Method for manufacturing a timepiece component

Abstract

Disclosed is a method for manufacturing a mould for manufacturing a timepiece component, the method being characterised in that it comprises the following steps: - depositing (E1.2) a layer N (30) of photoresist resin; - exposing (E1.3) the photoresist resin of the layer N (30) of photoresist resin to exposure radiation (55) according to a first predefined pattern, thereby defining at least one portion (32) of the unexposed photoresist resin of the layer N (30); - depositing (E1.c) a conductive layer (36) directly on all or part of the surface of the layer N (30) of exposed photoresist resin; - depositing (E1.4) an optical filter layer (35) directly at least on all or part of the conductive layer (36) and / or its flanks; - depositing (E1.5) a layer N+1 (40) of photoresist resin directly and / or indirectly on the photoresist resin of the layer N (30), in particular on the conductive layer (36) and / or on the optical filter layer (35).

Description

[0001] Manufacturing process of a watch component

[0002] The present invention relates to a method of manufacturing a mold for manufacturing a watch component. It also relates to a method of manufacturing a watch component which uses such a mold. It also relates to a mold for manufacturing a watch component as such, obtained by such a method.

[0003] Existing manufacturing processes for watch components are poorly or not at all suitable for the manufacture of a component with a complex geometry, i.e., in particular one with a complex three-dimensional shape. These processes sometimes manage to achieve certain complex geometries, but through tedious steps such as post-machining, and / or to the detriment of the resolution of the geometry, which leads to a lack of precision in the shapes obtained. Generally speaking, existing manufacturing processes for watch components therefore do not allow all complex shapes to be manufactured with sufficient precision.

[0004] Thus, the object of the present invention is to improve the known methods of manufacturing a watch component, and in particular to be able to manufacture a watch component of complex shape in a simple manner and with great precision.

[0005] To this end, the invention is based on a method of manufacturing a mold for the manufacture of a watch component, characterized in that it comprises the following steps:

[0006] Deposit an N layer of photosensitive resin;

[0007] Insolating said photosensitive resin of the N layer of photosensitive resin with insolation radiation according to a first predefined pattern, defining at least a portion of photosensitive resin of the non-insulated N layer; Depositing a conductive layer directly on all or part of the surface of the N layer of insolated photosensitive resin;

[0008] Depositing a layer of optical filter directly at least on all or part of the conductive layer and / or its sides;

[0009] Deposit an N+1 layer of photosensitive resin directly and / or indirectly on the N layer of photosensitive resin, in particular on the conductive layer and / or on said optical filter layer.

[0010] The invention also relates to a method of manufacturing a watch component, characterized in that it comprises a first step corresponding to the method of manufacturing a mold as described above, and a second step of forming the watch component comprising a step of filling all or part of said mold with a material of the component.

[0011] The invention also relates to a mold for manufacturing a watch component, characterized in that it comprises a layer N of photosensitive resin forming at least a first cavity of the mold and a layer N+1 of photosensitive resin forming at least a second cavity of the mold, this second cavity being superimposed on the first cavity and of larger surface area than the first cavity so that an upper surface of the layer N of photosensitive resin is located directly inside the second cavity of the layer N+1 of photosensitive resin, in that this upper surface of the layer N of photosensitive resin which is located in the second cavity is covered by a conductive layer which forms a bottom of the second cavity, and in that an optical filter layer is in contact with a side of the conductive layer and is positioned at least partly between the two layers N, N+1 of photosensitive resin.

[0012] The invention is more particularly defined by the claims. These objects, characteristics and advantages of the present invention will be explained in detail in the following description of a particular embodiment made without limitation in relation to the attached figures among which:

[0013] Figures 1 to 3 represent sectional views of a mold during the sub-steps of a method of manufacturing this mold for a watch component according to a first variant of an embodiment of the invention.

[0014] Figure 4 represents a sectional view of the mold for a watch component obtained according to the first variant of the embodiment of the invention.

[0015] Figure 5 represents a sectional view of a mold during a sub-step of a method of manufacturing this mold for a watch component according to a second variant of the embodiment of the invention.

[0016] Figure 6 represents a sectional view of the mold for a watch component obtained according to the second variant of the embodiment of the invention.

[0017] Figure 7 schematically represents the sub-steps of the method of manufacturing a mold for a watch component according to the embodiment of the invention.

[0018] Figure 8 illustrates a step of filling a mold during the manufacture of a watch component according to the state of the art.

[0019] Figure 9 schematically illustrates the sub-steps of the method of manufacturing a watch component from a mold according to the invention.

[0020] The invention achieves the desired objects by the intermediate manufacture of a particular mold, which may have a complex shape, in order to obtain a watch component of complex shape by a simple molding in this particular mold. A complex shape is notably achieved by the use of a multi-level mold, that is to say, one in the form of a structure formed by several layers superimposed in a certain stacking direction, each layer forming a part of the mold cavity. By convention, we will consider the adjectives "upper" and "lower" in relation to this stacking direction, the first positioned elements being lower and below the elements subsequently deposited above, which will be higher than them.

[0021] The invention first relates to a method of manufacturing a mold for manufacturing a watch component, as shown schematically in Figures 1 to 6. It then relates to a method of manufacturing a watch component as such, the first step E1 of which consists of implementing said method of manufacturing a mold, and the second step E2 of which consists of using such a mold to manufacture a watch component as such.

[0022] For ease of reading, the same references will be used for the different embodiments and the different variants of the invention to designate identical or very similar characteristics.

