EP3178344A1 - Cladding element with variable colours - Google Patents

Abstract

The present invention relates to a casing element (1) for portable object comprising a support on which is arranged a first material, said first material being selected adapted to reflect different visible wavelengths depending on the applied stress.

Description

The present invention relates to a portable object covering element comprising a support on which a first material is arranged, said first material being selected capable of selectively reflecting different visible wavelengths as a function of the applied stress.

BACKGROUND TECHNOLOGY

There are known portable objects such as watches that are equipped with colored trim elements. In general, the trim elements are colored with a particular color or pattern and this coloration is final.

However, there is a need for a watch with a trim element whose color may vary. Such a need comes from the desire of consumers to be able to change the color of their watch or portable object according to desires or mood.

An obvious solution is to provide accessories such as telephone shells or spare parts that can be easily replaced by the user.

However, this solution has the disadvantage that it becomes necessary for users to have a quantity of spare parts in stock, these parts can be lost and it becomes necessary to renew the stock at each watch or phone change.

Another solution is to use pigments whose color may vary, these pigments may be photochromic or thermochromic. These pigments are incorporated in an ink or directly into the material forming the covering element. A change temperature or brightness is then sufficient to change the color of the trim element.

A disadvantage here is that this configuration is not controllable. Indeed, these pigments react to specific values of temperature or brightness so that the consumer has little influence on these elements, it is dependent.

There is therefore a need for a trim element whose color variation is controllable.

SUMMARY OF THE INVENTION

The invention relates to a cladding element that overcomes the aforementioned drawbacks of the prior art by providing a portable object cladding element that allows a controllable color variation.

For this purpose, the object of the invention is to provide a portable object covering element comprising a support on which a first material is arranged, said first material being chosen able to selectively reflect different visible wavelengths as a function of the stress applied, said dressing element further comprising a device for modifying the stress applied to said first material.

This invention advantageously has to have a trim element that can see its color be changed without having to apply a coat of paint or without having to add a colored hull.

In a first advantageous embodiment, the support and the device for modifying the stress applied to said first material are one and the same piece.

In a second advantageous embodiment, the support is a bistable metal strip coated with said first material.

In a third advantageous embodiment, the device making it possible to modify the stress applied to said first material uses a second material able to see its varied volume as a function of a physical quantity, said second material being associated with a flexible element carrying the first material. material.

In a fourth advantageous embodiment, the support comprises at least one hollow closed by a film provided with the first material and forming a housing, said housing accommodating a capsule composed of two integral half-shells filled with said second material.

In a fifth advantageous embodiment, the support comprises at least one hollow closed by a film provided with the first material and forming a housing in which a capsule-piston system and the material are placed, said capsule-piston system consists of a half-shell and a piston so that the change in the volume of the second material causes a displacement of the piston.

In a sixth advantageous embodiment, each capsule is filled with said second material, which may be different from one capsule to another.

In another advantageous embodiment, each recess is filled with said second material, which may be different from one housing to another.

In another advantageous embodiment, the support is formed by at least two integral parts fixed together by their periphery so as to leave a gap between these two parts, at least one of the two parts being flexible and carrying said first part. material, said space forming the recess containing the second material.

In another advantageous embodiment, the support formed by the at least two parts further comprises at least one structure extending between the two parts to delimit at least two zones, each zone may contain a pocket.

In another advantageous embodiment, each zone contains a second specific material.

In another advantageous embodiment, the device for modifying the stress applied to said first material comprises a plastic bag connected to a pump system for inflating / deflating the bag, said pump system comprising a hollow bell provided with a hole for filling the air of the bell and a check valve having a pair of sheets of plastic material each welded to a wall of the pump, said sheets being substantially U-shaped folded and arranged one relative to each other to allow air to pass only in the direction of the pocket, said device being associated with a flexible member carrying the first material.

In another advantageous embodiment, the support is formed by at least two parts fastened together by their periphery so as to leave a gap between them, said space making it possible to house the pocket, one of the parts forming the strand being provided with an opening for the pump system to be inserted and accessible.

In another advantageous embodiment, at least one of the two parts is flexible and carries the first material.

