EP2503415B1 - Decorated enamelled part - Google Patents

Description

Field of the invention

The invention relates to an enamelled piece for a timepiece or jewelery and more specifically, such a piece having decorations.

Background of the invention

It is known from the document EP 1 640 822 to make high-end enamelled dials from a ceramic substrate coated with a layer of enamel to make them less artisanal. However, it becomes necessary to also form the indexes or graduations according to the same high-end appearance. Nowadays, for example, it is not possible to make sets with the same rendering as the main enameling of the dial or even to offer metal decors to render as high-end.

The document FR 2432942 describes an enamelled piece comprising two layers of enamel superimposed. The document EP 1538493 discloses a ceramic substrate dial coated with a single layer of enamel.

Summary of the invention

The object of the present invention is to overcome all or part of the drawbacks mentioned above by proposing enamelled parts, such as for a dial, whose metallized decor or not are rendered substantially equivalent to the main enameling of the piece.

For this purpose, the invention relates to an enameled part for a dial comprising a ceramic substrate coated with a first enamel layer, at least one other enamel layer partially covering the first enamel layer, characterized in that said at least one other layer of enamel is at least partially covered with a metal layer.

It is therefore understood that, in a preferred manner according to the invention, it is possible to obtain enamelled pieces for a dial, that is to say the dial itself or a portion attached to the dial or a part similar to a dial, whose decorations, metallized or partially metallized, offer an overall homogeneous performance compared to the main enameling of the piece, that is to say, upscale.

• ladite au moins une autre couche est totalement recouverte d'une couche métallique ;
• ladite au moins une autre couche est de couleur différente et/ou sensiblement identique à la première couche d'émail ;
• ladite au moins une autre couche comporte une épaisseur variable afin d'offrir un dégradé de couleur ;
• ledit décor forme au moins un symbole alphanumérique et/ou un dessin.

According to other advantageous features of the invention:

• said at least one other layer is completely covered with a metal layer;
• said at least one other layer is of different color and / or substantially identical to the first enamel layer;
• said at least one other layer has a variable thickness to provide a color gradient;
• said decoration forms at least one alphanumeric symbol and / or a drawing.

1. a) former un substrat à base de céramique dont la partie visible est revêtue d'une première couche d'émail ;
2. b) former sélectivement une autre couche d'émail par-dessus de la première couche d'émail afin de former un décor sur ladite surface visible.

caractérisé en ce qu'il comporte l'étape suivante :

1. e') recouvrir au moins partiellement ladite une autre couche d'émail d'une couche métallique afin que ledit décor présente une réflexion qui est homogène quelle que soit l'incidence lumineuse.

In addition, the invention relates to a method of decorating an enameled part for a dial comprising the following step:

1. a) forming a ceramic-based substrate whose visible portion is coated with a first enamel layer;
2. b) selectively forming another enamel layer over the first enamel layer to form a pattern on said visible surface.

characterized in that it comprises the following step:

1. e ') at least partially covering said other layer of enamel with a metal layer so that said decoration has a reflection which is homogeneous regardless of the light incidence.

• ladite au moins une autre couche comporte une épaisseur variable afin d'offrir un dégradé de couleur ;
• l'étape b) comporte les phases c) : imprimer sélectivement, sur ladite première couche d'émail, ledit décor à l'aide d'une solution précurseur de ladite une autre couche d'émail et d) : chauffer la pièce afin transformer la solution précurseur en émail ;
• la température de transformation de ladite une autre couche d'émail est au moins 100°C moins élevée que celle de la première couche d'émail afin de ne pas détériorer cette dernière lors de chaque étape b) ;
• la phase c) est réalisée par tampographie ou sérigraphie ;
• ladite une autre couche est de couleur différente et/ou sensiblement identique à la première couche d'émail .

According to other advantageous features of the invention:

• said at least one other layer has a variable thickness to provide a color gradient;
• step b) comprises phases c): selectively printing, on said first enamel layer, said decoration using a solution precursor of said another enamel layer and d): heating the room to transform the precursor enamel solution;
• the transformation temperature of the said other enamel layer is at least 100 ° C lower than that of the first enamel layer so as not to damage it during each step b);
• phase c) is performed by pad printing or screen printing;
• said another layer is of different color and / or substantially identical to the first enamel layer.

Brief description of the drawings

• la figure 1 est une représentation d'une première variante d'application selon l'invention ;
• la figure 2 est une représentation d'une deuxième variante d'application selon l'invention ;
• la figure 3 est une représentation d'une troisième variante d'application selon l'invention ;
• la figure 4 est une représentation d'une quatrième variante d'application selon l'invention ;
• les figures 5 à 7 sont des représentations d'étapes principales d'un procédé de décoration selon l'invention ;
• la figure 8 est une représentation d'une étape finale du procédé de décoration selon l'invention.