[0023] We will first describe the method of manufacturing a mold for the manufacture of a watch component according to particular embodiments chosen as illustrative examples. This method therefore forms a first step E1 before the subsequent manufacture of a watch component, and we will describe below the sub-steps of this first step E1.

[0024] Figures 1 to 4 represent a first variant of an embodiment of the invention.

[0025] The method comprises a first sub-step E1.1 consisting of providing a substrate 20 which is in a substantially flat shape of small thickness, comprising an upper surface 21. The substrate 20 may be in the form of a wafer. This substrate 20 may be in an electrically conductive material, such as a metal or a metal alloy, such as stainless steel. Alternatively, it may be in a semiconductor material, such as silicon, or in a non-conductive material, for example ceramic. In the latter cases, it may be advantageous to coat the upper surface 21 with a conductive layer, for example by thermal evaporation; this conductive layer may optionally be in the form of a multilayer structure, for example an underlayer of chromium, nickel or titanium covered with a layer of gold or copper.The function of such a conductive property of the upper surface 21 of the substrate 20 is to be able to participate in the initiation of a mold filling process by electroforming for example, as will be detailed later.

[0026] The upper surface 21 of the substrate 20 is generally flat, and may be polished, or alternatively may comprise positive or negative relief patterns, in particular machined patterns, and / or cavities, and / or other structures, for example produced by microfabrication. The substrate 20 may be provided with markers, so that it can be positioned very precisely during the various steps. It may be prepared in any known manner, in particular for its degreasing, its cleaning, possibly its passivation and / or its activation.

[0027] In all cases, the substrate 20 fulfills the function of support for the manufacture of the mold which will be formed by a stack of several layers of photosensitive resin superimposed on the upper surface 21 of the substrate, according to the photolithography technology, an integral part of the LIGA process (abbreviation for "Lithography, Galvanoformung, Abformung"). The substrate 20 is thus covered with several layers of photosensitive resin, each layer being intended to ultimately form a part of the mold.

[0028] The invention will be illustrated on the basis of two superimposed photosensitive resin layers, which can be integrated into a structure comprising a multitude of layers: for this reason, these layers will be called N and N+1 layers. To simplify the figures, only these two N, N+1 layers will be shown, and positioned directly on the substrate. Naturally, the invention is not limited to a mold formed by only two photosensitive resin layers, but applies to any number of layers greater than or equal to two. Moreover, the concept of the invention can be implemented on any pair of successive resin layers, and on any number of pairs of successive resin layers among all the superimposed layers. In other words, the concept of the invention can be implemented at least at any two successive N, N+1 resin layers, and at most at all pairs of two successive resin layers.

[0029] The method comprises a second method substep consisting of depositing E1.2 a layer N 30 of photosensitive resin on the surface 21 of the substrate 20, or alternatively on another layer N-1, as explained previously. The resin is deposited according to known methods. The resin used can be deposited in liquid phase, or alternatively, in solid phase: it is then called “dry” resin. In the case of a liquid resin, the deposition can for example be carried out by “spin-coating” (also called “rotational deposition” or “centrifugal coating” or “centrifugal coating”) or by “spray-coating” (also called “spray deposition” or “spray coating”). In the case of a dry resin, the deposition can for example be carried out by a rolling or pressing process.

[0030] Figure 1 represents a third sub-step of the process consisting of exposing E1.3 said photosensitive resin of the N layer 30. Indeed, the photosensitive resin is suitable for photolithography. This resin can be negative or positive. In the first case of a negative resin, it is designed to become insoluble or difficult to dissolve in a developer under the action of exposure radiation, that is to say that the areas exposed to a certain so-called exposure radiation will resist development, as will be detailed later. In the second case of a positive resin, the resin is on the contrary designed to become soluble in a developer under the action of exposure radiation, while the part not exposed to the radiation remains insoluble or difficult to dissolve.In all the examples and illustrations that follow, the resin used is of the “SU-8” type, and is a negative photosensitive resin, which polymerizes under the action of UV (ultraviolet) radiation, such as for example the SU-8-100 resin from the company Kayaku Advanced Materials. In all the embodiments, this negative resin could be replaced by a positive resin, and the insolation radiation, the masks, and the different layers of the stack will then be adapted to this type of resin.

[0031] As shown in Figure 1, the N layer 30 of photosensitive resin is subjected to insolation radiation 60 through a mask 50, comprising openings 51 allowing the insolation radiation 60 to pass through, which thus reaches parts 31 of the N layer 30 of photosensitive resin. The mask 50 further comprises at least one opaque zone 52 to the insolation radiation, which does not allow the insolation radiation 60 to pass through. The mask 50 corresponds to a first predefined pattern, and defines at least one part 32 of non-insolated photosensitive resin. As a note, to obtain an equivalent result with a positive resin, the mask used would be reversed, so that the part(s) 31 insolated with a negative resin would not be insolated with a positive resin, while the part(s) 32 not insolated with a negative resin would be insolated with a positive resin. At the end of this insolation sub-step E1.3, the layer N 30 of photosensitive resin is said to be “exposed”, and therefore comprises one or more exposed parts 31 and one or more non-exposed parts 32. As a remark, the exposed layer according to the invention therefore corresponds to a layer of resin comprising exposed resin and non-exposed resin.