In another advantageous embodiment, the at least one of the two parts is perforated, the first material being supported by the pocket as a flexible element and visible through the ajourage.

In another advantageous embodiment, the support is formed by at least two integral parts fixed together by their periphery so as to leave a gap between these two parts, at least one of the two parts being flexible and carrying the first part. material, said space forming the pocket of the pump system, one of the parts forming the strand being provided with an opening for the pump system to be arranged therein.

In another advantageous embodiment, said first material is in the form of a film deposited on said support.

In another advantageous embodiment, the flexible element is constituted at least in part by the first material.

In another advantageous embodiment, the flexible portion is formed at least in part by the first material.

The invention further relates to a portable object comprising a housing closed by a bottom and a cover, characterized in that said portable object comprises at least one covering element according to one of the preceding claims.

In an advantageous embodiment, said portable object is a timepiece comprising a case formed by a middle part closed by a bottom and an ice, and a bracelet fixed to the middle part via two pairs of horns, said bracelet being provided with at least one strand of bracelet, and in that the dressing element is chosen to be arranged in the list comprising the middle part, the bezel, the crown, a pusher, the bottom, the bracelet and the buckle.

In another advantageous embodiment, said timepiece further comprising a clockwork providing a time information has display means comprising a dial, said dial being part of the list in which the dressing element is chosen.

BRIEF DESCRIPTION OF THE FIGURES

• les figures 1 et 2 représentent de manière schématique un objet portable selon la présente invention ;
• les figures 3a, 3b et 3c représentent de manière schématique un premier mode de réalisation de l'élément d'habillage selon la présente invention ;
• les figures 4a à 8 représentent de manière schématique un premier mode d'exécution d'un second mode de réalisation de l'élément d'habillage selon la présente invention ;
• les figures 9 à 13 représentent de manière schématique un second mode d'exécution d'un second mode de réalisation de l'élément d'habillage selon la présente invention ;
• les figures 14 et 15 représentent de manière schématique une version de l'élément d'habillage selon la présente invention dans lequel ledit élément d'habillage est un cadran;

The advantages of such a covering element will become clear from reading the following description and examining the drawing which illustrates it by way of example and in which:

• the Figures 1 and 2 schematically represent a portable object according to the present invention;
• the Figures 3a, 3b and 3c schematically represent a first embodiment of the cladding element according to the present invention;
• the Figures 4a to 8 schematically represent a first embodiment of a second embodiment of the cladding element according to the present invention;
• the Figures 9 to 13 show schematically a second embodiment of a second embodiment of the cladding element according to the present invention;
• the Figures 14 and 15 schematically represent a version of the cladding element according to the present invention wherein said cladding element is a dial;

DETAILED DESCRIPTION

The present invention relates to a covering element 10 of a portable object 1. Said portable object may be for example a timepiece or watch 1. A conventional portable object comprises a case closed by a bottom and a cover and comprises a device enclosed in the case. Of course, such a portable object may be a telephone or a computer or a touch pad or a jewel such as a bracelet. It can also be a fashion accessory, such as a bag or glasses.

In the case where the portable object is a timepiece, the timepiece 1, visible to Figures 1 and 2 is, for example, a wristwatch comprising a case 2. This case 2 is formed by a middle part 20 closed by a bottom 21 and a mirror 22. The timepiece also comprises a bracelet 3. The latter is attached to the caseband by example via two pairs of horns 24 at the middle. The bracelet 3 may consist of two strands of bracelet, each strand being attached to a pair of horns and connected to the other strand via a clasp. The timepiece further comprises a mechanical or electronic watch movement providing a time information to display means 4. These display means comprise for example a dial 41 and needles 42 or disks 43 or an LCD screen 44 .

The covering element comprises a frame 12 also called a support and made of a metallic or plastic material. According to the invention, the covering element 10 uses a first material M1 capable of selectively reflecting different visible wavelengths according to the stress applied to it. Indeed, it is known materials capable of creating so-called structural colors. These materials are composed of at least two elements with different indices of refraction and alternating periodically. The size of the elements is of the order of magnitude of the wavelengths of the light so that phenomena of optical interference (constructive and destructive waves) are created which lead to the selective reflection of certain wavelengths. . The interference phenomena and therefore the reflected colors depend on the size of the periodic grating and the refractive indices of the at least two selected elements. In nature, there are several examples of structural colors. We can mention: butterfly wings, opals.

