Manufacturing method for watch parts

Abstract

To provide a method for manufacturing a three-dimensional horology component of a shape that is complex on a micrometric or nanometric scale.SOLUTION: A method for manufacturing a master pattern for a mold for a horology component at least comprises: an E1 step of manufacturing, from a first photosensitive resin, a first structure comprising at least one photosensitive resin layer comprising a first pattern obtained by polymerizing the first photosensitive resin by irradiation through at least one mask, and then developing the first photosensitive resin; and an E2 step of transforming the first structure into a second structure by structuring at least one surface of the first structure by addition of a second photosensitive resin to the at least one surface.SELECTED DRAWING: Figure 19

Description

[Technical field]

[0001] The present invention relates to a method for the manufacture of a master pattern intended to enable the manufacture of a mold for a watch component, and to a method for the manufacture of a watch component, in other words, to a method for the manufacture of a master pattern for a mold for a watch component, and to a method for the manufacture of a watch component. [Background technology]

[0002] Photolithography is a technique commonly used in the manufacture of watch components and in particular makes it possible to create the plastic moulds used in the manufacture of watch components.

[0003] US Pat. No. 5,399,633, for example, discloses the implementation of a method for manufacturing metallic parts having at least two layers using photolithographic techniques.

[0004] US Pat. No. 5,399,633 proposes an improved method for manufacturing multi-layer watch parts using photolithography techniques.

[0005] US Pat. No. 5,399,633 discloses a method for manufacturing a watch part made of polycrystalline ceramic, using a mold formed by photolithography.

[0006] These prior art approaches, based on so-called conventional photolithography, have the drawback that they are not capable of producing completely all three-dimensional shapes, such as complex shapes on the micrometer or nanometer scale.

[0007] Furthermore, the term "soft lithography" is used to describe a method that makes it possible to obtain a mold made of a soft material, for example from a master pattern produced using conventional photolithographic methods.

[0008] This method of the prior art has the drawback that it is not possible to produce completely all three-dimensional shapes, such as complex shapes on the micrometer or nanometer scale. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] European Patent Application Publication No. 2405300 [Patent Document 2] European Patent Application Publication No. 3035125 [Patent Document 3] European Patent Application Publication No. 3260932 [Patent Document 4] U.S. Patent No. 9,302,430 [Patent Document 5] International Publication No. 2017 / 102661 Summary of the Invention [Problem to be solved by the invention]

[0010] For this reason, one of the objects of the present invention is to improve the methods known from the prior art and to propose a solution for the production of three-dimensional watch components, possibly with complex shapes on the micrometer or nanometer scale. Another object of the present invention is to enable the production of watch components with high reliability, high reproducibility and high precision. [Means for solving the problem]

[0011] The invention therefore relates to a method for the manufacture of a master pattern intended to enable the manufacture of a mould for a watch component, and to a method for the manufacture of a watch component. The method for the manufacture of a master pattern for a mould for a watch component comprises at least the following steps: - manufacturing a first structure comprising at least one photosensitive resin layer from said first photosensitive resin, the first structure comprising a first pattern obtained by polymerizing said first photosensitive resin by irradiating through at least one mask and then developing said first photosensitive resin; and a step of transforming said first structure into a second structure by structuring said at least one surface of said first structure by adding a second photosensitive resin to said at least one surface, advantageously using a two-photon polymerization technique.

[0012] The invention is more particularly defined by the claims.

