METHOD FOR MANUFACTURING A WATCH COMPONENT

Description

[0001] The present invention relates to a method for manufacturing a master intended to enable the manufacturing of a watch component mold, and a method for manufacturing a watch component. In other words, the present invention relates to a method for manufacturing a master for a watch component mold and a method for manufacturing a watch component.

[0002] Photolithography is a technology commonly used for the manufacture of watch components, particularly for forming a resin mold used for the manufacture of watch components.

[0003] Patent EP2405300 describes, for example, the production of a method for manufacturing a metal part on at least two levels using photolithography technology.

[0004] Document EP3035125 proposes an improved method for manufacturing a watch component having several levels using photolithography technology.

[0005] Document EP3260932 describes a method for manufacturing a polycrystalline ceramic watch component, in which a mold formed by photolithography is used.

[0006] These state-of-the-art approaches based on so-called traditional photolithography, however, have the disadvantage of not allowing the creation of any three-dimensional shape, such as complex shapes on a micrometric or even nanometric scale.

[0007] Furthermore, the term "soft-lithography" is used to describe a process for obtaining a mold made of a flexible material from a master manufactured, for example, by a traditional photolithography process.

[0008] Such a prior art method, however, has the disadvantage of not allowing the production of any three-dimensional shape, such as complex shapes on a micrometric or even nanometric scale. WO 2017 / 148394 A1 describes a method in which a photoresist is covered by a photomask during a photolithography process. The exposed photoresist then provides a support structure for the following two-photon absorption laser writing step. A laser beam from a two-photon absorption laser writing device is used to expose the outline of a component, in this example the outline of the shape of a balance screw. Once the patterned substrate has been baked, the photoresist that has been exposed by the two-photon laser beam along the outline of the balance screw will be crosslinked, so as to form a closed shell.The photoresist is then developed in a developer, resulting in a photoresist mold with the geometric characteristics required for the balancing screw. The substrate is then ready to be placed in an electroforming tank.

[0009] Thus, the present invention aims to improve the known methods of the prior art and to propose a solution for manufacturing a three-dimensional watch component, possibly of complex shape on a micrometric or even nanometric scale. It also aims to enable the manufacture of a watch component with high reliability, high repeatability, and high precision.

[0010] To this end, the invention relates to a method for manufacturing a master intended to enable the manufacturing of a watch component mold, and a method for manufacturing a watch component.

[0011] The manufacturing process of a master for a watch component mold includes, among other things, the following steps: Manufacturing a first structure from a first photosensitive resin comprising at least one layer of photosensitive resin comprising a first pattern obtained by polymerization of the first photosensitive resin by irradiation through at least one mask, then development of said first photosensitive resin; Transforming the first structure into a second structure by structuring at least one surface of the first structure by adding a second photosensitive resin to said at least one surface. This step advantageously uses two-photon polymerization technology.

[0012] The invention is defined by claim 1.

[0013] These objects, characteristics and advantages of the present invention will be explained in detail in the following description of particular embodiments made without limitation in relation to the attached figures among which: There figure 1 represents a perspective view of an automaton ratchet produced by a manufacturing method according to an embodiment of the invention. The figure 2 represents an enlarged perspective view of an opening of the ratchet of the figure 1 , produced by a manufacturing method according to an embodiment of the invention. The figures 3 to 9 illustrate the successive stages of a manufacturing process for a master intended to enable the manufacturing of a mold of the automaton pawl represented by the Figures 1 and 2 according to a first embodiment of the invention. The figure 10illustrates a step in manufacturing a mold of the automaton pawl on the basis of said master resulting from the steps illustrated by the figures 3 to 9 . There figure 11 illustrates a step in the manufacture of the automaton ratchet based on the mold obtained in particular at the end of the step illustrated by the figure 10 . THE figures 12 to 16 illustrate the successive stages of a manufacturing process for a master intended to enable the manufacturing of a mold of the automaton pawl represented by the Figures 1 and 2 according to a second embodiment of the invention. The figure 17 illustrates a step in manufacturing a mold of the automaton pawl on the basis of said master resulting from the steps illustrated by the figures 12 to 16 . There figure 18 illustrates a step in the manufacture of the automaton ratchet based on the mold obtained in particular at the end of the step illustrated by the figure 17 . There figure 19illustrates a flowchart schematically representing the steps and sub-steps of the first and second variants of the first embodiment. The figure 20 illustrates a flowchart schematically representing the steps and sub-steps of the first, second and third variants of the second embodiment.

