36B for conveying first liquid 12 to the second region 72.

The single reservoir 28 extends opposite the first openings 64 and the second openings 66.

The geometric characteristics of the first openings 64 are different from those of the second openings 66.

Advantageously, the maximum transverse dimension of the first openings 64 is greater than the maximum transverse dimension of the second openings 66. It is thus possible selectively to modify the nature of the spray jet produced by means of the second device 100.

Accordingly, when the user drives the drive means 22 in order to switch the first mode of vibration, the first liquid 12 is sprayed through the first openings 64, as in the first device 10, which produces a first wetting jet with droplets having a first average size.

When the user operates the second button 9OB, it causes liquid to be sprayed through the second openings 66, which produces a second jet 104 of mist with a second average droplet size that is smaller than the average size of the droplets of the first jet 102.

Operation of the second device 100 is otherwise identical with that of the first device.

Figure 8 shows the vibrating element 18 of a third device according to the invention.

The vibrating element 18 of this third device has a substantially rectangular shape, with rounded corners. The third device is otherwise analogous to the first device or to the second device.

Figure 9 shows the vibrating element 18 of a fourth device according to the invention. Unlike the vibrating element 18 of the first device 10, this element comprises a circular piezoelectric member 50 produced from a peripheral collar 54 which has a variable composition over its periphery.

Accordingly, the peripheral collar 54 comprises at least one first peripheral portion 11 OA, 11 OB produced solely from ceramics material, and at least one second peripheral portion 112A, 112B produced from a ceramics material formed in one piece with the ceramics material of regions 110A, 110B and covered with a metal layer 114 located at a distance from the electrodes 84.

In the example shown in Figures 9 and 10, the collar 54 accordingly has two peripheral ceramics portions 110A, 110B which are located opposite one another relative to an axial mid-plane of the vibrating element 18, and two metal-covered ceramics peripheral portions 112A, 112B situated diametrically opposite one another.

Because the material constituting the piezoelectric member 50 is not homogeneous around the axis A-A', it is thus possible selectively to excite a first region 70 and a second region 72 when the user operates the drive means 22, as described above for the first device or for the second device.

Figures 11 and 12 show the vibrating element 18 of a fifth device according to the invention. This vibrating element has a generally circular shape in a plane perpendicular to the axis A-A'. However, the peripheral collar 54 has a variable thickness around the axis A-A'. Accordingly, the peripheral collar 54 comprises at least one first region 120A having a thickness greater than the thickness of a second region 120B.

In the example shown in Figures 11 and 12, the thickness of the first region 120A is substantially constant and is at least two times greater than the constant thickness of the second region 120B.

The regions 120A, 120B extend on either side of a mid-plane which passes through the axis A-A' of the member 18. Figures 13 and 14 show the vibrating element 18 of a sixth device according to the invention.

Contrary to the first device, this vibrating element 18 has a rectangular shape with angular corners.

Figure 13 shows a first mode of vibration of the vibrating element 18, in which at least one peripheral region 72 is deformed significantly while a central region 70 remains substantially without significant deformation.

Figure 14 shows a second mode of vibration, in which a central region 70 is deformed significantly while the peripheral region 72 remains without significant deformation.

Figure 15 shows a seventh device 120 according to the invention. Contrary to the first device, the grid 52 is not arranged in the vibrating element 18 but at a distance from and opposite the vibrating element 18.

The grid 52 is fixed to the case 24 around the opening 32. It remains substantially fixed during the deformation of the vibrating element 18.

The vibrating element 18 is mounted in the inside cavity 26 opposite the grid 52. It comprises a piezoelectric member 50 as described hereinbefore, and a deformable flexible membrane 122 which is attached to the piezoelectric member 50 and delimits the actuating surface 62 in contact with the first liquid 12 and with the second liquid 14.

Accordingly, the deformable membrane 122 and the grid 52 delimit, on either side of the partition wall 34, the first flow channel 38A for the first liquid and the second flow channel 38B for the second liquid.

The first openings 64 accordingly open into the first channel 38A opposite the first region 70 defined on the actuating surface 62. The second openings 66 open into the second channel 38B opposite the second region 72 of the actuating surface 60. As described hereinbefore, the piezoelectric member 50 is capable of being driven selectively by a user between a first mode of vibration for the selective deformation of the first region 70 and a second mode of vibration for the selective deformation of the region 72.

The selective vibration of each region 70, 72 causes corresponding vibration of the liquid opposite the region and the expulsion thereof through the respective openings 64, 66.

Figure 16 shows the spray head 17 of an eighth device 200 according to the invention, which is a variant of the seventh device 120.

