CH711959A2 - Zirconia cladding element with selectively conductive zones for electronic applications. - Google Patents

Abstract

The present invention relates to a casing element for portable object (1) made of a first material, the first material being an insulating ceramic material. The surface of said cladding element is at least partially treated so as to have at least one transformation provided with an electrical conductivity.

Description

Description: [0001] The present invention relates to a cladding element and its manufacturing method made of zirconia type ceramic whose conductivity is selectively modified.

PRIOR ART

It is known portable objects such as watches or bracelets that are partly made of ceramic. A known ceramic is zirconia ZrO 2.

Moreover, the current trend of portable objects is to go to more and more electronic features and connectivity.

This increase in the technology embedded in the watches is in the form of the integration of tactile control means offering a more intuitive and fun use or is in the form of the integration of wireless communication functions, the watch can then communicate with another device such as a smartphone.

However, this increase in electronic functionality is problematic because it involves an increase in components and impose additional constraints on the trim parts. For communication, it is necessary to have an antenna involving an antenna support and a connector to connect the antenna to the main electronic module. The area where the antenna is located must be free of electrically conductive parts in order to have the best transmission properties possible.

Similarly, in the case of tactile keys, it is necessary to have electrodes and therefore to have means for supporting these electrodes and means for connecting these electrodes to the main electronic module. These electrodes must also be electrically isolated from disruptive conductive elements.

It is therefore found that the integration of new technologies tends to add components and constraints, which implies a miniaturization and adaptation thereof is an increase in costs or an increase in the size of the housing. the watch or an aesthetic change.

[0008] There is therefore a need to find a solution to this increase in electronic functionality in a watch.

SUMMARY OF THE INVENTION

The present invention aims to overcome the disadvantages of the prior art by providing a ceramic cladding element and its manufacturing method that allow the selective production of conductive areas to allow the integration of features.

For this purpose, the invention relates to a cladding element for a portable object made of a first material, the first material being an insulating ceramic material, characterized in that the surface of said cladding element is at least partially treated so as to have at least one transformation provided with a non-zero electrical conductivity.

This invention makes it possible to have a cladding element which has insulating zones and zones having an electrical conductivity such that it is possible to use them for applications of the type conducting tracks, antennas, electronic circuits or electrodes for touch keys.

In a first embodiment, the first material is zirconia.

In a second embodiment, the surface is selectively processed to be converted into zirconium carbide whose conductivity is non-zero.

In a third embodiment, the surface is selectively processed to be converted into zirconium nitride whose conductivity is non-zero.

In a fourth embodiment, the surface comprises at least one recess, the surface being treated to be converted into carbide or nitride, and then polished to locate this transformation at said recess.

In a fifth embodiment, the surface comprises at least one projecting portion, the surface being treated to be converted into carbide or nitride, and then polished to exclude this transformation of said projecting portion.

In a sixth embodiment, the surface is converted into carbide or nitride homogeneously, then machined locally to locate the transformation on the non-machined parts.

The present invention also relates to a portable object comprising the covering element according to one of the preceding claims.

In a first embodiment, said portable object is a timepiece comprising a case formed by a middle part, provided with a bezel, closed by a bottom and an ice, said portable object further comprising means for command, and a bracelet with its clasp attached to the middle via two pairs of horns, and in that the dressing element is chosen to be arranged in the list comprising the middle part, the bezel, the control means, the bottom , the bracelet or the clasp.

In another embodiment, said portable object further comprises an electronic module adapted to use said treated surface so as to have at least one transformation provided with a non-zero electrical conductivity to operate at least one function.

In another embodiment, the treated surface so as to have at least one transformation provided with a non-zero electrical conductivity will be an antenna for operating a communication function.

In another embodiment, the treated surface so as to have at least one transformation provided with a non-zero electrical conductivity will be an electrode for operating a control function.

In another embodiment, the treated surface so as to have at least one transformation provided with a non-zero electrical conductivity will be a wall used in a shielding function to isolate a module or electronic component of the disturbances of another module or electronic component.