[0014] The invention notably implements a method for manufacturing a master intended to enable the manufacturing of a watch component mold, which advantageously combines at least one step based on traditional photolithography and at least one step based on two-photon polymerization technology, known by its English acronym TPP for "two-photon polymerization". This method is, for example, used in the method described by document US9302430, in a field far removed from watchmaking. It is ultimately similar to a particular, three-dimensional photolithography, very different from traditional photolithography.

[0015] More particularly, the invention implements a manufacturing method comprising at least a first step consisting of manufacturing E1 a first structure on a substrate, using traditional photolithography technology, and a second step advantageously consisting of transforming E2 the first structure into a second structure, by structuring at least one surface of the first structure using two-photon polymerization technology.

[0016] In a first embodiment of the invention, the manufacturing method comprises, in addition to the first and second steps E1 and E2: A third step consisting of manufacturing E3, E3' a master 2 intended to allow the manufacturing of a mold 3 of watch component 6; A fourth step consisting of manufacturing E4 said mold 3; And a step consisting of manufacturing E5 said watch component 6.

[0017] The manufacturing method according to a first variant of the first embodiment of the invention will be illustrated in the context of the manufacturing of an automaton pawl 6 represented by the Figures 1 and 2 . This automaton pawl 6 is, for example, made of a technical ceramic, preferably a ceramic such as yttria-containing zirconia, and comprises an opening 62 whose wall comprises microstructures 63 which are adapted to reduce, for example, the contact surfaces between said wall of the opening 62 of the pawl and the guide means with which it cooperates. This pawl, and in particular the microstructured wall of the opening 62, has a very complex geometry, which can advantageously be obtained by the manufacturing method according to the first embodiment.

[0018] We will now describe a first embodiment of a method for manufacturing a master intended to enable the manufacturing of a watch component mold, and a method for manufacturing a watch component using the mold obtained from said master, with reference to the figures 3 to 11 , particularly suitable for the manufacture of an automaton ratchet as described above, and more generally suitable for the manufacture of any watch component.

[0019] The method comprises a first step consisting of manufacturing E1 a first structure 10 on a substrate 20, using traditional photolithography technology.

[0020] By convention, we define the horizontal direction as a direction parallel to the plane of the substrate 20. We define the vertical direction as the direction perpendicular to the horizontal direction, therefore perpendicular to the plane of the substrate.

[0021] This substrate 20 may be in the form of a metal wafer, such as stainless steel, or in the form of a silicon, glass or ceramic wafer. It is advantageously planar. It may optionally comprise structures which are produced, for example, by laser machining. These structures may, for example, comprise patterns, in particular machined patterns, and / or cavities. The substrate is prepared according to the rules known to those skilled in the art, in particular for its degreasing, cleaning, possibly its passivation and / or its activation. Preferably, the substrate 20 is provided with markers so that it can be positioned very precisely. The substrate 20 may be made of a conductive material, for example stainless steel. Alternatively, a substrate made of a non-conductive material, such as silicon, could also be used.In this case, a conductive layer 21 may be deposited on the upper surface of the substrate 20, for example by thermal evaporation, in a preliminary step implemented before the first step E1. In a known manner, this conductive priming layer 21 may comprise a sub-layer of chromium, nickel or titanium covered with a layer of gold or copper, and thus be in the form of a multi-layer structure.

[0022] The first step comprises a substep consisting of depositing E11 a first photosensitive resin 31 so as to cover all or part of the conductive layer 21 of the substrate 20 (or directly the upper surface of the substrate 20 in the absence of a conductive layer 21) with a layer of a first photosensitive resin 31 over a desired height, according to the rules known to those skilled in the art. This first photosensitive resin 31 is suitable for traditional photolithography. It can be negative or positive. In the first case, it is designed to become insoluble or difficult to dissolve in a developer under the action of radiation (i.e. the exposed areas resist development), whereas, in the second case, it is designed to become soluble in a developer under the action of radiation, while the part not exposed to the radiation remains insoluble or difficult to dissolve.This photosensitive resin 31 can be of the “SU-8” type, which is a negative photosensitive resin which polymerizes under the action of UV radiation, for example the SU-8-100 resin from Microchem.