Other particularities and advantages will emerge clearly from the description which is given hereinafter, by way of indication and in no way limiting, with reference to the appended drawings, in which:

• the figure 1 is a representation of a first variant of application according to the invention;
• the figure 2 is a representation of a second variant of application according to the invention;
• the figure 3 is a representation of a third variant of application according to the invention;
• the figure 4 is a representation of a fourth variant of application according to the invention;
• the Figures 5 to 7 are representations of main stages of a decoration process according to the invention;
• the figure 8 is a representation of a final step of the decoration process according to the invention.

Detailed Description of the Preferred Embodiments

The invention has been developed for an enamelled piece of a timepiece such as a dial or a crown. Of course, the present invention can not be limited to the field of watchmaking. Other applications are also conceivable, such as, for example, jewelery or jewelery for cufflinks, earrings or pendants.

So, at the figure 1 , we can see an example of a timepiece 1 whose dial 3 has most of the pitfalls that can be encountered. The dial 3 thus comprises a main surface P constituting the widest visible face.

As visible at figure 1 , over the surface P, the dial 3 may comprise, reported (s), a time lapse 2 and / or a secondary display 4 formed (s) by at least one index and / or at least one alphanumeric symbol.

The dial 3 may also include a secondary display 5 whose visible surface is mounted in a plane above the surface P to form a raised area. Conversely, the dial 3 may also include a secondary display 6 whose visible surface is mounted in a plane below the surface P to form a recessed area. The dial 3 may also include a window 7, that is to say an opening of the dial 3 to show part of the movement 8 mounted under dial 3, like a moon phase 11 in the example of the figure 1 .

The invention advantageously relates to a decorated enamelled piece having a single plane P, that is to say comprising a single planar surface or not, or several planes. According to the invention, the enameled part comprises a ceramic substrate which is coated with a first layer of enamel to improve the appearance of said dial. Of course, when we speak of an enamel layer in the present text, it is necessary to understand a stack of coatings of the same enamel with a thickness of between 0.1 mm and 0.4 mm making it possible to give the color more or less sustained desired.

Advantageously according to the invention, the enameled part comprises at least one other enamel layer partially covering the first enamel layer in order to form a decoration with an improved appearance similar to that of the first enamel layer. The term at least one other enamel layer is understood as one or more layers. Each layer may cover the first layer of enamel and / or another layer of enamel as will be explained below.

Thus, advantageously according to the invention, each at least one other layer may be of different or substantially identical color to the first enamel layer. Indeed, it is sometimes desirable to include "secret" signatures, that is to say hardly identifiable at first glance. This is made possible by the application of a second enamel layer of the shape of the signature 9, as illustrated in FIG. figure 1 , a color substantially identical to that of the first enamel. The signature 9 will then be visible only by the shadow that it will project in grazing light incidence.

Each at least one other layer may also include a different color layer. Thus, a first possibility may consist in forming the entire decoration with a layer of a single second enamel cutting with the color of the first enamel. As an example, we obtain then a quality of rendering close to the first layer of enamel while contrasting the decor clearly with respect to the first layer of enamel as visible in the figure 1 for the hour turn 2.

Alternatively to this first possibility, parts of the decor may have a thicker layer of the second enamel to give the impression of a color gradient. Indeed, the parts of the decor having less thickness of the second enamel, let, through transparency, pass part of the color of the first enamel giving the impression of an intermediate color.

For example, Exhibit 21 of the figure 3 forms an enamel layer celestial card 25 over a first layer of white enamel 24. In order to present a variation of light blue to dark blue, an area 22 has a lower thickness of the second enamel 25 than the rest of the decor passing from zone 22 of the light blue towards the rest of the decor in dark blue from the same type of enamel layer 25.

A second possibility may be to form several layers of different colors to offer a more refined presentation called "degraded". The decor 2 'illustrates the figure 4 this second possibility by at least one layer of an enamel of intermediate color, which layer is then itself partially covered with said layer of second enamel cutting edge with the color of the first enamel. By way of example, it is thus possible, for a first white enamel 4 ', to successively form a gray enamel intermediate layer 6' for all the decoration 2 'and a final layer of enamel 8' black in the widest parts of the decoration 2 '.

According to the invention, said at least one other layer is, advantageously, totally or partially covered with a metal layer so that said decoration has a reflection that is homogeneous regardless of the light incidence.

Indeed, if a metal layer is formed directly on an enamelled piece, it does not reflect the light and therefore returns its color only by a single incidence which has the disadvantage of a high-end enamelled piece with dark metal parts except under a particular luminous incidence.