[0032] In the embodiment illustrated by FIG. 1, the mask 50 extends in a plane parallel to the surface 21 of the substrate 20, and the insolation radiation 60 is perpendicular to the plane in which the mask 50 extends, so as to irradiate only the parts 31 of the photosensitive resin located at right angles to the openings 51 formed in the mask. Alternatively, the insolation radiation could be inclined relative to the plane in which the mask extends and / or that of the upper surface 21 of the substrate 20. As a further variant, not illustrated, a mask with varying transmittance can also be used so as to form inclined sides in the resin, or even a surface structuring of the different levels of resin.

[0033] The insolation radiation 60 used to irradiate or insolate the photosensitive resin is UV radiation in the case of SU-8 resin. X-rays, electrons, or any other type of insolation radiation suitable depending on the resin used can be used. In addition, this insolation sub-step E1.3 optionally includes a sub-step of heat treatment for crosslinking the resin.

[0034] The method then comprises a sub-step consisting of depositing E1.c a conductive layer 36, directly on all or part of the upper surface of the N layer 30 of insolated photosensitive resin. As will be detailed later, it is advantageous to form a mold which comprises conductive surfaces, in particular for its subsequent filling by electroplating, according to LIGA technology. According to this embodiment, the deposition of the conductive layer 36 is carried out by physical vapor deposition (PVD). This conductive layer 36 may be made of a metal, or a metal alloy. Advantageously, it may be gold.

[0035] Furthermore, according to this first variant of the embodiment, the conductive layer 36 is deposited over the entire surface of the N layer 30 of photosensitive resin. This approach is advantageous because it is simple to implement. Alternatively, it may only be deposited on certain specific parts of the N layer, as will be illustrated in the second variant embodiment in relation to FIGS. 5 and 6.

[0036] The method for manufacturing a mold then comprises a sub-step consisting of depositing E1.4 an optical filter layer 35, at least on all or part of the conductive layer 36, and preferably at least on the entire conductive layer 36. According to this first variant of the embodiment, this optical filter layer 35 is deposited on the entire surface of the layer N 30 of photosensitive resin, indirectly since it is superimposed on the conductive layer 36 over its entire surface.

[0037] The optical filter layer 35 fulfills a function of protecting the N+1 layer 40 of photosensitive resin, to prevent its parasitic insolation, as will be detailed later. For this, the optical filter layer 35 fulfills the optical function of filtering the wavelengths which insolate the photosensitive resin of the N+1 layer. It thus prevents any parasitic insolation of the photosensitive resin, which would involuntarily modify the insolation defined by the sub-step E1.6, which will be described below, and which would ultimately induce a modification of the precision of the geometry of the mold during manufacture. Preferably, the optical filter layer 35 makes it possible to attenuate more than 98%, or even more than 99%, or even more than 99.9% of such insolation radiation.

[0038] The optical filter layer may be an antireflective layer and / or an absorbing layer. It may be deposited by various methods, for example spin-coating (also called spin-coating), spray-coating (also called spray-coating), dip-coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), pulsed laser ablation deposition (PLD), or by rolling or pressing processes. It may comprise a material of an organic nature. In particular, it may be a layer of the material known by its trade name AZ®-BARLi® II.

[0039] Advantageously, the optical filter layer 35 is entirely deposited in the same plane. Here, it is a plane parallel to the plane of the upper surface 21 of the substrate 20. It is deposited, directly or indirectly according to this first variant, on the layer N 30 of undeveloped photosensitive resin. Figure 2 represents the structure obtained after carrying out sub-steps E1.4 and E1.c.

[0040] The method then implements a sub-step consisting of depositing E1.5 a layer N+1 40 of photosensitive resin on the layer N. In this embodiment, this deposition is indirect on the layer N since the two layers N, N+1 are separated by the optical filter layer 35 and the conductive layer 36, which extend over the entire upper surface of the layer N. This deposition of photosensitive resin of the layer N+1 is carried out by any known method, in particular the methods mentioned above for the deposition of the layer N.

[0041] The method then implements a sub-step consisting of exposing E1.6 the photosensitive resin of the N+1 layer, as represented by FIG. 3. The N+1 layer 40 of photosensitive resin is subjected to exposure radiation 65 through a mask 55, comprising openings 56 allowing the exposure radiation 65 to pass through, which thus reaches parts 41 of the N+1 layer 40 of photosensitive resin. The mask 55 further comprises opaque zones 57 to the exposure radiation which do not allow the radiation to pass through. The mask 55 corresponds to a second predefined pattern, and defines at least one part 42 of non-exposed photosensitive resin. At the end of this exposure sub-step E1.6, the N+1 layer 40 of photosensitive resin is said to be “exposed”, and therefore comprises one or more parts 41 of exposed resin and one or more parts 42 of non-exposed resin. These two sub-steps E1.5 and E1.6 are very similar to the sub-steps E1.2 and E1.3 relating to the N layer.

[0042] In this exposure sub-step E1.6, the optical filter layer 35 fulfills a function of protecting the N+1 layer 40 of photosensitive resin, to prevent its parasitic exposure. Indeed, during this step, the exposure radiation 65 intended for the exposure of the N+1 layer 40 would risk being reflected on the conductive layer 36 and reaching parts 42 of resin of the N+1 layer 40 which should not be exposed. The existence of parasitic exposure radiation is relatively predictable since it depends on the geometry of the chosen configuration. Thus, preferably, as soon as there is a risk of parasitic exposure radiation, the method according to the invention is implemented, as described previously, to thereby eliminate in whole or in part the occurrence of such parasitic exposure radiation, and thus guarantee the precise formation of a mold.It appears that a risk of stray insolation exists even in a simple situation of insolation radiation perpendicular to the substrate, and with superimposed layers of resin comprising upper and / or lower surfaces parallel to the substrate, i.e. in a priori simple angular geometries. Indeed, as described previously, despite this approach, the sheer complexity of the geometry of the different superimposed layers, due to the relative positioning of their insolated and non-insolated parts, and due to the presence of a conductive layer, can induce risks of stray insolation.