As in the device 120, the grid 52 is fixed relative to the body 16 and the device 200 comprises a vibrating membrane 122 which delimits the actuating surface 62 located opposite and at a distance from the grid 52.

In the eighth device 200, the grid 52 and the vibrating membrane 122 have substantially the same shape and, in this example, have a rectangular shape.

Contrary to the seventh device, the piezoelectric member 50 comprises two separate parts 202A, 202B which face one another and are interposed between the grid 52 and the vibrating membrane 122. In this example, the separate parts 202A, 202B are substantially perpendicular.

Each part 202A, 202B accordingly bears on a respective lateral edge of the membrane 122 and on a lateral edge opposite the grid 52.

The separate parts 202A, 202B, the grid 52 and the actuating surface 62 delimit between them a flow space 38A for liquid 12, which opens via the respective openings 66, 64.

As described hereinbefore, the piezoelectric member 50 is capable of being driven selectively by a user between a first mode of vibration for selective deformation of the first region 70, shown in Figure 17, and a second mode of vibration for selective deformation of the second region 72, shown in Figure 18.

In the first mode of vibration, the selective deformation of the first region 70 causes the liquid 12 located opposite to vibrate and to be selectively sprayed through the first openings 64. In the second mode of vibration, the selective deformation of the second region 72 causes the liquid 12 opposite to vibrate and to be selectively sprayed through the second openings 66.

Part of a ninth device 210 according to the invention is shown in Figure 19. In contrast to the first device 10, the head 17 of this device comprises at least a first vibrating cone 212A for spraying the first liquid 12, which cone is associated with a first pump 212A, and a second vibrating cone 212B for spraying the second liquid 14, which cone is associated with a second pump 214B.

The first cone 212A and the second cone 212B are fixed to the upper surface 60 of the vibrating element 18 formed by a piezoelectric member 50 in the form of a ceramics plate, for example of elliptical shape, as described hereinbefore. The first cone 212A and the second cone 212B are arranged opposite the first region 70 and the second region 72, respectively.

The cones 212A, 212B are, for example, of the type described in DE 32 02 597.

Each cone 212A, 212B delimits on the inside a liquid flow channel 38A, 38B connected to the associated pump 214A, 214B.

Each cone 212A, 212B has at its free end an outer plate 216 into which there opens the channel 38A, 38B.

Each pump 214A, 214B is fixed to the lower surface 62 in a reservoir 28, 30. Each pump 214A, 214B is capable of pumping liquid 12, 14 in its reservoir and of conveying it to a plate 216 through a channel 38A, 38B. During operation, in the first mode of vibration of the vibrating element 18, the first region 70 is deformed significantly as described hereinbefore. At the same time, liquid 12 is conveyed to the plate 216 by the pump 214A. The liquid 12 present on the plate 16 then starts to vibrate and is atomised. Because the second region 72 undergoes only slight or zero deformation, the liquid 14 present on the plate 216 of the second cone 212B is not atomised significantly.

Conversely, vibration of the vibrating element 18 in its second mode produces significant deformation of the second region 72 and, consequently, atomisation of the liquid 14 present on the plate 216 of the second cone 212B.

A tenth device according to the invention is shown in Figure 20. The tenth device 220 according to the invention differs from the ninth device 210 in that the vibrating element 18 does not close off the liquid reservoirs 28, 30 present in the body 16. The actuating surface 62 formed on the vibrating element 18 is not in contact with the liquids 12, 14 that are to be sprayed.

Furthermore, the device 220 does not comprise a pump associated with each amplification cone 212A, 212B.

Each amplification cone 212A, 212B is solid and does not have an internal channel. It has, for example, the general shape of an I, of the type described in patent application WO2007/104859. Each cone 212A, 212B accordingly has a base 222 which bears on the actuating surface 62, and a slender intermediate portion 224 which projects substantially perpendicularly to the surface 62 as far as the plate 216.

As in the ninth device, the base 222 of a first cone 212A bears on the first region 70, and the base 222 of a second cone 212B bears on the second region 72.

The tenth device 220 comprises, for each cone 212A, 212B, a wick 230A, 230B for supplying liquid, which wick projects outside the body 16 from a reservoir 28, 30 to the plate 216 of the cone 212A, 212B on which it bears. Accordingly, the plate 216 of each cone 212A, 212B is supplied with liquid 12, 14 by the liquid flow channels 38A, 38B defined in each wick 230A, 230B. Operation of the tenth device 220 is otherwise analogous to that of the ninth device 210.