Advantageously, after a thickness setting made according to the invention, a metal layer is formed on top. Indeed, the setting thickness makes the decor substantially curved and, once coated with a layer of metal, returns a portion of its color regardless of the light incidence. We thus obtain a metal rendering as high-end as the first layer of enamel.

According to an alternative of this embodiment, the metal layer covers the entire second layer of enamel in order to present a totally metallic decoration such as a time lapse 2 of the figure 1 or the constellations 23 of the figure 3 . Of course, it is thus possible to form either fully coated surfaces such as the moon 13 of the figure 2 , only contours coated like the stars 15 of the figure 2 whose center is empty by making visible the first layer of enamel 12.

According to the invention, the metal layer partially covers the second layer of enamel in order to present a decoration comprising a metal part and an enamelled part other than the first layer of enamel such as the moon 17 of the figure 2 whose face is formed by perforations of the metal layer making visible the second layer of enamel 14. Of course, it is also possible to form contours coated as the stars 19 of the figure 2 whose center is perforated to reveal the second layer of enamel 16.

It is thus understood that, in a preferred manner according to the invention, it is possible to obtain enamelled pieces for a dial, that is to say the dial itself or a portion attached to the dial or a part similar to a dial, whose decorations, metallized or not, provide a uniform overall rendering compared to the main enameling of the piece, that is to say top of the line.

The manufacture of the enamelled piece according to the invention will be better understood in relation to the Figures 5 to 8 . The method according to the invention relates to the decoration of an enamelled piece for a dial, that is to say, suitable for a dial. According to a first step a) of a first embodiment, the method consists in forming a ceramic substrate 31 whose visible portion 32 is coated with a first enamel layer 33. As visible in FIGS. Figures 5 and 6 , the visible surface 32 is not necessarily flat and may also include upper (s) and / or lower (s) (not shown) as explained above.

According to the invention, the process is continued with one or more step (s) b) of selectively forming another enamel layer 35, 37, 39, 41, 43, 45 over the first layer of enamel 33 to form a decoration on said visible surface 32 as illustrated in FIG. figure 7 . Thus, the number of steps b) depends, as explained above, if one wishes to achieve a decor with a single layer of enamel with or without 43, different thicknesses such as for example the "secret" signature 9 of the figure 1 or the bottom 25 of the celestial map of the figure 3 , if it is desired to make several decorations with a single layer of enamel 39 with or without different thicknesses such as the hour tower 2 of the figure 2 , if it is desired to create a decoration with several different enamel layers 35, 41 with or without different thicknesses, such as the decoration 2 'of the figure 4 or if it is desired to make several decorations with several layers of enamel 37, 39, 41, 43, 45 different or not and with different thicknesses or not as the part 11 used to display moon phases.

Preferably according to the invention, each step b) comprises a first phase c) of selectively printing, on said first enamel layer 33, the decoration 35, 37, 39, 43, 45 or on another layer enamel 35, the decor 41 with a precursor solution of the future enamel layer, then a second phase d) of heating the workpiece to transform the precursor solution into enamel. According to the invention, the precursor solution is formed of particles, comprising enamel powder and pigments for the future coloration, which are suspended in a solvent such as oil.

In addition, the transformation temperature of the phase d) of each additional enamel layer 37, 39, 41, 43, 45 is preferably at least 100 ° C. lower than that of the first enamel layer 33 so as not to damage the first layer of enamel 33 existing during each step b). To achieve this, one can, for example, use so-called "small fire" enamels for decorations 35, 37, 39, 41, 43, 45 and a glaze called "big fire" for the first layer 33. As for example, the enamel "small fire" can for example react and vitrify around 600 ° C and enamel "big fire" around 1000 ° C. This difference in temperature much higher than 100 ° C is chosen so that, during the heating of the enamel "small fire", the structure of enamel "big fire" is not influenced or little.

It is therefore understood that, depending on the number of additional layers of enamels 37, 39, 41, 43, 45 to be added to the first layer 33, it is preferable to choose the characteristic temperatures of each of the enamels or to achieve the consecutivity of each step. b) from the highest transformation temperature to the lowest. Thus, it will prevent the enamel layers from being weakened and / or damaged. By way of example, it is preferred to use an enamel 41 which vitrifies at a lower temperature than the enamel 35, itself vitrifying at a lower temperature than the first enamel 33.

In order to allow sufficient printing precision, the phase c) is, preferably, carried out by pad printing or screen printing in order to deposit the contrasting layers 35, 37, 39, 41, 43, 45 with a different color to a greater or lesser extent. at the first enamel layer 33.