[0043] As a note, in all the exposure steps of all the embodiments of this invention, or even more generally in any solution requiring exposure of a resin, an optical filter layer may be arranged on the resin layer to fulfill the function of a mask during exposure, replacing a traditional mask. Thus, an invention may relate to any method comprising a step of exposure of a resin layer in which an optical filter layer is arranged on said resin layer to fulfill the function of a mask. The optical filter layer having served as a mask may then be retained or may be removed.

[0044] As a note, the second pattern defined by the mask 55 applied to the N+1 layer is consistent with the first pattern defined by the mask 50 applied to the N layer, so as to obtain at least partially superimposed insolated and / or non-insolated parts, to finally form a mold. Indeed, the method then implements a sub-step consisting of developing E1.7.1, E1.7.2 the photosensitive resin of the N and N+1 layers. In this sub-step, a portion of resin is dissolved to form a cavity in each resin layer, a cavity of each level being at least partially superimposed on a cavity of the following level, so as to reveal the structure of the mold. In the case of the embodiment where the photosensitive resin is negative, the development consists of eliminating (i.e. deleting, etching, removing) the non-insolated resin parts 32, 42. Alternatively, if the photosensitive resin is positive, the development consists of eliminating the insolated resin areas.

[0045] The development method is known to those skilled in the art and is adapted to the resin used. It can be done by dissolving the resin chemically, using suitable solvents and being carried out by spraying solvents or by immersion in them. Alternatively, the development can use a plasma process. A specific feature of this embodiment comes from the fact that the development acts through the conductive layer 36 and the optical filter layer 35 to allow the development of the N layer 30 of photosensitive resin on which these layers 35, 36 are deposited.

[0046] In the case of development by chemical dissolution of the resin, the method of applying the solvents by spraying can have sufficient mechanical action on the structure of the layers 35, 36 to damage them so that the solvents can reach the photosensitive resin of the N layer 30 on which they are deposited. The method of applying the solvents by immersion is nevertheless preferred from an industrial point of view due to its simplicity of implementation. Immersion alone may prove insufficient for the passage of the solvents through the intermediate layers, which would then be removed by lifting (or "lift-off"). Alternatively, a conventional photolithography step followed by etching can be implemented to make openings in the layers 35, 36 and thus facilitate the passage of the solvents to the lower N layer 30.As a further variant, during immersion in the solvents, ultrasound is applied to break the layers 35, 36 and facilitate access of the solvents to the photosensitive resin of the lower N layer. As a further variant, the same effect could be obtained by stirring the baths or by using megasounds. This solution therefore makes it possible to implement the development of the two superimposed layers N, N+1 of photosensitive resin, whether they are immediately juxtaposed (in direct contact), or separated by the intermediate layers 35, 36. In addition, this development is simultaneous for the two layers N, N+1, i.e. is carried out in the same resin dissolution operation.This development can therefore be done chemically by immersion, which is industrially favorable, while optimizing the yield thanks to the variants of assistance by ultrasound (according to a broad definition, i.e. a pressure wave of frequency equal to or greater than 20 kHz, and less than or equal to 200 kHz) and others mentioned above.

[0047] Figure 4 illustrates the resulting multi-level resin mold 10 after development. The locations where the photosensitive resin has been dissolved constitute the mold cavity. This mold cavity is thus formed by a first cavity 11 corresponding to the non-exposed portion(s) 32 of the N layer 30, and by a second superimposed cavity 12 corresponding to the non-exposed portion(s) 42 of the N+1 layer 40. These cavities 11, 12 are further delimited respectively by flanks 13, 14 which are perpendicular to the upper surface 21 of the substrate 20 and free of conductive layer. The upper surface 21 of the substrate forms a part of the bottom of the mold.Furthermore, in the embodiment shown, the cavity 12 formed in the upper N+1 layer has a surface area greater than that of the cavity 11 formed in the lower N layer, revealing upper surfaces of the N layer 30, parallel to the upper surface of the substrate, which form bottoms of the mold at the level of the cavity 12 of the N+1 layer 40. In other words, said two predefined patterns are such that the development of said two layers N, N+1 30, 40 of photosensitive resin forms at least one first cavity 11 of the resin layer N 30 and at least one second cavity 12 in the N+1 layer 40 of photosensitive resin, this second cavity 12 being superimposed on the first cavity and of larger surface area than the first cavity 11 so that an upper surface of the N layer 30 of photosensitive resin is located directly inside the second cavity 12 of the N+1 layer 40 of photosensitive resin.In this embodiment, the method comprises a complementary sub-step of removing the optical filter layer 35 at these upper surfaces of the N layer 30 which are located in the cavity 12. This removal can be done by etching. Thus, these surfaces are finally covered with a conductive layer 36 which will fulfill an important function during the filling of the mold, as will be detailed later.