In a variant shown diagrammatically in Figure 21 , the conveying member 36A, 36B is formed by a porous member 130 which occupies substantially the whole of the inside cavity of the first reservoir 28 and/or of the second reservoir 30. Such a porous member is described, for example, in international application WO 2006/066671 of the Applicant.

In the variant shown in Figure 22, each conveying member 36A, 36B is formed by a substantially rigid capillary tube 140 which is urged resiliency towards the first region 70 and the second region 72, respectively, by way of a resilient wall 142, as described in French patent application no. 08 52470 of the Applicant.

In the variant shown in Figure 23, the conveying member 36A, 36B is formed by a bent wick having a base portion 150, whose axis is substantially perpendicular to the axis A-A', and an end portion 152 whose axis is substantially parallel to the axis A-A'. The end portion 152 bears against the actuating surface 62 in the first region 70 and in the second region 72.

Such an arrangement is described, for example, in French patent application no. 06 53 681 of the Applicant.

In another variant, the grid 52 is force-mounted in the piezoelectric member 18, as is described in French application no. 05 51374 of the Applicant.

In other variants, the or each reservoir 28, 30 can be equipped with a memory containing the diffusion characteristics of the product 12, 14, and the case 24 can comprise means for reading the memory, as described in French application no. 06 53681 of the Applicant.

Yet more generally, the case 24 can form part of a device comprising a screen and/or an analogue and/or digital tuner or a radio communication module, for example GSM, and/or of at least one reader and/or of a storage medium, such as, for example, an optical disk, a memory card, a magnetic strip or a hard disk. In another variant shown in Figure 24, the drive means 22 comprise a single actuating wheel 160 which can be displaced between a rest position, a first position for selection of the first state of excitation, and at least one second position for selection of the second state of excitation. The wheel is, for example, mounted for rotation in the case 24.

In another variant shown in Figure 25, the drive means 22 comprise a screen 170 which is integral with the case 24 and on which there are displayed indications representing the different modes of excitation of the piezoelectric member.

The means 22 then comprise at least one member for moving a selection cursor on the screen 170, and at least one member 174 for validating a selected state on the screen 170 for switching the excitation means 20.

By virtue of the invention which has just been described, it is possible to have available a device for diffusion of at least one liquid which permits a large variety of uses, either by varying the nature of the liquid that is diffused or by varying the characteristics of the jet of liquid that is diffused.

The use of a single piezoelectric member 50 which can be excited according to different modes of vibration in order selectively to deform different regions of a vibrating element 18 allows the device to be produced simply and inexpensively without having to duplicate the liquid spray means or the number of piezoelectric members.

Within the scope of the present invention, the expressions "comprising a" or "comprise a" must be understood as meaning "comprising at least one" or "comprise at least one", unless specified to the contrary.

In the case where the piezoelectric member 50 is elongated according to a longitudinal axis B-B', for example when it has an elliptical shape or a rectangular shape with rounded or angular corners, the length of each second region 72 and the length of the first region 70, taken along the axis of elongation B-B', are each especially less than 1/4, advantageously from 1/20 to 1/4, of the maximum length of the actuating surface 62, taken opposite the central opening 56 delimited by the piezoelectric member 50.

Furthermore, each second region 72 extends perpendicularly to the axis B-B' over a width of from 1/20 to 1/4 of the maximum width of the actuating surface 62, taken opposite the central opening 56. Each second region 72 extends at an angle about the axis A-A' over an angular extent of less than 90° and advantageously less than 30°.

Each first region 70 and each second region 72 is thus centred about a seat of resonance, over an area less than 10% of the total area of the actuating surface 62 taken opposite the central opening 56.

This produces extremely selective spraying of the liquids 12, 14 contained in the device.

Claims

1. Device (10; 100; 120) for spraying a cosmetic product (12, 14), of the type comprising: - a head (17) for spraying a cosmetic product (12, 14), of the type comprising:

• a surface (62) for actuating spraying;

• a transducer (50) capable of being excited into vibration by electrical excitation means and capable of transmitting its vibrations to the actuating surface (62); the device comprising: - means (20) for electrically exciting the transducer (50);

- means (22) for driving the excitation means (20); characterised in that the actuating surface (62) has a shape that is elongated according to a longitudinal axis (B-B'), and has a plurality of distinct seats of vibration resonance, the drive means (22) being capable of being switched selectively by a user between a rest state, a first state of selective excitation of a first seat of vibration resonance and a second state of selective excitation of a second seat of vibration resonance.