According to the invention after the steps a) and at least one step b), the method comprises a final step e) of completely covering said another layer of enamel 39 with a metal layer 38 to form, for example, the moon 13 , the stars 15 or constellations 23 or e ') consisting of covering only partially said another layer of enamel 37 with a metal layer 36 to form the moon 17 with the openwork face 14 or the stars 19 with the openwork centers 16 .

Preferably according to the invention, step e) or e ') comprises a first phase f) of covering the decoration or only a part with a solution of the colloidal type formed by a solvent and metal powder in suspension, then, a second phase g) of heating the part to evaporate the solvent and form a homogeneous metal layer. According to the invention, the metal powder may be based on a precious metal such as gold or platinum.

Of course, the present invention is not limited to the illustrated example but is susceptible of various variations and modifications that will occur to those skilled in the art. In particular, it is understood that the shapes and dimensions of the decorations can be completely different without this complicating the manufacturing process. The scope of the invention is defined only by the appended claims.

In addition, as explained above, the application of the invention can not be limited to the field of watchmaking but applies to the decoration of any enamelled piece suitable for a dial as, without limitation, a disk decorative embellished in a cufflink, in an earring or in a pendant.

Finally, it is obvious that a last layer may optionally be deposited by usual pad printing. For example, if a step e) was performed instead of a step e '), this last usual pad printing step could be used, for example, to draw a face on the moon 13.

Claims (15)

1. Enamelled part (3, 11, 21) for a dial comprising a ceramic substrate (31) coated with a first enamel layer (4', 12, 24, 33) to improve the appearance of said part, at least one other enamel layer (6', 8', 9, 14, 16, 25, 35, 37, 39, 41, 43, 45) partially covering the first enamel layer (4', 12, 24, 33), characterized in that said at least one other enamel layer (6', 8', 9, 14, 16, 25, 35, 37, 39, 41, 43, 45) is at least partially coated with a metallic layer (13, 15, 17, 19, 23, 36, 38) so that said decoration has a homogeneous reflection regardless of the incident light.
2. Part according to the preceding claim, characterized in that said at least one other layer (39) is totally coated with a metallic layer (13, 15, 23, 38).
3. Part according to claim 1 or 2, characterized in that said at least one other layer (6', 8', 14, 16, 25, 35, 37, 41, 43, 45) is of a different colour from the first enamel layer (4', 12, 24, 33).
4. Part according to claim 1 or 2, characterized in that said at least one other layer is of substantially identical colour (9, 39) to the first enamel layer.
5. Part according to any of the preceding claims, characterized in that said at least one other layer (37, 39) has a variable thickness in order to offer colour shading.
6. Part according to any of the preceding claims, characterized in that said decoration forms at least one alphanumerical symbol.
7. Part according to any of claims 1 to 5, characterized in that said decoration forms at least one drawing.
8. Timepiece characterized in that it includes at least one enamelled part according to any of claims 1 to 7.
9. Method of fabricating an enamelled part (3, 11, 21) for a dial comprising the following steps:

   a) providing a ceramic based substrate the visible portion (32) of which is coated with a first enamel layer (4', 12, 24, 33);

   b) selectively forming one other enamel layer (6', 8', 9, 14, 16, 25, 35, 37, 39, 41, 43, 45) on top of the first enamel layer (4', 12, 24, 33) so as to form a decoration on said visible surface;
   characterized in that it includes the following step:

   e')at least partially coating said one other enamel layer (6', 8', 9, 14, 16, 25, 35, 37, 39, 41, 43, 45) with a metallic layer (13, 15,17,19, 23, 36, 38) so that said decoration has a homogeneous reflection regardless of the incident light.
10. Method according to the preceding claim, characterized in that said at least one other layer (6', 8', 9, 14, 16, 25, 35, 37, 39, 41, 43, 45) has a variable thickness so as to offer colour shading.
11. Method according to claim 9 or 10, characterized in that step b) includes the following phases:

    c) selectively printing said decoration on said first enamel layer using a precursor solution of said one other enamel layer;

    d) heating the part to transform the precursor solution into enamel.
12. Method according to the preceding claim, characterized in that the transformation temperature of said one other enamel layer is at least 100°C lower than that of the first enamel layer to avoid damaging said first layer in each step b).
13. Method according to claim 11 or 12, characterized in that phase c) is achieved by pad printing or silk screen printing.
14. Method according to any of claims 9 to 13, characterized in that said one other layer (6', 8', 14, 16, 25, 35, 37, 41, 43, 45) is a different colour from the first enamel layer.
15. Method according to any of claims 9 to 13, characterized in that said one other layer (9, 39) is of substantially identical colour to the first enamel layer

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