[0048] According to the embodiment, the conductive layer 36 and the optical filter layer 35 are deposited on the entire upper surface of the N layer of photosensitive resin. This approach is advantageous because it is simple to implement. Alternatively, the conductive layer may only be deposited on certain parts of the N layer, in particular at the resin zones of the N+1 layer intended to be removed during the development sub-step. In this case, it may be locally etched, to remove a part of the conductive layer 36 previously added over the entire surface of the N layer. Alternatively, the conductive layer 36 may be deposited selectively. To carry out these so-called selective deposits, one possibility is to proceed with a masking protecting by a sacrificial layer the locations of the N layer not to be coated.In all these cases, the optical filter layer 35 is adapted to the distribution of the conductive layer, to best fulfill its function of protection against parasitic reflections. It may thus not extend over the entire surface of the N layer 30 of photosensitive resin.

[0049] Figure 5 illustrates a mold 10 during manufacture, during the sub-step consisting of exposing E1.6 the photosensitive resin of the N+1 layer according to a second embodiment variant, which differs in that the conductive layer 36 and the optical filter layer 35 do not extend over the entire surface of the N layer 30 of photosensitive resin. They may extend below the parts 42 of photosensitive resin of the N+1 layer 40 of photosensitive resin intended not to be exposed, at least to form a background at the level of the N layer of photosensitive resin for the cavity 12 formed in the N+1 layer of photosensitive resin, the function of which will be specified later. To carry out these so-called selective deposits, one possibility is to proceed with a masking protecting by a sacrificial layer the locations of the N layer not to be coated.In this embodiment variant, the N+1 layer 40 of photosensitive resin is formed by depositing resin partly on the optical filter layer 35 and partly directly on the photosensitive resin of the N layer 30 of photosensitive resin, in the parts where the optical filter layer 35 and the conductive layer 36 are not applied. As a further remark, to obtain a maximum effect of the optical filter layer 35, the latter is deposited on the entire upper surface of the conductive layer 36, as well as on its lateral flanks, so that it comes to rest directly in contact with the N layer 30 of photosensitive resin at the flanks of the conductive layer 36. Thus, no surface of the conductive layer 36 is likely to reflect part of the insolation radiation 65, the conductive layer 36 is completely encapsulated by the optical filter layer 35.As a note, the optical filter layer thus advantageously comprises a main portion parallel to the upper surface of the substrate, preferably flat. It further comprises, optionally, a portion perpendicular to the upper surface of the substrate, at the level of the sides of the conductive layer.

[0050] Figure 6 illustrates the mold 10 according to this second embodiment variant, which differs from the mold of the first variant shown in Figure 4 by the fact that the conductive layer 36 does not extend over the entire surface of the N layer 30 of photosensitive resin, but advantageously to form a bottom at the level of the N layer for the cavity 12 formed in the N+1 layer of photosensitive resin, the function of which will be specified later. As a remark, this result is achieved after a prior complementary sub-step of removing the optical filter layer 35 superimposed on the conductive layer, at the level of these upper surfaces of the N layer 30 which are located in the cavity 12. Thus, only a small proportion of the optical filter layer remains, that which was positioned against the side of the conductive layer. Naturally, the invention is not limited to the embodiment variants described above.Many mold geometries are possible, depending on the watch component to be manufactured.

[0051] In particular, the conductive layer 36 may extend over the N layer in any other pattern than the embodiments described, even if some patterns will be less efficient than others. The optical filter layer 35 may likewise extend in a different manner, at least in part over the conductive layer 36. However, it may not entirely cover the conductive layer 36. The conductive layer 36 and / or the optical filter layer 35 may be in several distinct and possibly superimposed or even juxtaposed layers.

[0052] Unlike the variants described previously, the two layers N, N+1 of photosensitive resin could be developed in two separate sub-steps E1.7.1, E1.7.2, the layer N 30 of photosensitive resin being exposed and developed before the deposition of the layer N+1 40 of photosensitive resin. More precisely, the layer N 30 can thus be developed after the sub-step consisting of depositing E1 c the conductive layer 36 and after, or even before the sub-step consisting of depositing E1 .4 the optical filter layer 35.

[0053] Figure 7 schematically summarizes the sub-steps of the method for manufacturing a mold according to the embodiment of the invention. We can note that there is an optional sub-step E1.7.1 of development of the N layer of photosensitive resin, before the deposition of the N+1 layer, corresponding to a certain embodiment variant. This optional step is represented by a dotted line.

[0054] In all embodiments and their variants, the development sub-step is adapted to the resin used, and may be based on a dissolution of the resin by chemical means, using appropriate solvents and being implemented by spraying solvents or by immersion in them, in a manner known to those skilled in the art. However, the presence of an intermediate zone between two layers N, N+1, or at least on the N layer, or even on the N+1 layer, to be developed in the same operation, or not, by the same chemical means, complicates access to the N layer located under the intermediate zone, or even to the N+1 layer if it is located under an optical filter type layer. In other words, this intermediate zone forms a barrier for the passage of the chemical solution to the resin layer that it covers.Thus, to assist this sub-stage of development, in all embodiments and their variants, ultrasound can be applied to break the intermediate layers and facilitate access of the solvents to the photosensitive resin of the lower N layer, or even to access the N+1 layer. We understand ultrasound to be a broad definition, i.e. a pressure wave with a frequency equal to or greater than 20 kHz, and less than or equal to 200 kHz. As a variant or complement, the agitation of the baths or the use of megasounds could be implemented. This solution therefore makes it possible to implement the development of the two superimposed N, N+1 layers of photosensitive resin, or at least of the lower N layer, or even of the N+1 layer. This development can therefore be done chemically by immersion, which is industrially favorable, while optimizing the yield thanks to the ultrasonic assistance variants and others mentioned above.