[0013] These objects, features and advantages of the present invention will be presented in more detail in the following description of particular embodiments, given by way of non-limiting example with reference to the accompanying drawings. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 shows a perspective view of an automatic device claw manufactured by a manufacturing method according to one embodiment of the present invention. [Diagram 2] FIG. 2 shows an enlarged perspective view of the opening of the automatic device jaw of FIG. 1 manufactured by a manufacturing method according to one embodiment of the present invention. [Diagram 3] FIG. 3 shows the successive steps of a method for the manufacture of a master pattern according to a first embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 4] FIG. 4 shows the successive steps of a method for the manufacture of a master pattern according to a first embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Diagram 5] FIG. 5 shows the successive steps of a method for the manufacture of a master pattern according to a first embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 6] FIG. 6 shows the successive steps of a method for the manufacture of a master pattern according to a first embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 7]FIG. 7 shows the successive steps of a method for the manufacture of a master pattern according to a first embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 8] FIG. 8 shows the successive steps of a method for the manufacture of a master pattern according to a first embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 9] FIG. 9 shows successive steps of a method for manufacturing the automated device jaw shown in FIGS. 1 and 2 according to a first embodiment of the invention. [Figure 10] FIG. 10 shows the steps of manufacturing a mold for an automated machine jaw, based on the master pattern resulting from the steps illustrated in FIGS. [Figure 11] FIG. 11 shows the steps of the manufacture of an automatic jaw, based in particular on the mould obtained at the end of the steps illustrated in FIG. [Figure 12] FIG. 12 shows successive steps of a method for the manufacture of a master pattern according to a second embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 13] FIG. 13 shows successive steps of a method for the manufacture of a master pattern according to a second embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 14] FIG. 14 shows successive steps of a method for the manufacture of a master pattern according to a second embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 15] FIG. 15 shows successive steps of a method for the manufacture of a master pattern according to a second embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 16] FIG. 16 shows successive steps of a method for the manufacture of a master pattern according to a second embodiment of the invention, intended to enable the manufacture of a mold for the automatic machine jaws shown in FIGS. [Figure 17]FIG. 17 shows the steps of manufacturing a mold for an automated tool jaw, based on the master pattern resulting from the steps shown in FIGS. [Figure 18] FIG. 18 shows the steps of the manufacture of a mold for an automatic device jaw, based in particular on the mold obtained at the end of the steps shown in FIG. [Figure 19] FIG. 19 illustrates a flow chart, which shows diagrammatically the steps and sub-steps of the first and second alternatives of the first embodiment. [Figure 20] FIG. 20 illustrates a flow chart, which shows diagrammatically the steps and sub-steps of the first, second and third alternatives of the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The invention advantageously implements a method for the manufacture of master patterns intended in particular to enable the manufacture of moulds for watch components, combining at least one step based on conventional photolithography with at least one step based on the two-photon polymerization technique known by the abbreviation TPP. For example, said method is used in a method disclosed in patent application WO 2005 / 023636, in a field far removed from watches. Finally, said method can be likened to a specific, three-dimensional, photolithographic method, totally different from conventional photolithography.

[0016] More specifically, the invention implements a manufacturing method comprising at least a first step E1 consisting of producing a first structure on a substrate using conventional photolithography techniques and a second step E2 consisting of converting the first structure into a second structure by structuring at least one surface of the first structure, advantageously using two-photon polymerization techniques.

[0017] In a first embodiment of the present invention, the manufacturing method further comprises, in addition to the first and second steps E1, E2, a third step E3, E3' consisting of producing a master pattern 2 intended to enable the manufacture of a mould 3 for a watch part 6; a fourth step E4 consisting of manufacturing said mold 3; a step E5 of manufacturing said watch part 6; Includes.

[0018] A manufacturing method according to a first alternative of the first embodiment of the invention is described in the context of the manufacture of an automaton jaw 6 illustrated in figures 1 and 2. The automaton jaw 6 is made of a ceramic, for example a technical ceramic, preferably yttria-stabilized zirconia, and comprises an opening 62, the walls of which comprise a microstructure 63 designed for example to reduce the contact area between the walls of the opening 62 of the jaw and the guiding means cooperating with the walls. The jaw, and in particular the microstructured walls of the opening 62, have a highly complex shape and can advantageously be obtained by the manufacturing method according to the first embodiment.

[0019] With reference to Figures 3 to 11, a first embodiment of a method for producing a master pattern intended to enable the production of a mold for a watch part, and a method for producing a watch part using a mold obtained from said master pattern, is described, which is particularly suitable for the production of the above-mentioned automatic mechanism claws, and more generally for the production of any watch part.

[0020] The method comprises a first step E1 consisting of producing a first structure 10 on a substrate 20, using conventional photolithographic techniques.

[0021] By convention, the horizontal direction is defined as the direction parallel to the plane of the substrate 20. The vertical direction is defined as the direction perpendicular to the horizontal direction, and therefore perpendicular to the plane of the substrate.

[0022] The substrate 20 may take the form of a metal wafer, such as stainless steel, or a silicon wafer, or a glass wafer, or a ceramic wafer. It is advantageously planar. The substrate may optionally comprise structures, for example produced by laser processing. These structures may for example comprise patterns, in particular processed patterns, and / or cavities. The substrate is prepared according to rules known to the skilled person, in particular with regard to degreasing, cleaning, possibly passivation and / or activation. If desired, the substrate 20 is provided with reference marks so that it can be positioned with high precision. The substrate 20 may be made of a conductive material, for example stainless steel. Alternatively, it is also possible to use a substrate made of a non-conductive material, for example silicon. In this case, a conductive layer 21 may be formed on the upper surface of the substrate 20 in a preparation step carried out before the first step E1, for example by means of thermal evaporation. In a known manner, the conductive starting layer 21 may comprise a sub-layer of chromium, nickel or titanium covered with a layer of gold or copper, and thus may present the form of a multi-layer structure.