In another embodiment, the treated surface so as to have at least one transformation provided with a non-zero electrical conductivity will be at least one conductive tracks for electrically connecting a module or electronic component to at least one other module or electronic component.

The present invention further relates to a method of treating a covering element for a portable object made of a first material, the first material being an insulating ceramic material, said method comprising the following steps: • To provide the cladding element and placing it in a hermetically sealed enclosure containing an atomically charged atmosphere of a chemical element; • Heating locally, through a first source of focused heat such as a laser, the surface of the cladding element so that the atoms of the atmosphere of the enclosure combine locally with the surface from the first material to where said surface is heated.

In a first embodiment, the atmosphere is created by dissociating a gas via the same heat source locally heating the surface of the cladding element.

In a second embodiment, the atmosphere is created by dissociation of a gas via a second heat source independent of that which locally heats the surface of the cladding element.

In a third embodiment, the atmosphere is created by dissociation of a gas via a second source of heat independent of the first source which locally heats the surface of the covering element, the element of coating being heated homogeneously via a third heat source at a lower temperature than that allowing the combination of the atoms of the atmosphere with the first material, the first heat source for locally raising the temperature of the surface of the cladding element to allow the combination of the atoms of the atmosphere with the first material.

In a first variant, said method comprises the following steps: • Bring the dressing element; • Deposit locally on the surface of said cladding element a metal layer which will act as a mask to limit the carburetion or nitriding zirconia areas of the surface of the cladding element not protected by the metal deposition; • Place the covering element in a hermetically sealed enclosure containing an atomically charged atmosphere of a chemical element and heat the surface of the cladding element so that the atoms of the compound of the atmosphere of the enclosure become combine with the surface of the first material not covered with the metal deposit; • Selectively and chemically attack the surface of said cladding element in order to remove the metal deposit in order to confine the conductive zones to the zones not covered by the metal deposit during the carburizing / nitriding step.

In a first embodiment, the selective metal deposition is performed by depositing through a mask previously placed on the cladding element.

In a second embodiment, the selective metal deposition is performed by deposition followed by a laser structuring step of the surface of said cladding element.

In a third embodiment, the selective metal deposition is performed by deposition followed by a photolithography step of the surface of said dressing element.

In a fourth embodiment, the step of depositing a selective metal layer consists of depositing a savings layer on the entire surface of said dressing element and then selectively etching this savings layer according to a desired shape and then depositing the metal tick on the entire surface of said cladding element, the remaining savings layer being subsequently etched away.

In a second variant, said method comprises the following steps: • Bring the dressing element; • Treat said cladding element by placing it in a hermetically sealed enclosure containing an atomically charged atmosphere of a chemical element and heating its surface so that the atoms of the enclosure atmosphere combine with the surface of the cladding. first material; characterized in that said method further comprises, before or after the step of treating said dressing element, a step of structuring the dressing element allowing the creation of relief on its surface.

In a first embodiment, when the structuring step of the dressing element is performed after the step of treating the surface of said dressing element, the structuring removes the surface layer on the zones. structured and locates it on unstructured areas.

In a second embodiment, the method further comprises, when the structuring step of the covering element is carried out prior to the step of treating the surface of said dressing element, a step of polishing to remove the surface layer on the upper portion of the raised surface of the trim element and thereby locate the conductive areas to the hollows not touched by polishing.