This type of material (called photonic crystals or opal materials) can also be synthesized by techniques known to the human being. art. Synthetic photonic crystals are generally manufactured by assembling in an orderly fashion mono-dispersed and bi-material spheres (with 2 different refractive indices at the core and at the periphery).

1. 1) par cristallisation, sédimentation, évaporation d'une suspension colloïdale (la technologie est notamment utilisée dans les encres P-Ink® et Elast-Ink®)
2. 2) sous l'effet d'un champ électrique (comme décrit par Baumberg Advanced Engineering Materials 2013, p 948 ),
3. 3) sous l'effet de forces de cisaillement par extrusion (comme décrit par Baumberg Stretching the imagination, Textiles, issue 4, 2009, 8-10 et US 2013/0288035 , Manufacture of composite optical materials).

The ordered network of spheres can be realized:

1. 1) by crystallization, sedimentation, evaporation of a colloidal suspension (the technology is used in particular in P-Ink® and Elast-Ink® inks)
2. 2) under the effect of an electric field (as described by Baumberg Advanced Engineering Materials 2013, p 948 )
3. 3) under the effect of extrusion shear forces (as described by Baumberg Stretching the imagination, Textiles, issue 4, 2009, 8-10 and US 2013/0288035 , Manufacture of composite optical materials).

The periodic network thus formed is then fixed by UV polymerization.

A second method of manufacturing photonic crystals is to create "pads" of nanometric size on flexible thin film (typically a sheet of PDMS). Researchers at the University of California Berkeley thus fabricated, by lithography techniques, rows of silicon pixels, which they then encapsulated in 2 sheets of PDMS (Flexible photonic metastructures for tunable staining, Optical Letters, 2015, p255). lead to a thin and flexible film that can change color at will under the effect of small deformations.

Indeed, when a material with a structural color is flexible or deposited on a flexible support, the periodic network can then be modified by changing the geometric dimensions of the material and it is then possible to obtain a material with structural colors that change. in a controlled manner when the material is mechanically stressed. These geometric dimensions are modified by applying a stress on said material. These constraints can be a stretch, a compression, twisting, pinching or any other constraint allowing a modification of the shape and / or dimensions of the material.

This first material M1 may then be in the form of a film of varying thickness or may be directly integrated into the substrate forming the covering element 10. In the case of a film, a first configuration allows the first material M1 to understand only a film or a so-called opal band obtained by the previously described techniques. In a second configuration, said first material M1 comprises the so-called opal film assembled on a flexible film. In a third configuration, said first material M1 comprises the opal film encapsulated in two flexible films. Flexible films are preferentially PDMS films or thermoplastic films, preferably thermoplastic polyurethane films

Therefore, the covering element 10 according to the invention must be provided, in addition to the support 12, a device 14 for applying a stress on the first material M1 to make it change color.

In a first embodiment, the covering element 10 is configured so that the support 12 and the device 14 for applying a stress on the first material to make it change color are one and the same element. It is then understood that the support is adapted, by its characteristics, to be manipulated so as to generate a mechanical stress on the first material M1.

According to one embodiment, the dressing element 10 is a strap 30 called "slap strap" or "slap band" in the English version. Such a bracelet 30 is composed of a bistable metal strip 32 acting as a support 12. The bracelet 30 can be flattened by tensioning the bistable metal strip 32 and then wrapped around the wrist again slamming the bracelet. This bistable metal strip 32 can then be coated with a protective layer 34. This protective layer 34 can be a molded plastic material or a film or ink that hardens to improve the aesthetics as visible in the figure 3a .

Advantageously according to this first embodiment, the first material M1 is arranged on this bistable metal strip.