[0023] The first step then comprises a sub-step consisting of exposing E12 the first photosensitive resin 31 through a mask 4, in particular by UV radiation, X-rays or an electron beam, in a direction substantially perpendicular to the mask, to polymerize it according to a first pattern defined by the mask 4, as illustrated by the figure 3. This exposure consists of exposing to light radiation or insolating the photosensitive resin layer 31 through the mask 4 comprising openings and opaque zones. This mask thus defines the first pattern to be reproduced for the production of the structure or a portion of structure. The radiation used is perpendicular or substantially perpendicular to the plane in which the mask extends, and perpendicular or substantially perpendicular to the substrate 20, so as to irradiate only the zones of the resin located at the right angle to the openings made in the mask. These zones are thus defined by vertical or substantially vertical walls, namely perpendicular or substantially perpendicular to the plane of the substrate 20. Alternatively, a mask with transmittance variation can be used so as to form non-vertical or inclined walls.

[0024] Then, the first step comprises a substep consisting of developing E13 the first photosensitive resin 31. In the embodiment where the resin 31 is negative, the development consists of removing the unexposed (i.e., non-exposed) resin areas, according to a method adapted to the photosensitive resin 31, for example by dissolution with a chemical product or by a plasma method. Alternatively, in the case of a positive photosensitive resin, the exposed areas are removed during development, for example chemically, and the non-exposed areas are retained on the substrate. After development, the upper surface of the substrate 20 or the optional conductive layer 21 appears at the locations where the resin has been removed. The remaining parts of resin thus form a first structure 10, illustrated by the figure 4. This structure rests on the upper surface of the substrate 20 or of the optional conductive layer 21 of the substrate 20. The first structure 10 therefore extends between two horizontal surfaces, upper (defined as the interface between the polymerized resin and the air) and lower (defined as the interface between the polymerized resin and the upper surface of the substrate 20 or of the optional conductive layer 21), and comprises lateral surfaces 11, extending between these two horizontal surfaces, generally substantially vertical but which may alternatively be inclined. These lateral surfaces result from the openings formed in the first photosensitive resin 31 by the removal of unpolymerized photosensitive resin, by traditional photolithography. Preferably, the first structure 10 has a constant height (measured between the two upper and lower surfaces).

[0025] In order to create a multi-level structure, the first step E1 may comprise the repetition of the sub-steps described previously, with different masks, representing different sub-first patterns, the result of which represents the first structure according to a first pattern corresponding to the association of the different sub-first patterns.

[0026] The method then comprises a second step consisting of transforming E2 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 lateral surface 11 of the first structure 10. This step comprises the addition of a second three-dimensional pattern 12 in polymerized resin on said at least one surface.

[0027] The second step thus comprises a sub-step consisting of depositing E21 a layer of a second liquid or semi-liquid photosensitive resin 32 on at least a portion of the at least one aforementioned surface of the first structure 10, in particular on at least one lateral surface 11, as illustrated by the Figure 5. This step can, for example, be carried out by "drop casting" or any other means allowing the depositing of liquid or semi-liquid resin ("spray coating", "spin coating", etc.). The second photosensitive resin 32 is particularly suitable for the two-photon polymerization technology mentioned above. It can be negative or positive. In a particular embodiment, the photosensitive resin 32 used is a semi-liquid resin, for example an IP-Dip ™ resin from Nanoscribe, which is a negative resin. The embodiment is not limited to the above description. The aforementioned surface of the first structure could alternatively or additionally be horizontal, and not only a lateral surface, in particular in the case of manufacturing a multi-level watch component. Alternatively, the first and second photosensitive resins 31, 32 can be identical.The resin then used for the two steps E1, E2 is suitable for both traditional photolithography and two-photon polymerization technology.

[0028] The second step then comprises a substep consisting of two-photon polymerizing E22 at least a portion of the layer of the second photosensitive resin 32, as illustrated by the figure 6 , to obtain a three-dimensional polymerization according to a second predefined three-dimensional pattern. For this, the method can use a photonic device 5, which is designed to emit electromagnetic waves onto or into the photosensitive resin 32, so as to polymerize it according to spatial coordinates which correspond to the second pattern. The advantages of this method are the precision of the definition and the complexity of the patterns that can be produced, such as in particular non-continuous patterns in the vertical direction.

[0029] According to the invention, the photonic device 5 comprises an objective 51 which is at least partially immersed in the second photosensitive resin 32 so as to polymerize it according to spatial coordinates defining the three-dimensional shape or geometry 12 of the second pattern.