[0023] The first step comprises a sub-step E11 consisting of forming a first photosensitive resin 31, according to rules known to the skilled person, so as to cover all or part of the conductive layer 21 of the substrate 20 over the desired height with a layer of the first photosensitive resin 31 (or directly covering the upper surface of the substrate 20 in the absence of the conductive layer 21). The first photosensitive resin 31 is suitable for conventional photolithography. The first photosensitive resin 31 may be negative or positive. In the former case, it is designed to be insoluble or barely soluble in a developer under the action of irradiation (i.e. the irradiated areas resist development), while in the latter case, it is designed to be soluble in a developer under the action of irradiation, while the parts not exposed to irradiation remain insoluble or barely soluble. Said photosensitive resin 31 may be of the SU-8 type, which is a negative photosensitive resin that is polymerized under the action of UV irradiation, for example the resin SU-8-100 resin from the company Microchem.

[0024] The first step then comprises a sub-step E12 consisting of exposing the first photosensitive resin 31 through a mask 4, in particular by means of UV radiation, X-ray radiation or an electron beam in a direction substantially perpendicular to the mask, in order to polymerize the first photosensitive resin according to a first pattern defined in the mask 4, as shown in FIG. 3. The exposure consists of exposing the layer of photosensitive resin 31 to light radiation through a mask 4 comprising openings and opaque areas, which thus defines the first pattern to be replicated to form the structure or part of the structure. The radiation used is perpendicular or substantially perpendicular to the plane in which the mask extends and also perpendicular or substantially perpendicular to the substrate 20, so that only the areas of the resin that are directly coincident with the openings formed in the mask are illuminated. These areas are thus defined by perpendicular or substantially perpendicular walls, i.e. walls perpendicular or substantially perpendicular to the plane of the substrate 20. Alternatively, a mask with a variation in transmittance may be used to form non-perpendicular or inclined walls.

[0025] The first step then comprises a sub-step E13 consisting of developing the first photosensitive resin 31. In an embodiment in which the resin 31 is a negative resin, the development consists of removing the non-exposed (i.e. non-irradiated) areas of the resin in a manner suitable for the photosensitive resin 31, for example by dissolving them with chemical products or by using a plasma process. Alternatively, in the case of a positive photosensitive resin, the irradiated areas are removed during development, for example via a chemical route, while the non-irradiated areas remain on the substrate. After development, the top surface of the substrate 20, or the optional conductive layer 21, is surfaced where the resin has been removed. The remaining parts of the resin thus form a first structure 10, as shown in FIG. 4. The structure rests on the top surface of the substrate 20, or on the conductive layer 21 of the substrate 20 in some cases. To this end, the first structure 10 comprises two horizontal surfaces, an upper (defined as the interface between the polymerized resin and air) and a lower (defined as the interface between the polymerized resin and the upper surface of the substrate 20 or the optional conductive layer 21), and generally substantially vertical, but alternatively may be inclined, side surfaces 11 extending between the two horizontal surfaces. These side surfaces are the result of openings formed in the first photosensitive resin 31 by removal of non-polymerized photosensitive resin using conventional photolithography. By preference, the first structure 10 has a constant height (measured between the two upper and lower surfaces).

[0026] To create a multi-layer structure, the first step E1 may involve repetition of the above-mentioned sub-steps with different masks having different first sub-patterns, resulting in the creation of a first structure having a first pattern corresponding to a combination of the various first sub-patterns.

[0027] The method then comprises a second step E2 consisting of transforming the first structure 10 into a second structure 1 by structuring at least one surface of the first structure 10, in particular at least one side surface 11 of the first structure 10. This step comprises adding to at least one surface a second three-dimensional pattern 12 in polymerized resin.

[0028] For this purpose, the second step comprises a sub-step E21 consisting of forming a layer of a liquid or semi-fluid second photosensitive resin 32 on at least a portion of at least one of the above-mentioned surfaces of the first structure 10, in particular on at least one side surface 11, as shown in FIG. 5. This step may be carried out, for example, by drop casting or by any other method allowing the application of a liquid or semi-fluid resin (spraying, spin coating, etc.). The second photosensitive resin 32 is particularly suitable for the two-photon polymerization technique mentioned above. The second photosensitive resin 32 may be negative or positive. In one particular embodiment, the photosensitive resin 32 used is a semi-fluid resin, for example the IP-Dip by Nanoscribe, which is a negative resin. TM The embodiment is not limited to the above description. Said surface of the first structure may alternatively or additionally be horizontal and is not limited to a lateral surface, especially in the case of the production of multi-layer watch parts.

[0029] Advantageously, the first and second photosensitive resins 31, 32 may be identical, in which case the resins used in the two steps E1, E2 are suitable for conventional photolithography and for two-photon polymerization.