In a first configuration, the first material is arranged to cover the entire surface of the bracelet 30. The first material M1 may then be in the form of a film of varying thickness that can be glued and / or sewn and / or assembled by gluing, ultrasonic welding, laser welding, infrared or extruded welding directly on the bistable metal strip 32 as visible in FIG. figure 3a or overmolded on the support 12. A protective layer 34 (varnish or thermoplastic) may optionally be applied on top. The first material M1 may then be placed either on the metal strip 32 or on the protective layer 34 of the bistable metal strip 32 as visible in FIG. figure 3b .

In a second preferred configuration, for reasons of ease of process, said material M1 is deposited on the strap 30 and then overmolded with a transparent thermoplastic TPU type.

In a third preferred configuration, for ease of process, said first material M1 comprises an opal film encapsulated in 2 transparent thermoplastic films (TPU type) and the material M1 is assembled to the bracelet by thermo-welding techniques.

In another configuration, the first material M1 is visible in certain specific places on the bracelet. For example, the first material M1 is placed on the bistable metal strip (sewn, glued, molded, assembled or extruded) then a second layer 35 (leather, thermoplastic, ...) perforated is placed so as to let appear first M1 material as visible to the figure 3c .

Thus, when the bistable metal strip 32 passes from one state to another that is to say from the state in which the metal strip is energized to the state in which the metal strip 32 does not is not energized and is wound up, a stress variation occurs on the metal strip. This variation of stress is transmitted to the first material M1. However, the first material M1 is able to reflect different wavelengths according to the stress applied to it. Therefore, when the slap strap 30 passes from one state to another, the variation of stress allows the first material M1 to reflect different wavelengths and thus to have a bracelet having different designs depending on whether it is coiled or not.

In a second embodiment, the support 12 and the device for applying a stress 14 to the first material M1 to make it change color are dissociated and the application of the stress to the first material is done through a material M2 able to see its volume vary according to a physical quantity, this physical quantity may be the temperature. More preferably, the material M2 is a liquid with a boiling point at atmospheric pressure of between 0 and 60 ° C. Under these conditions, when applying to the cladding element a temperature above the boiling point of M2, the material M2 goes into the gas phase and thus sees its volume increase. For example, the material M2 is ethyl chloride, butane, propane or a mixture of these compounds.

In a first embodiment, the support 12 comprises at least one recess 40. This at least one recess 40 is used to place a piston capsule system 43 and the material M2. This system of capsule-piston 43 sealed to the material M2 consists of a half-shell 44 and a piston 45 as visible to Figures 4a and 4b . The recess 40 is closed by a film 42 made of the material M1 or carrying the material M1. Therefore, as the temperature increases, the volume of the material M2 increases and acts on the piston 45. The piston 45 has a surface outer round which comes into contact with the film of said material M1 when the piston is in the up position. In this way, when the piston 45 is pushed by the material M2, it stretches the M1 material which then changes color.
The piston capsule 43 thus formed is then placed in a recess 40 of the covering element. This piston capsule 43 may be glued, driven, welded, screwed or crimped into the recess to be maintained. In a preferred embodiment, the covering element is incorporated in a thermoplastic component of the portable object (for example a bracelet, a dial, a watch case, etc.) and the thermoplastic component of the portable object carrying the cladding element 1 is directly overmolded on the piston capsule 43 thus forming the recess 40. In this case, a very good adhesion between the cladding element and the portable object to which it is integrated is obtained.

In an alternative configuration, said first material M1 comprises an opal film encapsulated in 2 transparent thermoplastic films (TPU type) and the material M1 is assembled for example by heat-sealing or by gluing.

This configuration advantageously makes it possible to make recesses 40 each accommodating a piston capsule 43 as visible in FIG. figure 4c these capsules may comprise specific and different M2 materials.

In this embodiment, the color variation of the material M1 capable of reflecting different wavelengths according to the stress applied to it is possible. Indeed, the material according to the invention is able to reflect different wavelengths according to the applied stress so that, for the same material, a difference in stress implies a different color variation.

To do this, a first solution consists in modifying the dimensions: length, volume of the piston capsule 43 or hollow 40. These modifications of the dimensions then cause a different response to the stress applied by the expansion of the material M2.

A second solution consists in using different variants of the material M2, each variant having a different coefficient of expansion. This solution makes it possible to have, for capsules 43 or a recess 40 of the same size, different color variations since the material M2 will be different.