[0055] It therefore appears in the preceding embodiments that a combination of a conductive layer and an optical filter layer is particularly suitable for many molds for manufacturing watch components, as will be specified later.

[0056] As explained above, the embodiment of the invention has been presented on the basis of a two-layer resin mold, in a simplified manner. Naturally, the principle of the invention can be applied to form any structure with several resin layers, the number of which can be greater than two. In addition, the intermediate layer(s), consisting of one or more optical filter layers and / or one or more conductive layers, can have different configurations.The invention also relates to a mold for manufacturing a watch component as such, characterized in that it comprises a layer N of photosensitive resin forming at least a first cavity of the mold and a layer N+1 of photosensitive resin forming at least a second cavity of the mold, this second cavity being superimposed on the first cavity, the upper surface of the layer N of photosensitive resin being at least partially covered by a conductive layer, and an optical filter layer extending at least partly between the two layers N, N+1, 30, 40 of photosensitive resin.

[0057] The invention also relates to a method for manufacturing a watch component as such, the first step E1 of which consists of implementing the method for manufacturing a mold as described above. Such a type of mold is multi-layer, as described above. Each layer comprises one or more cavities, and the joining of these cavities, which communicate with each other, forms a larger cavity, the mold cavity, the overall geometry of which corresponds to that of the watch component to be manufactured. The second step E2 of the manufacturing method is based on the use of such a mold to manufacture a watch component 1 as such.

[0058] An embodiment of this second step E2 will now be described in detail. The second step E2 comprises a first substep consisting of filling E2.1 all or part of the mold with a material 2, which we will call the component material.

[0059] According to a first embodiment variant, this sub-step consists of filling E2.1 the mold by electrodeposition, electroforming, or electroplating. It then makes it possible to produce a metal component. The material 2 of the component can then be a metal or a metal alloy such as, for example, gold, nickel, copper, or nickel-phosphorus (NiP). This sub-step is preferably extended until the entire height of the mold cavity is filled, which has the advantage of allowing the continuous growth of a metal or an alloy, in the same filling operation.

[0060] In this first embodiment variant, it is necessary for the mold to be at least partly made of conductive material, to act as an electrode for priming, with a view to future metallic growth of the watch component in the mold. Thus, if the substrate is not made of conductive material, such a conductive layer is added to the substrate in the first step of manufacturing the mold, as described previously, in the case where a part of the upper surface 21 of the substrate 20 forms a bottom of the mold.

[0061] On the other hand, at least one conductive layer 36 is advantageously used, as previously described in the manufacture of the mold, to likewise fulfill an electrical conductor function during the growth of the metal in such a mold. As a remark, the presence of such a conductive layer 36 fulfills an important function in certain mold geometries. As an example, Figure 8 illustrates a phenomenon observed by the filling of a mold of a certain configuration comprising an enlarged cavity 12 positioned above a narrower cavity 11. Imperfect filling occurs in the state of the art, forming a so-called mushroom-shaped defect 5 due to a growth front that does not remain horizontal.Such an untimely phenomenon is eliminated by the geometry of the mold formed by the invention, in particular that represented by the first embodiment and represented by FIGS. 4 and 6, due to the presence of the conductive layer 36 at the bottom of the cavity 12 of the N+1 layer 40, at the level of the upper surface of the N layer 30. As a remark, if such a conductive layer 36 were also present on a flank 13 of the narrow cavity 11 of the N layer, then the presence of another type of filling defect (porosity) would also be observed; if such a conductive layer 36 were present on a flank 14 of the cavity 12 of the N layer, then the presence of a defect would also be observed. Consequently, it is important to deposit the conductive layer 36 according to the invention only on the plane parallel to the substrate 20 on the N layer 30.

[0062] Optionally, an insert can be placed in the mold cavity, so that it is surrounded by the component material when filling the mold.

[0063] Step E2 then includes an optional sub-step E2.2 of thicknessing the watch component, for example by simultaneous mechanical polishing of the metal layer resulting from the galvanic growth, or more generally of the filling material, and of the resin mold, to obtain a flat, horizontal upper surface.

[0064] The method then comprises a sub-step consisting of detaching (in other words unmolding) the watch component 1 from the mold obtained by the previous step.

[0065] For this, the method comprises for example a sub-step E2.3 consisting of detaching the watch component and the resin from the mold of the substrate 20, for example by delamination of the conductive layer which coats the substrate.

[0066] The method comprises another sub-step consisting of detaching E2.4 the watch component from its resin mold. In this sub-step, the resin forming all or part of the mold is dissolved. This dissolution can be carried out by any means known to those skilled in the art, such as chemical dissolution, the use of the DRIE reactive ion etching technique, plasma etching, or laser ablation.

[0067] The order of sub-steps E2.3 and E2.4 can be reversed.

[0068] It is clear from the method described above that the entire surface of the watch component formed in direct contact with the mold according to the invention has a perfect final shape upon demolding, without the need for any additional operation. The invention thus makes it possible to very simply manufacture a watch component comprising a complex shape.

[0069] Optionally, a finishing step may be implemented on the face opposite the bottom of the mold, which is not formed directly by the mold obtained by the method according to the invention. This finishing step may consist of polishing or grinding this opposite face of the watch component, for example to ensure its flatness. In addition or as a variant, this finishing step may consist of modifying the color or the tribological properties of at least a portion of the surface of the watch component by depositing a coating formed by a physical vapor deposition (PVD), or chemical vapor deposition (CVD), or atomic layer deposition (ALD), or pulsed laser ablation deposition (PLD) process. As a note, this finishing step, which may consist of coating and / or decorating and / or machining and / or coloring and / or polishing and / or grinding, may be applied to the opposite face of the watch component not directly in contact with the mold.In this case, it can therefore be carried out before or after sub-steps E2.3, E2.4 consisting of detaching the watch component from the mold. Alternatively, the finishing step, particularly a coloring step, can be applied to the face of the watch component formed directly in contact with the mold, or even to the entire watch component.