[0030] This advantageously makes it possible to optimize the resolution of the second three-dimensional pattern. More particularly, the objective 51 is provided to direct and focus a laser beam 52 so that the focal point passes through the different spatial coordinates defining the shape or geometry 12 of the second pattern. For each of the coordinates, two photons can simultaneously be absorbed by the resin 32 in a very small volume called a "voxel" at the focal point of the laser 52. A chemical reaction is initiated, the liquid or semi-liquid resin polymerizes and becomes solid inside the voxel. The voxels resulting from the focusing path of the laser beam 52 thus define the shape or geometry 12 of the second pattern. By advantageously combining the focusing optics of the laser and the material of the photosensitive resin 32, the diameter of the voxel can be less than 0.1 µm, and therefore makes it possible to define microstructurations or even nanostructurations of very high resolution on the at least one surface, in particular on the at least one lateral surface 11, of the first structure 10. This step thus makes it possible to define a second pattern according to a three-dimensional resolution less than or equal to 0.001 µm 3< and a lateral resolution equivalent to the diameter of the voxel, i.e. less than or equal to 0.1 µm.

[0031] On the other hand, as represented by the figure 6 , this second pattern can extend at least partly in a horizontal direction, or having a significant horizontal component, from a deposit of second photosensitive resin 32 on a lateral surface 11 of the first structure 10, in particular on a surface perpendicular or substantially perpendicular to the substrate 20.

[0032] This step can therefore form microstructures, or even nanostructures, which can, for example, take the form of crenellations or stairs 12 on the surface 11, as illustrated by the figure 7 These shapes do not hollow out the surface 11, but are arranged in relief on the surface 11.

[0033] The second step then comprises a substep consisting of developing E23 the second photosensitive resin 32 to eliminate the second unpolymerized photosensitive resin 32 and obtain the second structure 1 of shape defined by the first and second patterns. Indeed, once the second photosensitive resin 32 has been polymerized according to the predefined three-dimensional geometry, the unexposed areas of photosensitive resin 32 are eliminated in the case of a negative photosensitive resin, for example by dissolution with a chemical product or by a plasma process. Preferably, the chemical product used is the same as that used during the first step. This may, for example, be a PGMEA-based solvent.

[0034] At the end of this second step, the assembly of the two photosensitive resins 31, 32 shaped respectively according to the two aforementioned patterns finally forms a second structure 1 secured to the substrate 20.

[0035] According to the first embodiment, this second structure 1 is intended to form, in addition to the substrate 20, a first mold for manufacturing a master intended to manufacture a second mold for manufacturing a watch component. In this first embodiment, the second structure 1 may comprise at least one cavity 13.

[0036] Due to the steps E1, E2 of the method described above, it is possible to form a second structure 1 having any complex three-dimensional shape, and therefore consequently making it possible to form any master for a watch component mold of corresponding complex three-dimensional shape.

[0037] The method then implements a third step consisting of using E3, E3' the second structure 1 to manufacture a master intended to manufacture a mold for manufacturing a watch component.

[0038] More particularly, this third step E3, E3' consists of using the second structure 1, in addition to the substrate 20, as a mold for the manufacture of a master 2 intended to manufacture a second mold 3 intended for the direct manufacture of a watch component 6.

[0039] This master 2 may in particular comprise metal or a metal alloy, or ceramic or a composite material. Preferably, the master 2 comprises the substrate 20.

[0040] According to a first variant described below of the first embodiment, the master 2 results from a growth of a layer 22 of metal or of a metal alloy on the substrate 20. Thus, the master is preferably made up of the substrate 20, of the possible layer 21, and of the layer 22 of metal or of the metal alloy having grown on said substrate. Alternatively, the master 2 does not comprise the substrate 20 and takes the form of the layer 22 of metal or of the metal alloy having grown on the substrate, the latter being previously separated from said substrate.

[0041] In this first variant embodiment, the third step comprises a sub-step consisting of depositing E31 a layer of metal 22 forming at least partially the master 2, by electrodeposition or galvanic deposition, in the cavity or cavities 13 of the second structure 1, as illustrated by the figure 8. In this sub-step, the aforementioned conductive layer 21 or the substrate 20 itself if it is made of a conductive material, acts as a cathode to initiate the deposition. This step uses, for example, the LIGA process and a metal or a metal alloy such as, for example, nickel (Ni) or nickel-phosphorus (NiP) or any nickel-based alloy. Advantageously, an alloy such as described by document WO2017102661 may be used. The metal layer 22 obtained preferably has the same height H as that of the mold formed by the second structure 1. It may also have a height less than the height of the mold, or even a height greater than the height of the mold. Optionally, this sub-step may include a height adjustment, by simultaneous mechanical polishing of the metal layer and the mold, to obtain a perfectly flat, horizontal upper surface.