A third solution is to use different materials for the embodiments of the membrane 42. Indeed, using materials each having different deformation properties, it is ensured that the stress applied to the material M1 will be different and therefore the variation of color will be different. It may also be provided to have, for each piston capsule 43, a specific material M1.

These possibilities then make it possible to produce a covering element 1 provided with a multitude of zones using this first material M1, the different zones being able to have characteristics allowing different color variations.

In a second embodiment, the recess 40 is used to accommodate a capsule 43 'provided with two half-shells 44' of flexible material as visible at Figures 5a and 5b . This capsule 43 'is then fixed in the recess by bonding or heat-sealing one of the half-shells 44'. This capsule 43 'is also arranged to be filled with a material M2 which expands as a function of a physical quantity such as temperature or pressure. The hollow 40 is closed by a film 42 'made with the material M1. Therefore, when the temperature increases for example, the material M2 in the capsule expands and deforms the half-shell 44 '. This half-shell 44 'in turn constrains the film 42'. This constraint deforms the film 42 'and therefore the material M1 reflects another wavelength. It may be provided to have several capsules 43 'per recess 40 as visible in FIG. figure 5c .

In an alternative to this second embodiment, the covering element 10 is itself used as a capsule 43 '. In a non-limiting example, the covering element will be a strand 31 or a bracelet link 3.

The bracelet strand is then composed of two assembled strips 310 together. This assembly is made so that the two strips 310 are fixed by their periphery so that the interior space 312 can serve as a cavity. This cavity 312 cleverly accommodates therein a pocket containing a material M2 that expands as a function of a physical quantity such as temperature or pressure.

Advantageously according to the invention, one or both strips 310 forming the strand 31 of bracelet 3 bear the material M1 capable of reflecting different wavelengths according to the stress applied to it. This first material M1 is arranged on one and / or the other of these strips in the form of a film or a strip or by directly forming part of the material forming said strip or strips 310 as visible in FIG. figure 6 .

Thus, when for example the temperature varies, the material M1 reacts and expands or contracts causing a deformation of the band or bands forming the bracelet strand. This deformation is therefore communicated to the first material M1 which, under the effect of this applied stress, sees its structure change and reflect different wavelengths as visible in FIG. figure 7 .

In an advantageous variant, the strap strand 31 comprises stiffening structures 313 as visible in FIG. figure 8 . These stiffening structures are arranged between the two strips 310 forming the strand and extend longitudinally or transversely relative to said strand. These structures make it possible to increase the torsional strength of the bracelet strand. These structures 313 are in the form of at least one wall 314 attached to the two strips. This configuration allows said walls to delimit different zones 315. For example, by having two transverse walls, three separate zones are created in the bracelet strand. Cleverly according to this variant, these zones can each be filled with a pocket containing a separate M2 material. This configuration makes it possible to have the band or bands forming the strand which deform irregularly, the material M2 of each distinct zone reacting differently.

Of course, it may be provided that the constituent strips of the bracelet strand is made of different materials. This advantageously makes it possible to have a material having more advantageous deformation characteristics for the strip carrying the first material. This causes said strip to become more easily deformable, resulting in better reactivity to the expansion of the second material M2.

In a third embodiment, the application of the stress to the first material M1 is via a mechanical device 14. This mechanical device is arranged to apply, at the request of the user, a constraint on the first material and thus modify its dimensions and / or its shape.

For this third embodiment, the device 14 for applying a stress on the first material is a pump device 140. Such a device is similar to that of the patent. US 5,113,599 deposited by Reebok®. Such a device schematically consists of a pocket 141 of plastic material provided with a pumping system 142. Such a pumping system 142 comprises a pump 143 and an exhaust valve 144 for inflating and deflating the pocket 141 of plastic material. A pump 143 used consists of a hollow bell 143a provided with a hole 143b for filling the air with the bell. The pump may also be provided with a non-return valve 145 using a pair of sheets 145a of plastic material which can be welded via a weld spot, to a wall of the pump 143. These sheets are folded substantially U-shaped and allow air to flow only in the direction of the arrow from the pump to the pocket.