[0030] The second step then comprises a sub-step E22 consisting of carrying out two-photon polymerization on at least a part of the layer of the second photosensitive resin 32, as shown in Fig. 6, in order to achieve a stereopolymerization according to a second predetermined stereopattern. For this purpose, the method may use a photonic device 5 intended to irradiate electromagnetic waves onto or into the photosensitive resin 32 in order to polymerize it according to spatial coordinates corresponding to the second pattern. The advantage of the method is the accuracy of the resolution and the complexity of the patterns that can be achieved, in particular vertically discontinuous patterns.

[0031] According to an advantageous embodiment, the photonic device 5 comprises an objective lens 51 at least partially immersed in the second photosensitive resin 32 for polymerization according to spatial coordinates defining the shape or volume 12 of the second pattern. This alternative advantageously allows optimizing the resolution of the second volumetric pattern. More specifically, the objective lens 51 is designed to guide and focus the laser beam 52 so that its focal point passes through the various spatial coordinates defining the contour or shape 12 of the second pattern. For each of the coordinates, two photons may be simultaneously absorbed in the resin 32 in a very small volume known as a "voxel" at the focal point of the laser 52. A chemical reaction is initiated and the liquid or semi-liquid resin is polymerized and hardened within the voxel. Thus, the voxels resulting from the path of the focal point of the laser beam 52 define the contour or shape 12 of the second pattern. Advantageously combining the focusing lens of the laser with the material of the photosensitive resin 32, the diameter of the voxels can be smaller than 0.1 μm, thus making it possible to define very high resolution micro- or nanostructures on at least one surface, and in particular on at least one side surface 11, of the first structure 10. 3 This allows the second pattern to be defined with a three-dimensional resolution of 0.1 μm or better and a lateral resolution equal to the diameter of a voxel, ie 0.1 μm or better.

[0032] In addition, the at least partial or complete immersion of the objective lens 51 in the second photosensitive resin 32 prevents the laser beam 52 from crossing the interface between the objective lens and the air and between the air and the second photosensitive resin, and avoids deflection of the laser beam at said interface. The laser beam (photon beam) interacts exclusively with the second photosensitive resin. The laser beam is processed in a continuous medium, avoiding any parasitic reflections, refractions or power losses. Thus, the path of the laser beam is minimized, making it easier to detect the already polymerized parts. Thus, the three-dimensional resolution of the second pattern is optimized and the processing speed is maximized.

[0033] Furthermore, as shown in FIG. 6, the second pattern may extend at least partially horizontally, or in a direction having a significant horizontal component, by application of a second photosensitive resin 32 to the side surface 11 of the first structure 10, in particular to a surface perpendicular or substantially perpendicular to the substrate 20.

[0034] The steps may thus form micro- or nanostructures, for example having the shape of square waves or steps 12 on the surface 11, as shown in Figure 7. The shapes are not cut into the surface 11 but are applied in relief on the surface 11.

[0035] The second step then comprises a sub-step E23 consisting of developing the second photosensitive resin 32 in order to remove the non-polymerized second photosensitive resin 32 and to obtain second structures 1 of the shape defined by the first and second patterns. In particular, once the second photosensitive resin 32 has been polymerized according to the predetermined three-dimensional shape, the areas of the photosensitive resin 32 that have not been exposed to light are removed, for example by dissolving in a chemical product or using a plasma process, in the case of a negative photosensitive resin. By preference, the chemical product used is the same as that used in the first step. It may be, for example, a PGMEA-based solvent.

[0036] At the end of this second step, the combination of the two photosensitive resins 31 , 32 , respectively shaped into the two above mentioned patterns, finally forms the second structure 1 attached to the substrate 20 .

[0037] According to the first embodiment, the second structure 1 is, together with the substrate 20, a substrate for the manufacture of a watch part. It is intended to form a first mould for the production of a master pattern from which a second mould is intended to be produced. In a first embodiment, the second structure may have at least one cavity 13.

[0038] As a result of steps E1, E2 of the method described above, it becomes possible to produce a second structure 1 having absolutely any complex three-dimensional shape, thus enabling the production of a master pattern for a mould for absolutely any watch part having a corresponding complex three-dimensional shape.

[0039] The manufacturing method then carries out a third step E3, E3' consisting of using the second structure 1 to manufacture a master pattern intended to manufacture a mould for the manufacture of a watch part.

[0040] More specifically, the third step E3, E3' consists of using the second structure 1 and the substrate 20 together as a mould for the manufacture of a master pattern 2 intended to manufacture a second mould 3 intended to directly manufacture a watch part 6.

[0041] The master pattern 2 may be made, inter alia, of a metal or a metal alloy or of a ceramic, or of a composite material.