[0042] Furthermore, the metal layer 22 obtained preferably has a height H significantly greater than that of the layer 21. It is preferably greater than five times the height of the layer 21, or even greater than ten times the height of the layer 21.

[0043] In this first embodiment variant, the third step may comprise an optional sub-step consisting of separating E32 the assembly formed by said metal layer 22 and the second structure 1 from the substrate 20, for example by delamination of the conductive layer 21 from the substrate.

[0044] In this first embodiment variant, the third step comprises a sub-step consisting of separating E33 the master 2, formed in particular by said metal layer 22, from the second structure 1, for example by chemical attack or using a plasma, to achieve the result represented by the figure 9 .

[0045] The possible sub-step E32 and sub-step E33 can be carried out in any order.

[0046] According to a second variant described below of the first embodiment, the master 2 results from the formation of a ceramic layer on the substrate 20. Thus, the master is preferably made up of the substrate 20, of the possible layer 21, and of the ceramic layer formed on said substrate. Alternatively, the master 2 does not comprise the substrate 20 and takes the form of the ceramic layer on the substrate, the latter being previously separated from said substrate.

[0047] In this second embodiment variant, the third step E3' comprises a sub-step consisting of filling E31' the second structure 1 by liquid means with a product comprising ceramic powder. This step may, for example, comprise the casting of a slip or the casting of a gel or a coagulation casting. Alternatively, this step may be implemented by electrophoresis in the case of a substrate made of a conductive material or whose upper surface of the substrate is covered with a conductive layer 21. In the case of a slip, the latter may comprise a liquid material, ceramic powder and at least one additive. The liquid material may comprise water, an alcohol or another organic solvent. The ceramic powder may, for example, comprise a zirconia, or an alumina, or an oxide, or a carbide, or a nitride. This step may be carried out under vacuum to ensure perfect filling without air inclusion.

[0048] This sub-step E31' may be preceded by an optional sub-step consisting of preparing at least one portion of substrate surface 20 facing at least one cavity 13 of the second structure 1 or depositing a coating on at least one portion of substrate surface 20 facing at least one cavity 13 of the second structure 1, with the aim of facilitating the future release of a blank of the master 2 from the substrate 20. As a remark, this blank may, for example, take the form of the green body prefiguring the master 2.

[0049] In this second embodiment variant, the third step comprises a sub-step consisting of consolidating E32' the product positioned in the second structure 1. This sub-step may in particular comprise the drying of the slip in order to obtain a rough draft of the master 2.

[0050] An optional intermediate sub-step may consist of adjusting the height of the master 2 rough, before releasing it from the mold. This rough may, for example, take the form of the green body prefiguring the master 2.

[0051] In this second embodiment, the third step comprises a sub-step consisting of separating E33' the master blank from the manufacturing mold formed by the second structure 1. This separation can, for example, be carried out by chemical attack or by treatment using a plasma.

[0052] In this second embodiment variant, the third step finally comprises a sub-step consisting of debinding the blank obtained in the previous step and then densifying it E34' by sintering. Preferably, the substrate 20 is made of a material designed 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 2 does not comprise the substrate 20 and takes the form of the ceramic layer previously separated from said substrate.

[0053] According to an alternative variant of the first embodiment, the master 2 may be made at least partially of a flexible material such as an elastomer. For example, and in a non-exhaustive manner, we can cite silicone, PDMS PolyDimethylSiloxane, rubber, polybutadiene, fluoroelastomer, etc.

[0054] Whatever the embodiment variant of the first embodiment, the method for manufacturing a watch component comprises a fourth step consisting of using E4 the master obtained by the steps of the method described previously to manufacture a second mold 3. This second mold 3 is advantageously made of a flexible material so that it can be easily removed from the master 2. This second mold 3 can, for example, be made of a polymer, in particular an elastomer such as PDMS (Polydimethylsiloxane) or silicone.

[0055] This step E4 comprises a first sub-step consisting of circumscribing E41 a volume intended to receive a volume 33 of elastomer which prefigures the second mold 3 by means of the master 2 and an ancillary means such as an annular element 7, which at least partially define the imprint of the mold.

[0056] This step E4 then comprises a second sub-step consisting of pouring E42 the volume 33 of elastomer into the imprint defined by the master 2 and the annular element 7, as illustrated by the figure 10 .

[0057] This step E4 then comprises a third sub-step consisting of crosslinking E43 the volume of elastomer 33 so as to solidify it in the previously defined imprint.

[0058] This step E4 then includes a fourth sub-step consisting of separating E44 the elastomer mold 3 from the master 2 and the annular element 7.