To release air from the pocket, an outlet or exhaust valve 144 is used. The outlet valve as shown on the figure 9 may comprise a piston 144a having a spring 144b which biases the piston in the closed position. A flange 144c around the periphery of the piston rod 144a prevents air from leaking between the piston and the outlet fitting because the flange is urged into the closed position and in contact with said fitting. To release air from the pocket 141, the piston is depressed by the user so that air escapes around the piston rod.

This pump system 142 can then be directly arranged at the pocket 141 or be dissociated and connected to said pocket via a channel. The direct arrangement at the pocket 141 or at the channel is feasible by independently manufacturing the pump system 142 on a plastic base. This plastic base will be welded or glued on the pocket or the channel, these being provided with an opening as visible in the figure 9 .

In a first embodiment alternative visible to the figure 10 , the covering element 1 and the pocket 141 form only one element.

In a non-limiting example, the covering element 1 is a strand 31 of bracelet 3. Such a strand, as described above, comprises two strips 3100 made integral and forming a hollow space 3102 therebetween. This hollow space 3102 then forms an air pocket. One of the two bands 3100, preferably the band that the user will see while carrying the portable object, will be provided with the pump system 142 as described.

For this, one of the two bands 3100, preferentially the band that will be visible to the user, will be equipped with an opening 3103. This opening 3103 is provided for the installation of the pump system 142. This is arranged on a base 142a which will be welded or glued to the band 3100 of the strand 31 of the bracelet at the opening 3103. Thus, the user can act on the pump system 142 to inflate or deflate the bracelet strand.

However, the latter is used to carry the first material M1 that is to say the material capable of reflecting different wavelengths according to the stress applied to it. This first material M1 is in the form of a film more or less thick deposited on at least one of the two bands 3100 forming the strap strand 31 but it can also be provided that the first material M1 is an integral part of the material wherein the band or bands 3100 are made.

In a preferred configuration (not shown), for reasons of ease of process, said first material M1 comprises an opal film encapsulated in two transparent thermoplastic films (TPU type) and the material M1 constitutes at least one of the strips 3100 of the strand. In this way the manufacture of the pouch and its plastic pump system can be achieved easily by some heat sealing operations. Therefore, when the user is acting on the pump system 142, he can then increase or decrease the air pressure in the strap strand 31. If the pressure increases, the stress exerted by this increase in pressure is transmitted to the bands forming the strap strand 31 to cause a deformation of one and / or the other of the bands 3100. This deformation is transmitted to the first material M1 which thus sees its structure to be modified causing the reflection of a different wavelength. By acting on the exhaust valve 144 of the pump system 142, the air is discharged from the strand 31 of the bracelet which decreases the pressure inside thereof. This causes a decrease in the stress exerted on the 3100 strips which then resume their original shape. The first material M1 then resumes its initial structure and thus reflects its original wavelength.

Of course, it may be provided that the strips 3100 constituting the strap strand 31 are made of different materials. it advantageously makes it possible to have a material having more advantageous deformation characteristics for the strip carrying the first material M1. This causes the said band 3100 to become more easily deformable, resulting in better reactivity to pumping.

In a second visible alternative embodiment, the covering element 10 and the pocket 141 are dissociated. In a non-limiting example, the covering element 10 is a strand 31 of a bracelet. Such a strand, as described above, comprises two strips 3100 made integral and forming a hollow space 3102 between them.

Advantageously according to this alternative, the hollow space 3102 between the two strips 3100 is used as a housing. This housing is used to house a pocket 141 which can be inflated and deflated and provided with an opening 3103 for housing the pump system 142 as previously described. The principle is therefore that the activation of the pump 145 makes it possible to inflate or deflate the bag 141 causing its deformation and that of the bands 3100 forming the bracelet strand.

According to a first solution visible to the figure 11 one and / or the other band 3100 forming the bracelet strand carries the first material M1 as described for the first alternative embodiment. Thus, the inflation or deflation of the pocket 141 causes the application or not of a constraint on the wristband strand that is deformed or not.