BRIEF DESCRIPTION OF THE FIGURES

The objects, advantages and features of the invention will appear more clearly in the following detailed description of at least one embodiment of the invention given solely by way of non-limiting example and illustrated by the accompanying drawings in which: :

Figs. 1 and 2 schematically represent the portable object according to the invention;

Figs. 3 to 5 schematically represent a first embodiment of the method according to the invention;

Figs. 6 to 20 schematically represent a second embodiment of the method according to the invention;

Figs. 21 and 22 show schematically a third embodiment of the method according to the invention;

DETAILED DESCRIPTION

In FIGS. 1 and 2, a portable object 1 according to the invention is described. An example of a portable object according to the invention is a timepiece. Such a timepiece comprises a housing 2 formed by a middle part 21 closed by a bottom 22 and an ice 3. This housing 2 encloses an electronic module that can be an electronic or electromechanical watch movement. This electronic module can be associated with another element such as a mechanical movement. This portable object may also comprise a bracelet 4 comprising two strands 4 'or a plurality of links. A dressing element according to the invention is therefore included in the list comprising the middle part, the bezel, the bottom, the bracelet, the clasp, the folding clasp or the buckle - pin necessary for closing the bracelet. Of course, the watch may also include a bezel 23, rotating or not, integrated or not to the middle part, and control means such as a crown head 24 or push buttons 24 '. The middle part 21 may be provided with an integrated or reported bezel.

The dressing element according to the invention is made of a first material. This material is chosen to be of the ceramic type. The ceramic used here is zirconium oxide ZrO 2 also called zirconia.

Advantageously according to the invention, this ceramic cladding element 10 is surface-treated. This surface treatment is operated so as to be selective, that is to say that the covering element 10 is not necessarily treated on its entire surface. This surface treatment is used to obtain a change of electrical conductivity on specific areas.

In a first embodiment visible in FIGS. 3 to 5, the treatment according to the present invention consists in a selective carburization / nitriding of the covering element 10 by a focused heat source, such as a laser.

As a reminder, a carburation / nitriding is to activate the carburizing / nitriding part by heating it in an atmosphere charged with carbon atoms or nitrogen.

The first step is therefore to provide the dressing element 10 which will be treated and place it in an enclosure E. This enclosure E is hermetically sealed and contains an atmosphere A charged with carbon atoms C or d nitrogen N according to whether carburetion or nitriding is practiced. This atmosphere charged with carbon atoms C or nitrogen N can be created by dissociation of compounds such as methane CH4, dinitrogen N2 or ammonia NH3. This dissociation is operated by heating the basic compounds to break the molecular bonds and obtain atomic atmospheres.

The second step is to selectively carburize or nitride the trim member 10 by activating the surface of the piece by heating in selected areas 10 '. In order to be able to selectively heat said surface in the selected areas 10 ', a focused heat source S, e.g. a laser providing a laser beam L, is used. This laser beam is preferentially pulsed. The surface of the covering element 10 is then heated locally in zones 10 'at a temperature of between 700 and 1100 ° C. for a period of 30 to 180 minutes. Under the effect of this temperature, the carbon or nitrogen atoms of the atmosphere A of the enclosure E combine with the zirconia surface in the zones 10 'of the covering element 10. a transformation of the surface of the zones 10 'of the covering element 10 to a small thickness, of the order of 10 to 500 nm, of zirconium carbide or zirconium nitride having a metallic appearance of platinum color or close to yellow gold respectively, and a non-zero conductivity. It is therefore a superficial modification of the zirconia structure into a new crystallographic structure corresponding to that of zirconium carbide / zirconium nitride and not of an added coating that can be torn off or separated from the zirconium carbide. surface of the article, especially when it is subject to significant wear conditions. More particularly, the surface layer which has the structure of zirconium carbide or zirconium nitride extends from the surface to a depth of between 10 and 500 nm.

However, zirconium carbide and zirconium nitride have a non-zero electrical conductivity unlike zirconia which is considered an insulating material. As a result, the areas that are carburized or nitrided have non-zero electrical conductivity. As the rest of the cladding element is not transformed, we end up with conductive zones surrounded by insulating zones.

To operate the different steps, it can be provided several modes of execution.

In a first embodiment, the dissociation of the gases to obtain an atmosphere charged with carbon atoms G or nitrogen N and the local activation of the surface of said dressing element use the same laser.

In a second embodiment, the dissociation of the gases to obtain an atmosphere charged with carbon atoms C or nitrogen N is operated by a first source of heat while the local activation of the surface of said element d dressing 10 uses the laser.