[0059] Whatever the embodiment variant of the first embodiment, the method for manufacturing a watch component then comprises a fifth step consisting of manufacturing E5 a watch component 6 using the second mold 3.

[0060] This step E5 comprises, for example, sub-steps E51, E52, E53, E54 which are similar to sub-steps E31', E32', E33', E34' of step E3' of the second variant of the first embodiment of the invention.

[0061] This step E5 may in particular comprise a sub-step E51 consisting of filling the mold 3 by liquid means with a product comprising ceramic powder. This step may, for example, comprise the casting of a slip or the casting of a gel or a coagulation casting. In the case of a slip, the latter may comprise a liquid material, ceramic powder and at least one additive. The liquid material may comprise water, an alcohol or another organic solvent. The ceramic powder may, for example, comprise a zirconia, or an alumina, or an oxide, or a carbide, or a nitride. This step may be carried out under vacuum to guarantee perfect filling without air inclusion.

[0062] This sub-step E51 may be preceded by an optional sub-step consisting of preparing at least a surface portion of the mold 3 or depositing a coating on at least a surface portion of the mold 3, with the aim of facilitating the future release of a blank of the component 6 from the mold 3. As a note, this blank may, for example, take the form of the green body prefiguring the component 6.

[0063] Step E5 may then in particular comprise a sub-step consisting of consolidating E52 the product positioned in the mold 3. This sub-step may in particular comprise the drying of the slip in order to obtain a rough copy of the component 6.

[0064] An optional intermediate sub-step may consist of setting the height of the rough part of component 6, before releasing it from the mold.

[0065] Step E5 may then in particular comprise a sub-step E53 consisting of separating the component blank 6 from the mold 3. This separation may, for example, be carried out by chemical attack or by treatment using a plasma.

[0066] Step E5 may then in particular comprise a sub-step consisting of debinding the component blank 6 obtained in the previous step and densifying it E54 by sintering.

[0067] The watch component is preferably made of a ceramic or composite material. Such a ceramic component is preferably made of so-called technical ceramic. By "technical ceramics" we mean dense materials based on aluminum oxide; and / or zirconium oxide; and / or zirconium oxide stabilized in particular with yttrium oxide and / or cerium oxide and / or magnesium oxide; and / or strontium aluminate in particular doped; and / or nitrides; and / or carbides; and optionally be pigmented in particular by metal oxides and / or mixed metal oxides and / or spinel phases. To simplify the description, we can use the term "ceramic" to designate the "technical ceramics" that can constitute component 6. By "dense", we consider a material whose density is between 95 and 100% of the theoretical density of the material considered.It should be noted that the term "based on" here means that the designated chemical component represents at least 50% by weight of the overall chemical composition of the ceramic concerned. As a note, the technical ceramic used to form the component differs a priori from the ceramic possibly used to form the mold.

[0068] In a second embodiment of the invention, the second structure 1 is intended to form, at least partially, a master 2' for a mold 3' for manufacturing a watch component 6. At the end of the second step E2, the assembly of the two photosensitive resins 31, 32 shaped respectively according to the two patterns described above forms a second structure 1 secured to the substrate 20.

[0069] THE figures 12 to 16 illustrate the successive stages of a manufacturing process for a 2' master intended to enable the manufacturing of a 3' mold of the automaton pawl represented by the Figures 1 and 2according to this second embodiment of the invention. This second structure 1 is intended here to form, in addition to the substrate 20, a master 2' for manufacturing a mold 3' of a watch component 6. Alternatively, the master 2' does not include the substrate 20 and takes the form of the second structure 1, the latter being previously separated from said substrate. Thus, unlike the first embodiment, the second structure 1 here directly forms the master 2', and not a manufacturing mold for a master.

[0070] In this second embodiment, the second structure 1 may comprise at least one cavity 13.

[0071] In this second embodiment, the method for manufacturing a watch component comprises a third step consisting of using E4', E4", E4* the master 2' to manufacture a mold 3', as illustrated by the figure 17 .

[0072] According to a first variant of the second embodiment, this mold 3' is advantageously made of a flexible material so that it can be easily removed from the master 2'. This mold 3' can, for example, be made of a polymer, in particular an elastomer such as PDMS (Polydimethylsiloxane) or silicone.

[0073] According to this first variant of the second embodiment, the method of manufacturing a watch component comprises a third step consisting of using E4' the master 2' to manufacture a mold 3' as shown in the figure 17 . Step E4' may, for example, comprise sub-steps E41', E42', E43', E44' similar to sub-steps E41, E42, E43, E44 of step E4, which have been previously described.