According to a second solution visible to the figure 12 , it is expected that the pocket 141 is the element that carries the first material M1. This first material M1 is in the form of a film deposited on the pocket but it can also be provided that the first material M1 is an integral part of the material in which the pocket 141 is made. Cleverly, at least one of the bands 3100 of the bracelet strand 31 includes openings 3103. These openings 3103 allow the user to see the pocket 141 reflecting a certain wavelength through the band or bands 3100 forming the strand 31 of bracelet. By moreover, when the pocket 141 inflates under the action of the pump 145, the pocket 141 can be inserted partially into the openings 3103 and thus locally deformed. This local deformation thus causes a local stress on the first material M1 and thus a modification of the wavelength that it can reflect.

In a third alternative embodiment, visible at the figure 13 , the dressing element 1, here a bracelet strand 31, consists of a hollow 400 and a flexible film 410 made of the material M1 or carrying the material M1. The recess / film assembly constitutes the pocket 141. Similarly to the first alternative embodiment, a pump system 142 can then be arranged at the pocket 141 so as to inflate or deflate the pocket 141 and thus to apply a geometric stress on the material M1 and thus to change its color.

In a preferred version of this alternative for reasons of ease of process, the recess 400, the pump system 142 and the flexible film 410 sealing the pocket are made of thermoplastic. More preferably the recess 410 is incorporated in a strand 31 of the bracelet obtained by injection. The material M1 consists of an opal polymer film encapsulated between two sheets of thermoplastics. In this way, the covering element 1 can be obtained by simple assembly operations (ultrasound, heat sealing, or other).

In an example of realization visible to Figures 14 and 15 , the covering element 1 is a watch face 41, the portable object being a watch comprising a watch movement 25. In this case, it is intended to have a pocket 141 located under the dial 41, this pocket 141 can be made from two half-pockets heat-welded. This possibility of using two half-pockets makes it possible to have a pocket 141 made of different materials, such as having half-pockets with different stiffnesses so as to have a half-pocket acting as a support and a half-pocket. so-called active which will deform easily. This pocket 141 can then be arranged in the housing formed by the dial 41, the middle part 20 and the platinum of the watch movement.

This pocket 141 is then supplied with air via a pumping system 142 placed outside, at the level of the watch box 2 so as to be manipulated by the watch wearer. An ultrasonic bonding or a seal makes it possible to assemble this pumping system to the watch case in a sealed manner. The pumping system is connected to the pocket via a channel 146. This channel 146 is an integral part of the pocket 141 and is created by the addition of circular welds to reduce the thickness of the inflated area.

The dial 41 has openings 41a so that the pocket 141 is visible to the wearer of the portable object. The portion of the pocket visible by the wearer is the part that supports the first material M1. Thus, when the wearer acts on the pumping system, the bag inflates or deflates and the material M1 undergoes a stress that makes it change the wavelength of the light it reflects.

In a preferred version of the invention, the pocket carrying the material M1 is located in a window or a perforated dial to leave the pocket visible. When the pump is activated, the pocket carrying the material M1 inflates, the opal pattern changes color and appears in relief relative to the rest of the dial.

For all the embodiments of the invention, it is possible to modify the basic color and the color variation, by modifying the very structure of the opal material constituting M1 during its manufacture. Indeed, as described in the literature, the refractive indices, the size and the spacing of the components of the opal material, allow to control its original color and its colors after mechanical stress.

It will be understood that the embodiments described above are not limited to a bracelet or dial but can also be applied to a watch case, a caseband, a bezel, a crown, a pusher, a clasp or a buckle, or an ice cream.

It will be understood that various modifications and / or improvements and / or combinations obvious to those skilled in the art can be made to the various embodiments of the invention set out above without departing from the scope of the invention defined by the appended claims.

It will be conceivable that, in the first embodiment, the cladding element is made of a material that absorbs water. Such a configuration allows the dressing element to swell with moisture and thus causes the appearance of a stress on the first material.