[0042] According to a first alternative of the first embodiment, described below, the master pattern 2 is the result of growing a metal or metal alloy layer 22 on a substrate 20. For this reason, the master pattern preferably consists of the substrate 20, the layer 21, if present, and the metal or metal alloy layer 22 grown on the substrate. Alternatively, the master pattern 2 does not include the substrate 20 but has the shape of the metal or metal alloy layer 22 grown on the substrate, a layer previously separated from the substrate.

[0043] In a first alternative embodiment, the third step comprises a sub-step E31 consisting of forming, by electrodeposition or electroplating, in the cavity or cavities 13 of the second structure 1, at least partially forming the master pattern 2. In this sub-step, the aforementioned conductive layer 21 or the substrate 20 itself, if made of a conductive material, acts as a cathode to initiate the deposition reaction. This step uses, for example, the LIGA method and a metal or metal alloy, for example nickel (Ni) or nickel phosphorus (NiP) or any nickel-based alloy. Advantageously, the alloys described in US Pat. No. 5,999,333 can be used. The obtained metal layer 22 preferably has a height H equal to the height of the mold formed by the second structure 1. The metal layer 22 may also have a height less than or greater than the height of the mold. Optionally, this sub-step may comprise a height adjustment by simultaneous mechanical polishing of the metal layer and the mold, in order to obtain a perfectly planar horizontal top surface.

[0044] Furthermore, the resulting metal layer 22 preferably has a height H that is substantially greater than the height of layer 21. The height is greater than 5 times the height of layer 21, or greater than 10 times the height of layer 21.

[0045] In a first alternative form of this embodiment, the third step may include an optional substep E32 of separating the assembly formed of said metal layer 22 and the second structure 1 from the substrate 20, for example by peeling the conductive layer 21 from the substrate.

[0046] In a first alternative form of this embodiment, the third step comprises a sub-step E33 consisting of separating the master pattern 2 formed in particular of the metal layer 22 from the second structure 1, for example by means of a chemical attack or plasma, to obtain the result shown in FIG. 9.

[0047] The possible sub-steps E32 and E33 may be carried out in any order.

[0048] According to a second alternative of the first embodiment described below, the master pattern 2 is the result of the formation of a layer of ceramic on a substrate 20. For this reason, the master pattern is preferably composed of the substrate 20, the layer 21, if present, and the layer of ceramic formed on the substrate. Alternatively, the master pattern 2 does not include the substrate 20 but takes the form of a layer of ceramic grown on the substrate, a layer previously separated from the substrate.

[0049] In a second alternative of the embodiment, the third step E3' comprises a sub-step consisting of filling E31' the second structure 1 with a product comprising ceramic powder by means of a liquid path. The step may comprise, for example, injecting a slurry or injecting a gel or injecting a solid. Alternatively, the step may be carried out by means of electrophoresis in case of a substrate made of conductive material or if the top surface of the substrate is coated with a conductive layer 21. In case of a slurry, the slurry may comprise a liquid substance, a ceramic powder and at least one additive. The liquid substance may comprise water, an alcohol or another organic solvent. The ceramic powder may comprise, for example, zirconia or alumina or an oxide or a carbide or a nitride. The step may be carried out under vacuum to ensure a perfect filling without air inclusions.

[0050] Said substep E31' may be preceded by an optional substep consisting of preparing at least a surface portion of the substrate 20 facing the at least one cavity 13 of the second structure 1 or applying a coating to at least a surface portion of the substrate 20 facing the at least one cavity 13 of the second structure 1, with the aim of facilitating the future debinding of the blank of the master pattern 2 from the substrate 20. Said blank may for example be in the form of a green body, a precursor of the master pattern 2.

[0051] In a second alternative of said embodiment, the first step comprises a sub-step E32' consisting of consolidating the product placed on the second structure 1. Said sub-step may comprise, inter alia, drying of the slurry to obtain a blank of the master pattern 2.

[0052] An optional intermediate sub-step may consist of adjusting the height of the blank of the master pattern 2 before debinding the mould. Said blank may for example take the form of a green body, the precursor of the master pattern 2.

[0053] In a second alternative of said embodiment, the third step comprises a substep E33' consisting of separating the blank of the master pattern from the production mould formed by the second structure 1. Said separation may for example be achieved by chemical attack or by treatment with plasma.

[0054] In a second alternative of said embodiment, the third step finally comprises a sub-step E34' consisting of debinding the blank obtained in the previous step, followed by densification by sintering. Preferentially, the substrate 20 is made of a material intended to withstand the temperatures at which the sub-steps of the third step E3' are carried out. For example, the substrate may be made of silicon or alumina. Alternatively, the master pattern 2 does not include the substrate 20 but has the shape of a ceramic layer previously separated from the substrate.

[0055] According to an alternative to the first embodiment, the master pattern 2 may be at least partly made of a soft material such as an elastomer, for example and non-inclusively mention may be made of silicone, PDMS polydimethylsiloxane, rubber, polybutadiene, fluoroelastomers, etc.