[0070] Figure 9 schematically summarizes the sub-steps of step E2 of the manufacturing process of a watch component.

[0071] According to one embodiment, the material of the watch component is a metal or a metal alloy, in particular based on nickel or gold or copper. The resulting watch component is thus mainly made of metal or a metal alloy, for example based on nickel or gold or copper.

[0072] The method for manufacturing a watch component as described above is suitable for the manufacture of a multitude of different watch components. For example, the watch component may be a watch exterior component such as an applique or a hand, or a movement component, such as an escape wheel or an anchor or even a spring.

[0073] According to an alternative embodiment, the watch component may comprise one or more inserts, aesthetic or functional. For this, the manufacturing method may comprise an intermediate step consisting of placing at least one insert in the manufacturing mold, before the step of filling the mold with the material of the component, involving the securing of this material of the component with the at least one insert. Such an insert may be, in a non-limiting manner, a decorative precious stone, a watch axis, or a watch ruby.

[0074] In particular, the invention makes it possible to manufacture a watch component which is characterized by the fact that it is mainly in a single-piece form, and even in a single piece, since the watch component can be formed by filling the mold in a single operation of filling the entire mold, unlike, for example, a solution which would consist of filling the mold layer by layer in separate operations, in which case there would be potential fragility at the interfaces between each layer.

[0075] The resulting watch component is therefore advantageously a single piece, with the exception of a possible insert. The resulting watch component is therefore advantageously homogeneous. Alternatively, the watch component or timepiece may consist of at least two separate associated parts, at least one part of which is produced using the manufacturing method according to the invention. The watch component may thus have mutually parallel flat surfaces and flanks perpendicular to these flat surfaces, without an inclined surface.

[0076] The watch component may be a watch exterior component such as an applique / index, in particular a godet-shaped applique, or a hand, or a movement component, such as an escape wheel or an anchor or a spring or a nail / rivet. The watch component may have mutually parallel flat surfaces and flanks perpendicular to these flat surfaces. The invention also relates to a timepiece which comprises at least one watch component according to the invention.

Claims

CLAIMS 1. Method of manufacturing a mold for the manufacture of a watch component, characterized in that it comprises the following steps: Deposit (E1.2) a layer N (30) of photosensitive resin; Insolating (E1.3) said photosensitive resin of the N layer (30) of photosensitive resin with insolation radiation (55) according to a first predefined pattern, defining at least a portion (32) of photosensitive resin of the non-insulated N layer (30); Depositing (E1.c) a conductive layer (36) directly on all or part of the surface of the N layer (30) of exposed photosensitive resin; Deposit (E1.4) an optical filter layer (35) directly at least on all or part of the conductive layer (36) and / or its sides; Deposit (E1.5) an N+1 layer (40) of photosensitive resin directly and / or indirectly on the N layer (30) of photosensitive resin, in particular on the conductive layer (36) and / or on said optical filter layer (35).

2. Method for manufacturing a mold according to the preceding claim, characterized in that the step of depositing (E1.c) the conductive layer (36) comprises the deposition on at least the surfaces which are both positioned under the parts of the N+1 layer (40) comprising photosensitive resin intended to be removed to form the mold and which are positioned on the parts of the N layer (30) comprising photosensitive resin intended not to be removed to form the mold.

3. Method of manufacturing a mold according to one of the preceding claims, characterized in that the step consisting of depositing (E1.4) a filter layer optical (35) comprises deposition on the entire upper surface of the conductive layer (36) and / or on the sides of the conductive layer (36).

4. Method of manufacturing a mold according to one of the preceding claims, characterized in that it further comprises the following steps: Insolating (E1.6) said photosensitive resin of the N+1 layer (40) of photosensitive resin with an insolation radiation (65) according to a second predefined pattern defining at least a portion (42) of photosensitive resin of the N+1 layer (40) of non-insulated photosensitive resin; then Developing (E1 .7.1, E1 .7.2) the two layers N, N+1 (30, 40) of photosensitive resin to remove a portion of photosensitive resin from each layer N, N+1 (30, 40) of photosensitive resin defined respectively by said first and second predefined patterns for exposure and to thus form a mold (10) delimited at least partially by said photosensitive resin remaining after development of each layer N, N+1 (30, 40) of photosensitive resin, Or in that it includes the following steps: After the deposition (E1.c) of the conductive layer (36) and before or after the deposition (E1.4) of the optical filter layer (35), and before the deposition (E1.5) of the N+1 layer (40) of photosensitive resin, developing (E1.7.1) the N layer (30) of photosensitive resin to remove a part of photosensitive resin from the N layer (30) of photosensitive resin defined by the first predefined insolation pattern; then in a subsequent separate step, Insolating (E1.6) said photosensitive resin of the N+1 layer (40) of photosensitive resin with an insolation radiation (65) according to a second predefined pattern defining at least a part (42) of photosensitive resin of the N+1 layer (40) of non-insulated photosensitive resin and developing (E1.7.2) the N+1 layer (40) of photosensitive resin to remove a part of photosensitive resin at the less than the N+1 layer (40) of photosensitive resin defined by the second predefined exposure pattern, to thus form a mold (10) delimited at least partially by said photosensitive resin remaining after development (E1.7.2) of each N, N+1 layer (30, 40) of photosensitive resin.