[0074] In second and third variants of the second embodiment, the mold 3' may be rigid. In this case, the master 2' may be sacrificial.

[0075] According to a second variant of the second embodiment, the mold 3' results from the growth of a layer of metal or a metal alloy on the substrate 20. Thus, the mold 3' is preferably made up of the substrate 20, the possible layer 21, and the layer of metal or the metal alloy having grown on said substrate. Alternatively, the mold 3' does not include the substrate 20 and takes the form of the layer of metal or the metal alloy having grown on the substrate, the latter being previously separated from said substrate. The mold 3' here comprises at least one cavity.

[0076] According to this second variant of the second embodiment, the third step consisting of using E4" the master 2' to manufacture a mold 3' comprises sub-steps E41", E42", E43" which are similar to the sub-steps E31, E32, E33 of step E3 of the first variant of the first embodiment of the invention.

[0077] According to a third variant of the second embodiment, the mold 3' results from the formation of a ceramic layer on the substrate 20. Thus, the mold 3' is preferably made up of the substrate 20, the possible layer 21, and the ceramic layer formed on said substrate. Alternatively, the mold 3' does not include the substrate 20 and takes the form of the ceramic layer on the substrate, the latter being previously separated from said substrate. The mold 3' here comprises at least one cavity.

[0078] According to this third variant of the second embodiment, the third step consisting of using E4* the master 2' to manufacture a mold 3' comprises sub-steps E41*, E42*, E43*, E44* which are similar to the sub-steps E31', E32', E33', E34' of step E3' of the second variant of the first embodiment of the invention.

[0079] Whatever the embodiment variant of the second embodiment, the method of manufacturing a watch component then comprises a fourth step consisting of manufacturing E5' a watch component 6 using the mold 3'.

[0080] Step E5' may in particular comprise sub-steps E51', E52', E53', E54' which are similar to sub-steps E51, E52, E53, E54 of step E5, which have been previously described.

[0081] In the case of a rigid 3' mold, the component 6 or the component blank 6 can be removed from the 3' mold by taking advantage of the shrinkage of the material constituting the component or the component blank 6.

[0082] The method for manufacturing a watch component previously described can be used for the manufacture of any watch components such as, by way of illustrative and non-limiting examples, a balance wheel, an anchor, a jumper, a pinion, a wheel, a lever, a spring, a balance wheel, a cam, or even a blank. It can in particular naturally be used to manufacture any element comprising a microstructure.

[0083] It therefore appears that the invention achieves the desired objects by advantageously combining two different technologies. Traditional photolithography makes it possible to form the main volume of the master intended to enable the manufacture of a watch component mold, in a simple, rapid and reliable manner by a first step, and the two-photon polymerization technology makes it possible to add complex shapes to this main volume, by a second step which is more complex and less rapid but more precise and flexible, making it possible to define any three-dimensional pattern. The result is a master for a watch component mold of complex shape, manufactured in a simple and robust manner.

Claims

1. A method for manufacturing a master pattern (2) for a mold (3) for a horology component, comprising at least the following steps: - Manufacturing (E1) a first structure (10) from a first photosensitive resin (31) comprising at least one layer of photosensitive resin comprising a first pattern obtained by polymerizing the first photosensitive resin by irradiation through at least one mask (4), then developing said first photosensitive resin; - Transforming (E2) the first structure (10) into a second structure (1) by structuring at least one surface (11) of the first structure by the addition of a second photosensitive resin (32) to said at least one surface, this step consisting in transforming (E2) the first structure comprising the following steps: ∘ Applying (E21) a layer of the second photosensitive resin (32) on at least part of the at least one surface (11) of the first structure; ∘ Performing two-photon polymerization (E22) on the second photosensitive resin (32) in order to obtain three-dimensional polymerization according to the second pattern, using a photon device which comprises an objective (51) which is at least partially immersed in the second resin to direct and focus a beam (52) on voxels that define the shape and / or the geometry of the second pattern; ∘ Developing (E23) in order to eliminate the non-polymerized second photosensitive resin (32) and obtain the second structure (1) of a form defined by the first and second patterns, wherein in said method the the second structure (1) directly forms the master pattern (2) of a mold (3) for a horology component or forms a mold (3) for the manufacture by molding of a master pattern (2) of a mold (3) for a horology component.

2. The method for manufacturing a master pattern (2) for a mold (3) for a horology component as claimed in the preceding claim, characterized in that the step consisting in transforming (E2) the first structure (10) comprises the addition of the second photosensitive resin (32) on at least one lateral surface (11) of the first structure.