[0056] Whatever the alternative of the first embodiment, the method for manufacturing a watch part comprises a fourth step E4 consisting of using the master pattern obtained in the method steps described above to manufacture a second mould 3. The second mould 3 is advantageously made of a soft material so as to allow it to be easily removed from the master pattern 2. The second mould 3 may for example be made of an elastomer, such as a polymer, in particular PDMS (polydimethylsiloxane) or silicone.

[0057] This step E4 comprises a first step consisting of enclosing E41 a volume intended to receive a volume 33 of elastomer, which is a precursor of the second mould 3, using the master pattern 2 and auxiliary means such as annular elements 7 which at least partially define the mould cavity of the mould.

[0058] This step E4 then comprises a second sub-step E42 consisting of pouring a volume 33 of elastomer into the mould cavity defined by the master pattern 2 and the annular element 7, as shown in FIG.

[0059] Said step E4 then comprises a third sub-step E43 consisting of polymerising the volume of elastomer 33 so as to solidify within the predefined mould cavity.

[0060] This step E4 then comprises a fourth sub-step E44 consisting of separating the elastomer mould 3 from the master pattern 2 and the annular element 7.

[0061] Whatever the alternative of the first embodiment, the method for producing a watch part then comprises a fifth step E5 consisting of producing a watch part 6 using the second mould 3.

[0062] Said step E5 comprises, for example, sub-steps E51, E52, E53, E54 similar to the sub-steps E31', E32', E33', E34' of step E3' of the second alternative of the first embodiment of the invention.

[0063] This step E5 includes, inter alia, the sub-steps consisting of filling E51 the mould 3 with a product comprising ceramic powder by means of a liquid path. This step may for example comprise injecting a slurry or injecting a gel or injecting a solid. In the case of a slurry, the slurry may comprise a liquid substance, a ceramic powder and at least one additive. The liquid substance may comprise water, an alcohol or another organic solvent. The ceramic powder may comprise, for example, zirconia or alumina or an oxide or a carbide or a nitride. This step may be carried out under vacuum to ensure a perfect filling without the inclusion of air.

[0064] Said substep E51 may be preceded by an optional substep consisting of preparing at least a surface part of the mould 3 or applying a coating to at least a surface part of the mould 3, with the aim of facilitating the future debinding of the blank of the part 6 from the mould 3. It is noted that said blank may for example be in the form of a green body, a precursor of the part 6.

[0065] Step E5 may then include in particular a sub-step consisting of E52 of consolidating the product placed in the mould 3. Said sub-step may in particular include drying of the slurry to obtain a blank of the part 6.

[0066] An optional intermediate sub-step may consist of adjusting the height of the blank of the part 6 before debinding the mould.

[0067] Step E5 may then include notably a sub-step E53 consisting of separating the blank of the part 6 and the mould 3. Said separation may for example be achieved by chemical attack or by treatment with plasma.

[0068] Step E5 may then include notably the sub-steps E54 consisting of debinding and densifying by sintering the blank of part 6 obtained in the previous step.

[0069] The watch component is preferably made of ceramic or composite materials. Such ceramic components are preferably made of ceramics known as technical ceramics. "Technical ceramics" is the name given to high-density materials based on aluminum oxide and / or on zirconium oxide and / or on zirconium oxide stabilized, in particular, by yttrium oxide and / or cerium oxide and / or magnesium oxide and / or made of strontium aluminate, in particular doped strontium aluminate, and / or made of nitrides and / or made of carbides, optionally colored, in particular, with metal oxides and / or mixed metal oxides and / or spinel phases. For ease of explanation, the term "ceramic" can be used to refer to the "technical ceramics" used to manufacture the component 6. A material is considered to be "high density" if its density is comprised between 95% and 100% of the theoretical density of the material in question. It is noted here that the idea of ​​"based on" means that the mentioned chemical components represent at least 50% by weight of the total chemical composition of the ceramic concerned. It is noted that the technical ceramics used to form the part are, in theory, different from the ceramics that might be used to form the mold.

[0070] In a second embodiment of the invention, the second structure 1 is intended to form, at least in part, a master pattern 2' of a mould 3' for the manufacture of a watch part 6. At the end of the second step E2, the combination of the two photosensitive resins 31, 32 respectively shaped into the two patterns mentioned above forms the second structure 1 attached to the substrate 20.

[0071] Figures 12 to 16 illustrate successive steps of a method for the manufacture of a master pattern 2', intended to enable the manufacture of a mould 3' for the automatic mechanism pawl illustrated in Figures 1 and 2, according to a second embodiment of the invention. Said second structure 1 is here intended to form, together with a substrate 20, a master pattern 2' for the manufacture of a mould 3' for a watch part 6. Alternatively, the master pattern 2' does not include any substrate 20 but takes the form of a second structure 1 previously separated from said substrate. Thus, unlike in the case of the first embodiment, here the second structure 1 directly forms the master pattern 2', rather than a mould for the manufacture of the master pattern.