In a third embodiment, the dissociation of the gases to obtain an atmosphere charged with carbon atoms C or nitrogen N is operated by a first source of heat, the dressing element 10 is heated via a second source of heat while the local activation of the surface of the dressing element uses the laser. This third embodiment makes it possible to preheat the cladding element 10 in a homogeneous manner and to have a smaller temperature difference in the area of the surface of the cladding element 10 treated by the focused heat source. .

An advantage of this first embodiment is that it allows a selective activation of the surface of the covering element 10 easily. Indeed, a laser beam has the advantage of having an adjustable beam diameter. .

In a second embodiment visible in FIGS. 6 to 20, the principle uses a selective metallization as a mask to obtain a carburetion or selective nitriding of the surface of the covering element 10.

The first step is therefore to provide the cladding element 10 and affix a metallization 11 on its surface. This metallization is selective, that is to say that it is performed on the zone or zones that it is desired to carburize or nitride. This metal deposit is made for example in a material included in the list including chromium, tantalum, molybdenum, tungsten, niobium, titanium, silicon and is made according to several embodiments.

In a first embodiment shown in FIGS. 7 and 8, the metallization is carried out by masking the surface of the covering element 10 via a mask 12 followed by a metal deposition via a PVD physical vapor deposition method. Thus, only zones Z not covered by the mask receive the metal deposit 11.

In a second embodiment shown in FIGS. 9 to 12, the metallization is carried out by depositing a savings layer 13 such as a capton layer or a layer of ink or lacquer or resin on the surface of the covering element. This layer 13 is then selectively etched according to the desired aesthetic and reveals openings 13 '. The whole is then covered with a metal layer 11 by PVD deposition, the layer being deposited on both the savings layer 13 and in the recesses made in said savings. Finally, the savings layer 13 is etched away leaving the metal layer 11 only on the Z zones corresponding to the locations of the recesses 13 'of the savings removed.

In a third embodiment shown in FIGS. 13 to 15, the selective metal deposition consists of depositing on metal 11 over the entire surface of the covering element 10 and then using a focused heat source S such a laser to structure the deposited metal layer 11. This structuring consists of stripping the surface of the covering element 10 to remove the metal layer 11 at undesired locations and leaving the metal layer 11 on the desired zones Z.

In a fourth embodiment shown in FIGS. 16 to 18, the selective metal deposition consists of depositing the metal on the entire surface of the covering element 10. Following this, a photolithography step is used with a mask 12 to locally modify the deposited metal layer 11 . This local modification is followed by a chemical attack step to remove the metal layer 11 at unwanted locations and leave it on the desired zones Z.

Once this metal deposition is achieved, the next step is to carburize or nitride the trim element 10 with the metal layer 11 on the Z zones of its surface. For this purpose, the covering element 10 is placed in an enclosure E which contains an atmosphere A loaded with carbon atoms C or nitrogen N, as shown in FIG. 19. The whole is then heated using a plasma technique as described in patent EP 0 850 900. However, the metal deposit 11 serves here shield preventing carburation / nitriding areas covered by this metal deposit 11 and allowing the transformation to the zones 10 'uncovered as visible in FIG. 20.

In a next step, the metal deposit 11 is chemically dissolved to reveal the zirconia in its original color. Thus, a covering element having a bare area and a carburized / nitrided and therefore conductive zone is obtained.

In a third embodiment, the selective transformation of the surface of the cladding element into a conductive zone uses the principle of carburation / nitriding and structuring.

In a first embodiment shown in FIG. 21, the first step is to provide the cladding element 10 zirconia. This first step also consists in structuring this covering element 10. This structuring can be operated in two different ways: During the manufacture of the covering element 10 or later than this manufacturing.

In the case where the structuring is carried out during the manufacture of the cladding element, it will be understood that this manufacture consists of mixing together powders to then put them in a mold and the fritter, that is to say the subject to a temperature and pressure such that a transformation takes place. Thus, the mold in which the powders are placed can have a shape including the desired reliefs, structures.