3. The method for manufacturing a master pattern (2) for a mold (3) for a horology component as claimed in one of the preceding claims, characterized in that the step consisting in transforming (E2) the first structure comprises the application (E21) of the second photosensitive resin (32) on said at least one surface (11), the three-dimensional polymerization (E22) of this second resin according to a second pattern, and the developing (E23) of the second resin.

4. The method for manufacturing a master pattern (2) for a mold (3) for a horology component as claimed in one of claims 1 to 3, characterized in that the step that consists in performing two-photon polymerization (E22) makes it possible to define a second pattern with a three-dimensional resolution better than or equal to 0.001 µm3 and / or with a lateral resolution better than or equal to 0.1 µm.

5. The method for manufacturing a master pattern for a mold for a horology component as claimed in the preceding claim, characterized in that the step consisting in exposing (E12) the first resin (31) generates a first structure (10) comprising lateral flanks perpendicular or substantially perpendicular to the substrate (20) and / or a constant cross section parallel or substantially parallel to the substrate (20).

6. The method for manufacturing a master pattern (2) for a mold (3) for a horology component as claimed in one of the preceding claims, characterized in that: - The two resins (31, 32) are identical or different; and / or - The two resins (31, 32) are positive or negative; and / or - The first resin (31) is of SU-8 type or of SU-8-100 type; and / or - The second resin (32) is a liquid or semiliquid resin, notably IP-Dip™.

7. The method for manufacturing a master pattern (2) for a mold (3) for a horology component as claimed in one of the preceding claims, characterized in that it comprises the following steps: - Using electrodeposition or electroplating to apply (E31) to the second structure (1) a layer of metal (22) that at least partially forms the master pattern for the mold for the horology component; - Separating (E33) from said second structure the master pattern for the mold for the horology component which is formed by said layer of metal.

8. The method for manufacturing a master pattern (2) for a mold (3) for a horology component as claimed in the preceding claim, characterized in that the metal (22) is nickel-based or is a nickel-phosphorus alloy.

9. The method for manufacturing a master pattern (2) for a mold (3) for a horology component as claimed in one of claims 1 to 6, characterized in that said method comprises the following steps: - Using a liquid route to fill (E31') the second structure (1) with a product containing ceramic powder; - Consolidating (E32') said product; - Separating (E33') from said second structure (1) the blank formed by said product; - Debinding the blank obtained in the preceding step, then densifying it (E34') by sintering.

10. A method for manufacturing a horology component (6), characterized in that it comprises a step consisting in manufacturing a master pattern (2; 2') using a method as claimed in one of the preceding claims, a step consisting in using this master pattern to manufacture (E4; E4'; E4"; E4*) a mold (3; 3') for manufacturing a horology component, and then a step consisting in using said mold (3; 3') as a manufacturing mold to manufacture (E5; E5') the horology component, it being possible for the latter to be made of ceramic, notably of technical ceramic.

11. The method for manufacturing a horology component (6) as claimed in the preceding claim, characterized in that the mold (3; 3') is manufactured from a polymer, notably from an elastomer such as PDMS (polydimethylsiloxane) or silicone.

12. The method for manufacturing a horology component (6) as claimed in the preceding claim, characterized in that the step consisting in using this master pattern to manufacture (E4; E4') a mold (3; 3') comprises the following substeps: - circumscribing (E41; E41'), with an annular element (7), a volume intended to receive a volume of polymer, to complement the master pattern (2; 2'); - pouring (E42; E42') a volume of elastomer into the impression cavity formed by the master pattern (2; 2') completed by the annular element (7); - polymerizing (E43; E43') the volume of elastomer so as to solidify it; - separating (E44; E44') the elastomer mold (3; 3') from the master pattern (2; 2') and from the annular element (7).

13. The method for manufacturing a horology component (6) as claimed in claim 10, characterized in that the mold (3; 3') is manufactured in metal or in metal alloy or in ceramic.

14. The method for manufacturing a horology component (6) as claimed in one of claims 10 to 13, characterized in that the step consisting in manufacturing (E5; E5') the horology component comprises manufacturing it in technical ceramic using the following substeps: - using a liquid route to fill (E51; E51') the mold (3; 3') with a product containing ceramic powder; - consolidating (E52; E52') said product; - separating (E53; E53') the blank formed by said product from the manufacturing mold (3; 3'); - debinding the blank obtained in the preceding substep, then densifying it (E54; E54') by sintering.