2. Device accord ing to claim 1 , characterised in that the seats of vibration resonance are selectively actuatable.

3. Device according to claim 1 or 2, characterised in that the transducer (50) has:

- a first mode of vibration in which the transducer (50) effects significant deformation of at least one first region (70) of the actuating surface perpendicularly to the actuating surface (62) in order to define a first seat of vibration resonance and effects slight or zero deformation of at least one second reg ion (72) of the actuating surface perpendicularly to the actuating surface (62), and

- a second mode of vibration in which the transducer (50) effects significant deformation of the second region (72) perpendicularly to the actuating surface (62) in order to define a second seat of vibration resonance and effects slight or zero deformation of the first region (70) perpendicularly to the actuating surface (62).

4. Device according to any one of the preceding claims, characterised in that a first seat of vibration resonance is situated substantially in the centre of the actuating surface (62), a second seat of vibration resonance being situated in the vicinity of the periphery of the actuating surface (62) relative to the first seat of vibration resonance.

5. Device according to any one of the preceding claims, characterised in that the transducer (50) has an elliptical shape or a rectangular shape with angular or rounded corners.

6. Device according to any one of the preceding claims, characterised in that the transducer (50) has a peripheral portion (54) of variable thickness along its periphery.

7. Device according to any one of the preceding claims, characterised in that the transducer (50) has a first peripheral portion (110A, 1 10B) formed from a first material, advantageously a ceramics material, and at least one second peripheral portion (112A, 112B) further comprising a second material, advantageously a metallic material.

8. Dev i ce ( 1 0 ; 1 00 ; 1 20 ) a cco rd i n g to a n y on e of the preceding claims, characterised in that, in the first state of excitation, the drive means (22) drive the excitation means (20) in order to excite the transducer (50) at a first frequency, and in that, in the second state of excitation, the drive means (22) for the excitation means (20) drive the excitation means (20) in order to excite the transducer (50) at a second frequency that differs from the first frequency by at least 1 %.

9. Device (10; 100; 120) according to any one of the preceding claims, characterised in that it comprises: - a body (16) which delimits a liquid flow space (38A, 38B), the actuating surface (62) allowing the product present in the flow space (38A, 38B) to diffuse in spray form outside the body (16).

10. Device (10; 100; 120) according to claim 9, characterised in that the flow space (38A, 38B) opens outside the body (16) via at least one spray opening (64, 66).

1 1 . Device (10; 100) accord ing to claim 10, characterised in that the actuating surface (62) closes off the liquid flow space (38A, 38B) to the outside at least partially, the or each spray opening (64, 66) opening into the actuating surface (62).

12. Device (120) according to claim 10, characterised in that it comprises a fixed closure member (52) which delimits the flow space (38A, 38B) to the outside, the or each spray opening (64, 66) being formed in the fixed closure member (52), the actuating surface (62) being located opposite and at a distance from the fixed closure member (52).

13. Device (10; 100; 120) according to any one of claims 9 to 12, characterised in that the flow space (38A, 38B) opens via at least one first spray opening (64) situated opposite a first seat of vibration resonance and via at least one second spray opening (66) situated opposite a second seat of vibration resonance, driving of the excitation means (20) in the first state of excitation causing product to be sprayed through the or each first opening (64) without significant spraying through the or each second opening (66), driving of the excitation means (20) in the second state of excitation causing product to be sprayed through the or each second opening (66) without significant spraying through the or each first opening (64).

1 4. Device ( 1 0 ; 1 00 ; 1 20 ) accord i ng to a ny on e of the preceding claims, characterised in that the drive means (22) comprise at least one selection member (9OA, 9OB, 90C) arranged on an outside surface of the body (16) for selectively switching the drive means (22) between the rest state, the first state of excitation and the second state of excitation.

15. Method of spraying a product (12, 14) by means of a device (10; 100; 120) according to any one of the preceding claims, characterised in that it comprises the following steps:

- driving the drive means (22) in order to bring the excitation means (20) into the first state of excitation of the first seat of vibration resonance;

- vibration of the transducer (50) according to a first mode of vibration in which the transducer (50) effects deformation of at least one first region (70) of the actuating surface perpendicularly to the actuating surface (62) in order to define the first seat of vibration resonance and effects slight or zero deformation of at least one second region (72) of the actuating surface perpendicularly to the actuating surface (62); - switching the drive means (22) in order to bring the excitation means (20) into the second state of excitation of the second seat of vibration resonance;

- vibration of the transducer (50) according to its second mode of vibration in which the transducer (50) effects significant deformation of the second region (72) perpendicularly to the actuating surface (62) in order to define the second seat of vibration resonance and effects slight or zero deformation of the first region (70) perpendicularly to the actuating surface (62).