[0072] In this second embodiment, the second structure 1 may include at least one cavity 13 .

[0073] In this second embodiment, the method for manufacturing a watch part comprises a third step E4', E4'', E4*, which uses the master pattern 2' to manufacture a mould 3', as illustrated in FIG.

[0074] According to a first alternative of the second embodiment, the mould 3' is advantageously made of a soft material so as to allow easy removal from the master pattern 2'. The second mould 3' may for example be made of an elastomer, such as a polymer, in particular PDMS (polydimethylsiloxane) or silicone.

[0075] According to a first alternative of said second embodiment, the method for manufacturing a watch part comprises a third step E4' consisting of using the master pattern 2' to manufacture a mould 3', as illustrated in figure 17. Step E4' may for example comprise sub-steps E41', E42', E43', E44' similar to the sub-steps E41, E42, E43, E44 of the above-mentioned step E4.

[0076] In the second and third alternatives of the second embodiment, the mould 3' may be rigid, in which case the master pattern 2' may be a sacrificial master pattern.

[0077] According to a second alternative of the second embodiment, the mould 3' is the result of growing a layer of metal or metal alloy on the substrate 20. For this, the mould 3' is preferably composed of the substrate 20, the layer 21, if present, and the layer of metal or metal alloy grown on the substrate. Alternatively, the mould 3' does not include the substrate 20 but has the shape of the layer of metal or metal alloy grown on the substrate, the layer being a layer previously separated from the substrate. The mould 3' now comprises at least one cavity.

[0078] According to a second alternative of the second embodiment, the third step E4'' consisting of using the master pattern 2' to manufacture a mould 3' comprises sub-steps E41'', E42'', E43'', similar to the sub-steps E31, E32, E33 of step E3 of the first alternative of the first embodiment of the present invention.

[0079] According to a third alternative of the second embodiment, the mould 3' is the result of the formation of a layer of ceramic on the substrate 20. For this, the mould 3' is preferably composed of the substrate 20, the layer 21, if present, and the layer of ceramic formed on the substrate. Alternatively, the mould 3' does not include the substrate 20 but has the shape of a layer of ceramic on a substrate, the layer being a layer previously separated from the substrate. The mould 3' now comprises at least one cavity.

[0080] According to a third alternative of the second embodiment, the third step E4* consisting of using the master pattern 2' to manufacture a mould 3' includes sub-steps E41*, E42*, E43* and E44* similar to the sub-steps E31', E32', E33' and E34' of step E3' of the second alternative of the first embodiment of the present invention.

[0081] Whatever the alternative of the second embodiment, the method for producing a watch part then comprises a fourth step E5' consisting of producing a watch part 6 using the mould 3'.

[0082] Step E5' may include notably sub-steps E51', E52', E53', E54' similar to the sub-steps E51, E52, E53, E54 of step E5 described above.

[0083] In the case of a rigid mould 3', the part 6 or the blank of the part 6 can be removed from the mould 3' by taking advantage of the shrinkage of the material from which the part or the blank of the part 6 is made.

[0084] The manufacturing method of the above-mentioned timepiece parts may be used for the manufacture of all timepiece parts, such as, by way of illustrative and non-limiting example, balances, anchors, jumpers, pinions, gears, levers, springs, cams or blanks. The manufacturing method may in particular be used for the manufacture of any element that necessarily includes a microstructure.

[0085] It is therefore clear that the invention achieves the desired objective by advantageously combining two different techniques: traditional photolithography allows in a first step to form the main volume of a master pattern intended to allow the manufacture of a mold for a watch part to be made simply, quickly and reliably, and the two-photon polymerization technique allows in a second, more complex and less rapid, but more precise and flexible step to add complex shapes to said main volume, thus allowing any three-dimensional pattern to be perfectly defined. This results in a master pattern for a mold for a watch part, complex in shape and manufactured in a simple and robust way. [Explanation of symbols]

[0086] 1 Second structure 2 Master Pattern 3. Mold 4. Mask 5 Photon Device 6. Watch Parts 7 Circular Elements 10 1st structure 11 Side 13 Cavity 20 Substrate 21 Conductive layer 22 Metal layer 31 First photosensitive resin 32 Second photosensitive resin