In the case where the structuring is carried out after the manufacture of the cladding element, a mechanical or laser machining is possible.

In a second step, the cladding element is carburized or nitride. For this, the structured dressing element 10 is placed in an enclosure E in which there is an atmosphere A charged with carbon atoms or nitrogen. The whole is then heated via a plasma for a predetermined period of time in order to transform the surface of the cladding element 10 into conductive zirconium carbide or nitride respectively. This carburation / nitriding is therefore performed on the entire surface of the trim element.

In a third step, the dressing element undergoes a polishing step. This polishing step consists in removing the surface layer of the covering element 10. However, the covering element 10 is provided with structural elements 17 in the form of recesses 17b or projections 17a, these recesses 17b. or protruding parts 17a are also carburized / nitrided. Therefore, the polishing does not affect the entire surface of the covering element 10. Indeed, in the case where the structures 17 are recesses, the polishing operation leaves the carburization / nitriding is ie the conductive parts, in the recesses. In the case where the structures 17 are protruding parts, the polishing operation removes the carburization / nitriding at these protrusions.

Thus, we obtain a relief whose recesses are selectively conductive.

In a second embodiment shown in FIG. 22, the first step is to provide the zirconia cladding element.

In a second step, said dressing element is carburized / nitrided. For this, the structured dressing element 10 is placed in an enclosure in which there is an atmosphere charged with carbon atoms or nitrogen. The whole is then heated via a plasma for a predetermined period of time in order to transform the surface of the conductive zirconium carbide or nitride cladding element respectively. This carburation / nitriding is therefore performed on the entire surface of the trim element.

In a third step, the dressing element 10 undergoes a structuring step. This step involves removing material from the trim element. For this, a mechanical or laser machining is used. The removal of material can be carried out so as to remove locally only the surface layer of 10 to 500 nm which is converted into carbide or nitride. However, the removal of material can be operated so as to accentuate the relief at the conductive areas.

This transformation of the surface dressing element to present areas having an electrical conductivity makes it possible to produce conductive tracks for electrically connecting a module or electronic component to at least one other module or electronic component, integrated antennas, as well as electrodes for keys or touch controls. These zones having a non-zero electrical conductivity will be used by the electronic module of the portable object. These zones having a non-zero electrical conductivity also make it possible to operate a function

Claims (23)