Claims (22)

Cladding element (1) for a portable object comprising a support (12) on which is arranged a first material (M1), said first material being chosen able to reflect different visible wavelengths depending on the applied stress, said cladding element further comprising a device (14) for modifying the stress applied to said first material. Cladding element according to claim 1, characterized in that the support (12) and the device (14) for modifying the stress applied to said first material are one and the same piece. Cladding element according to claim 2, characterized in that the support (12) is a bistable metal strip (32) coated with said first material. Cladding element according to claim 1, characterized in that the device (14) for modifying the stress applied to said first material uses a second material (M2) able to see its varied volume as a function of a physical quantity, said second material being associated with a flexible element carrying the first material (M1). Cladding element according to claim 4, characterized in that the support (12) comprises at least one recess (40) closed by a film (42 ') provided with the first material (M1) and forming a housing, said housing accommodating a housing capsule (43 ') composed of two integral half-shells (44') filled with said second material (M2). Cladding element according to claim 4, characterized in that the support (12) comprises at least one recess (40) closed by a film (42) provided with the first material and forming a housing in which a capsule-piston system ( 43) and the material (M2) are placed, said capsule-piston system (43) consists of a half-shell (44) and a piston (45) so that the variation of the volume of the second material (M2) causes a displacement of the piston. Cladding element according to claim 5, characterized in that each capsule (43) is filled with said second material, which may be different from one capsule to another. Cladding element according to claim 6, characterized in that each recess (40) is filled with said second material (M2), which may be different from one housing to another. Cladding element according to claim 4, characterized in that the support (12) is formed by at least two integral parts (310) fixed together by their periphery so as to leave a space (312) empty between these two parts, at least one of the two parts being flexible and carrying said first material, said space forming the recess (40) containing the second material. Cladding element according to claim 9, characterized in that the support formed by the at least two parts further comprises at least one structure (313) extending between the two parts in order to define at least two zones (315), each zone may contain a pocket. Cladding element according to claim 10, characterized in that each zone (315) contains a second specific material. Cladding element according to claim 1, characterized in that the device (14) for modifying the stress applied to said first material comprises a pocket (141) of plastic material connected to a pump system (142) for inflation / deflating the ladle, said pump system comprising a hollow bell (143a) provided with a hole (143b) for filling the air of the bell and a check valve (145) having a pair of sheets (145a) of plastic material each welded, has a wall of the pump, said sheets being bent substantially U-shaped and arranged relative to each other to allow air to pass only in the direction of the pocket, said device being associated with a flexible member carrying the first material (M1). Cladding element according to claim 12, characterized in that the support (12) is formed by at least two fixed parts (3100) together by their periphery so as to leave a gap (3102) between them, said space allowing housing therein the pocket (141), one of the portions forming the strand being provided with an opening for the pump system (142) to be inserted therein and to be accessible. Cladding element according to claim 13, characterized in that at least one of the two parts (3100) is flexible and carries the first material (M1). Cladding element according to Claim 13, characterized in that the at least one of the two parts (3100) is perforated, the first material being supported by the pocket acting as a flexible element and visible through the perforation. Cladding element according to claim 12, characterized in that the support (12) is formed by at least two parts (3100) integral and fixed together by their periphery so as to leave a space (3102) empty between these two parts, at least one of the two parts being flexible and carrying the first material, said space forming the pocket (141) of the pump system, one of the parts forming the strand being provided with an opening so that the pump system therein be arranged. Cladding element according to one of the preceding claims, characterized in that said first material (M1) is in the form of a film deposited on said support (12, 32). Cladding element according to one of Claims 4 to 11, characterized in that the flexible element (42, 42 ', 310, 3100) consists at least in part of the first material (M1). Cladding element according to one of Claims 13 to 16, characterized in that the flexible part (42, 42 ', 310, 3100) consists at least in part of the first material (M1). Portable object comprising a housing closed by a bottom and a cover, characterized in that said portable object comprises at least one covering element (1) according to one of the preceding claims. Portable object according to claim 20, characterized in that said portable object is a timepiece comprising a housing (2) formed by a middle part (20) closed by a bottom (21) and an ice (22), and a bracelet (3) fixed to the middle part via two pairs of horns (24), said bracelet being provided with at least one strap strand (31), and in that the covering element is chosen to be arranged in the list including the middle part, the bottom, the bracelet. Portable object according to claim 21, characterized in that said timepiece further comprising a clockwork providing a time information to display means comprising a dial (41), said dial being part of the list in which the dressing element is chosen.

Images