Claims

1. A method for manufacturing a master pattern for a watch component mold formed using a second structure, the method comprising at least: A step (E1) of producing a first structure comprising at least one photosensitive resin layer from said first photosensitive resin, said first structure comprising a first pattern obtained by polymerizing said first photosensitive resin by irradiating through at least one mask and then developing said first photosensitive resin; A step (E2) of transforming the first structure into the second structure by structuring said at least one surface of said first structure by adding a second photosensitive resin to said at least one surface, said step consisting of transforming (E2) the first structure, forming (E21) a layer of said second photosensitive resin on at least a portion of said at least one surface of said first structure; carrying out a two-photon polymerization on the second photosensitive resin using a photonic device including an objective lens at least partially immersed in the second photosensitive resin to guide and focus a laser beam on voxels that define the contour and / or shape of a second pattern, while preventing the laser beam from crossing the interface between the objective lens and air and between air and the second photosensitive resin (E22), in order to obtain a three-dimensional polymerization based on the second pattern; The second photosensitive resin is removed, and the first and second patterns are formed. developing (E23) to obtain a 2 structure; and Including, The first photosensitive resin is an SU-8 type or an SU-8-100 type, and the second photosensitive resin is a liquid or semi-liquid resin different from the first photosensitive resin; The step of performing two-photon polymerization (E22) includes polymerizing and hardening the liquid or semi-liquid resin of the second photosensitive resin in the voxel by the laser beam focused by the objective lens, thereby forming a 0.001 μm ３ or better three-dimensional resolution and / or a lateral resolution of 0.1 μm or better.

2. The step of transforming (E2) the first structure includes adding the second photosensitive resin onto at least one side of the first structure. A method for producing a master pattern for a mold for a watch part according to claim 1.

3. The step consisting of exposing (E12) the first photosensitive resin to light produces first structures with lateral sides perpendicular or substantially perpendicular to the substrate and / or of constant cross-sectional area parallel or substantially parallel to the substrate, A method for producing a master pattern for a mold for a watch part according to claim 1 or 2.

4. The two resins are positive or negative, A method for producing a master pattern for a mold for a watch component according to any one of claims 1 to 3.

5. The method comprises: A step (E31) of applying, by electrochemical deposition or electroplating, a metal layer on said second structure, which at least partially forms said master pattern of the mold for the watch part; A step (E33) of separating the master pattern of the mold for the watch part formed from the metal layer from the second structure, Including, A method for producing a master pattern for a mold for a watch component according to any one of claims 1 to 4.

6. The metal of the metal layer is a nickel-based or nickel-phosphorus alloy; A method for producing a master pattern for a mold for a watch part according to claim 5.

7. A step (E31') of filling said second structure with a product comprising a ceramic powder, by means of a fluid path; A step of consolidating (E32') said products; A step (E33') of separating the blank formed by said product from said second structure; a step (E34') of debinding said blank obtained in the previous step and then densifying it by sintering; Including, A method for producing a master pattern for a mold for a watch component according to any one of claims 1 to 4.

8. The second structure directly forms the master pattern of a mold for a watch part. A method for producing a master pattern for a mold for a watch component according to any one of claims 1 to 4.

9. The method comprises the steps of producing a master pattern (2; 2') using the method according to any one of claims 1 to 8, using said master pattern for producing (E4; E4'; E4''; E4*) a watch part mould (3; 3'), and then using said watch part mould (3; 3') as a production mould for producing (E5; E5') a watch part, said watch part being made of ceramic, Manufacturing method for watch parts.

10. said watch part mould (3;3') is made of polymer; A method for manufacturing a watch component according to claim 9.

11. said step consisting of using said master pattern for manufacturing (E4;E4') said watch part mould (3:3'), a sub-step (E41; E41') of enclosing, with an annular element (7), a volume intended to receive a volume of polymer, to complement said master pattern (2; 2'); a sub-step (E42; E42') of pouring a volume of elastomer into the mould cavity formed by said master pattern (2; 2') complemented by said annular elements (7); a sub-step (E43; E43') of polymerizing the volume of said elastomer to harden said elastomer; a sub-step (E44; E44') of separating said watch part mould (3; 3') from said master pattern (2; 2') and from said annular element (7), Including, A method for manufacturing a watch component according to claim 10.

12. Method for manufacturing a watch part according to claim 9, characterized in that the mould for the watch part (3; 3') is made of metal or a metal alloy or of ceramic.

13. Said step consisting of manufacturing (E5; E5') said timepiece part, a sub-step (E51; E51') of filling said watch part mould (3; 3') with a product comprising ceramic powder, by means of a liquid passage; a sub-step of fixing said product (E52; E52'), The blank formed by the product is separated from the mold for the watch part (3; 3') (E5 and a sub-step (E54, E54') of debinding the blanks obtained in the sub-step of separating the blanks and then densifying them by sintering, The present invention relates to a method for producing a watch part from technical ceramics using the same. A method for manufacturing a watch component according to any one of claims 9 to 12.

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