shielding that is to say to isolate a module or electronic component disturbances of another module or electronic component. 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 described above without departing from the scope of the invention defined by the appended claims. Thus, it will be understood that the trim element can be treated at different locations on its surface. claims 1. A covering element (10) for a portable object made of a first material, the first material being an insulating ceramic material, characterized in that the surface of said covering element is at least partially treated so as to present at least one transformation provided with non-zero electrical conductivity. 2. Cladding element according to claim 2, characterized in that the first material is zirconia. 3. cladding element according to claims 1 or 2, characterized in that the surface is selectively treated to be converted into carbide. 4. Cladding element according to claims 1 or 2, characterized in that the surface is selectively treated to be converted into nitride. 5. cladding element according to one of claims 1 to 4, characterized in that the surface comprises at least one recess (17b), the surface being treated to be transformed into carbide or nitride and polished to locate this transformation at the level of said hollow. 6. cladding element according to one of claims 1 to 4, characterized in that the surface comprises at least one projecting portion (17a), the surface being treated to be converted into carbide or nitride and polished to exclude this transformation of said projecting portion. Portable object comprising the covering element according to one of the preceding claims. 8. Portable object according to claim 7, characterized in that said portable object is a timepiece comprising a housing (2) formed by a middle part (21), provided with a bezel, closed by a bottom (22) and an ice cream (3), said portable object further comprising control means (24, 24 '), and a bracelet (4) attached to the middle via two pairs of horns, and in that the dressing element is chosen to be arranged in the list comprising the caseband, the bezel, the control means, the bottom, the bracelet or the clasp. 9. Portable object according to claim 8, characterized in that said portable object further comprises an electronic module (5) adapted to use said treated surface so as to have at least one transformation provided with a non-zero electrical conductivity to operate at less a function. 10. Portable object according to claim 9, characterized in that the treated surface so as to have at least one transformation provided with a non-zero electrical conductivity will be an antenna to operate a communication function. 11. Portable object according to claims 9 or 10, characterized in that the treated surface so as to have at least one transformation provided with a non-zero electrical conductivity will be an electrode for operating a control function. 12. Portable object according to one of claims 9 to 11, characterized in that the treated surface so as to have at least one transformation provided with a non-zero electrical conductivity will be a wall used in a shielding function to isolate a module or electronic component of the disturbances of another module or electronic component. 13. Portable object according to one of claims 9 to 12, characterized in that the surface treated so as to have at least one transformation provided with a non-zero electrical conductivity will be at least one conductive tracks for electrically connecting a module or electronic component to at least one other module or electronic component. 14. A process for treating a portable object covering element (10) made of a first material, the first material being an insulating ceramic material, said method comprising the following steps: • Providing the covering element and placing it in an enclosure (E) hermetically closed and containing an atomically charged atmosphere of a chemical element; • Heating locally, via a first heat source (S) focused, the surface of the element of dressing so that the atoms of the atmosphere of the enclosure are combined with the surface of the first material . 15. The treatment method as claimed in claim 14, characterized in that the atmosphere is created by dissociating a gas via a second heat source. 16. The treatment method according to claim 14, characterized in that the atmosphere is created by dissociating a gas via a second heat source, the dressing element being heated to a temperature lower than the temperature of activation of the combination of the atoms of the atmosphere with the surface of the first material via a third source of heat. 17. A method of treating a covering element (10) for a portable object made of a first material, the first material being an insulating ceramic material, said method comprising the following steps: • To equip the dressing element ; • Deposit locally on the surface of said cladding element a metal layer (11); • Place the covering element in a sealed enclosure containing an atomically charged atmosphere of a chemical element and heat the surface of the cladding element so that the atoms of the enclosure atmosphere are combined with the surface of the first material not covered with the metal deposit. • Selectively and chemically attack the surface of said dressing element in order to remove the metal deposit. 18. Processing method according to claim 17, characterized in that the selective metal deposition is performed by depositing through a mask (12) previously placed on the cladding element. 19. Processing method according to claim 17, characterized in that the selective metal deposition is carried out by deposition followed by a laser structuring step of the surface of said cladding element. 20. The method of treatment according to claim 17, characterized in that the selective metal deposition is carried out by deposition followed by a photolithography step of the surface of said cladding element. 21. Treatment method according to claim 17, characterized in that the step of depositing a metal layer (11) consists in depositing a savings layer (13) on the entire surface of said dressing element and then in selectively etching this savings layer in a desired shape and then depositing the metal layer (11) on the entire surface of said dressing element, the remaining savings layer being subsequently removed by etching, thus leaving the metal layer where the savings layer was previously engraved. 22. A process for treating a portable object covering element (10) made of a first material, the first material being an insulating ceramic material, said method comprising the following steps: • Providing the covering element , • Treat said cladding element by placing it in a hermetically sealed enclosure containing an atomically charged atmosphere of a chemical element and heating its surface so that the atoms of the enclosure atmosphere combine with the surface of the cladding. first material; characterized in that said method further comprises, prior to or after the step of treating said dressing element, a step of structuring the dressing element allowing the creation of relief (17) on its surface and of locate the carburised / nitrided conductive layer in the projections or recesses of the relief. 23. Treatment method according to claim 22, characterized in that it further comprises, when the step of structuring the dressing element is carried out prior to the step of treating said dressing element, a polishing step for removing the carburised / nitrided surface layer on the protruding portions of the raised surface of the trim member.