5. Method for manufacturing a mold according to the preceding claim, characterized in that the step consisting of developing (E1.7.1) the N layer (30) of photosensitive resin and / or developing (E1.7.2) the N+1 layer (40) of photosensitive resin is carried out chemically and comprises a step of using ultrasound.

6. Method of manufacturing a mold according to claim 4 or 5, characterized in that said two predefined patterns are such that the development (E1.7.1, E1.7.2) said two layers N, N+1 (30, 40) of photosensitive resin form at least one first cavity (11) of the layer of resin N (30) and at least one second cavity (12) in the layer N+1 (40) of photosensitive resin, this second cavity (12) being superimposed on the first cavity and of larger surface area than the first cavity (11) so that an upper surface of the layer N (30) of photosensitive resin is located directly inside the second cavity (12) of the layer N+1 (40) of photosensitive resin, and in that it comprises a step of removing the possible optical filter layer (35) covering the conductive layer (36) at this upper surface of the layer N (30) which is located in the second cavity (12), so that this upper surface of the layer N (30) of photosensitive resin which is located in the second cavity (12) is covered by said conductive layer (36) which forms a bottom of the second cavity (12). 7.. Method for manufacturing a mold according to claim 4 or 5, characterized in that the optical filter layer (35) makes it possible to filter the wavelengths emitted by the insolation radiation (65) during the step consisting of insolating (E1.6) the photosensitive resin of the N+1 layer (40) of photosensitive resin.

8. Method for manufacturing a mold according to one of the preceding claims, characterized in that the step of exposing (E1.3, E1.6) said resin layer (30, 40) uses an optical filter layer arranged on said resin layer (30, 40) to fulfill the mask function.

9. Method for manufacturing a mold according to one of the preceding claims, characterized in that the step consisting of depositing (E1.c) a conductive layer (36) is carried out by physical vapor deposition (PVD).

10. Method for manufacturing a mold according to one of the preceding claims, characterized in that the step of depositing (E1.4) an optical filter layer (35) is carried out by a spin-coating process, or by a spraying process, or by dip coating, or by chemical vapor deposition (CVD), or physical vapor deposition (PVD), or atomic layer deposition (ALD), or pulsed laser ablation deposition (PLD), or by rolling or pressing processes.

11. Method for manufacturing a mold according to one of the preceding claims, characterized in that it comprises a preliminary step consisting of providing (E1.1) a substrate (20) then a step consisting of depositing a stack of several layers of photosensitive resin superimposed on the upper surface of the substrate, this stack comprising at least said two layers N, N+1 (30, 40) of photosensitive resin, the substrate (20) forming a bottom of the mold after development of the layers of resin.

12. Method for manufacturing a mold according to one of the preceding claims, characterized in that it comprises a development (E1.7.1) of the N layer (30) of photosensitive resin through the conductive layer (36) and / or through the optical filter layer (35).

13. Method for manufacturing a watch component, characterized in that it comprises a first step (E1) corresponding to the method for manufacturing a mold according to one of the preceding claims, and a second step (E2) of forming the watch component comprising a step consisting of filling (E2.1) all or part of said mold with a material (2) of the component.

14. Method for manufacturing a watch component according to the preceding claim, characterized in that the step consisting of filling (E2.1) the mold comprises a step of electroplating, electroforming, electroplating.

15. Method for manufacturing a watch component according to claim 13 or 14, characterized in that the step of filling (E2.1) the mold comprises a single step of filling the entire mold to form a single-piece component.

16. Method for manufacturing a watch component according to one of claims 13 to 15, characterized in that it comprises a step consisting of detaching (E2.3, E2.4) from the mold the watch component obtained by the step consisting of filling (E2.1) the mold, and optionally comprises a finishing step consisting of polishing and / or grinding and / or machining and / or decorating and / or coating and / or coloring at least one face of the watch component, in particular to ensure its height and / or its flatness and / or its decoration.

17. Method of manufacturing a watch component according to one of claims 13 to 16, characterized in that said material (2) of the component is a metal or a metal alloy, in particular based on nickel or gold or copper.

18. Method for manufacturing a watch component according to one of claims 13 to 17, characterized in that the watch component (1) is a watch exterior component such as an applique / index, in particular a godet-shaped applique, or a hand, or a movement component, such as an escape wheel or an anchor or a spring or a nail / rivet, and / or in that the watch component has flat surfaces parallel to each other and sides perpendicular to these flat surfaces.

19. Mold for manufacturing a watch component, characterized in that it comprises a layer N (30) of photosensitive resin forming at least a first cavity (11) of the mold and a layer N+1 (40) of photosensitive resin forming at least a second cavity (12) of the mold, this second cavity (12) being superimposed on the first cavity (11) and of larger surface area than the first cavity (11) so that an upper surface of the layer N (30) of photosensitive resin is located directly inside the second cavity (12) of the layer N+1 (40) of photosensitive resin, in that this upper surface of the layer N (30) of photosensitive resin which is located in the second cavity (12) is covered by a conductive layer (36) which forms a bottom of the second cavity (12), and in that an optical filter layer (35) is in contact with a flank of the conductive layer (36) and is positioned at least partly between the two layers N, N+1 (30,40) of photosensitive resin.,

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