CH706252B1 - Method for manufacturing integral single-piece spiral of clock element, involves selectively engraving cavity in additional layer to define portion for spiral spring made of material containing silicon, and releasing spiral of substrate - Google Patents

Abstract

The method involves providing a substrate comprising a roadbase and a sub-base made of materials containing silicon, and selectively engraving a cavity in the roadbase to define a portion (19) for a ferrule (55 ''') made of material containing silicon. The engraved substrate is attached on the roadbase. Another cavity in an additional layer is selectively engraved to continue the portion of the ferrule and to define another portion for a spiral spring (53''') made of material containing silicon. A spiral (51''') of the substrate is released.

Description

Field of the invention

The invention relates to a spiral and its manufacturing process and, more particularly, to a monobloc spiral made of silicon-based material.

Background of the invention

The regulating member of a timepiece generally comprises a flywheel called pendulum and a resonator called spiral. These pieces are decisive for the running quality of the timepiece. Indeed, they regulate the movement, that is to say that they control the frequency of the movement.

The balance and the spiral are different in nature which makes the focus of the regulating organ, which includes the own manufacturing of the balance and the spiral and their assembly substantially in resonance, extremely complex.

The hairspring has thus been manufactured in various materials in particular in order to limit the influence of a temperature change on the regulator member in which it is integrated without the difficulties of assembly or focusing in resonance does not disappear.

Summary of the invention

The object of the present invention is to overcome all or part of the disadvantages mentioned above by proposing a monobloc spiral and whose manufacture, by a process comprising few steps, to improve its intrinsic qualities and, optionally, adjust its thermo-elastic coefficient.

For this purpose, the invention relates to a spiral comprising a spiral spring mounted coaxially on a ferrule, which are made of a single layer of silicon-based material characterized in that the ferrule comprises an extension part. protruding from said coil spring and which is made in a second layer of silicon-based material to be able to match the spacing of said hairspring with another element while improving the guiding of said hairspring.

According to other advantageous features of the invention: the spiral spring has at least one portion of silicon dioxide to make it more mechanically strong and adjust its thermo-elastic coefficient; the ferrule has a uniform inner diameter; the inside diameter of the portion in extension is different from that of the remainder of the ferrule which makes it possible, for example, to make an integral axis that of a part of the ferrule; the inner diameter of the shell comprises at least a portion of the circular section; the inner diameter of the ferrule comprises at least a portion of the polygonal section which improves the transmission of the force by rotation, for example, a correspondingly shaped axis; the ferrule comprises a metal part allowing said spiral to receive by driving an axis which avoids damaging the parts made of silicon-based material; the inner coil of the spiral spring comprises a Grossmann type curve in order to improve the concentricity of the development of said spiral.

More generally, the invention also relates to a timepiece comprising a hairspring according to one of the preceding variants.

[0009] Finally, the invention relates to a method for manufacturing a watchmaker's hairspring comprising the following steps: <tb> a) <sep> provide a substrate comprising an upper layer and a lower layer of silicon-based materials; <tb> b) <sep> selectively etching at least one cavity in the upper layer to define the pattern of a first portion of silicon-based material of said hairspring; <tb> characterized in that it further comprises the following steps: <tb> c) <sep> solidariser, on the etched upper layer of the substrate, an additional layer of silicon-based material; <tb> d) <sep> selectively etching at least one cavity in the additional layer to continue the pattern of said first portion and defining the pattern of a second portion of silicon-based material of said hairspring; <tb> e) <sep> release the hairspring from the substrate.

According to other advantageous features of the invention: the first part of said hairspring is a shell and the second part is a hairspring; during step e), step f) is carried out: the lower layer is removed by etching and / or mechanical etching; after step d), step g) is carried out: oxidizing the second portion of silicon-based material of said hairspring in order to adjust its thermoelastic coefficient but also to make it mechanically more resistant; before step d), step h) is carried out: selectively depositing at least one metal layer on the additional layer to define the pattern of at least one metal part of said spiral for receiving a shaft by driving; step h) comprises phase i): growing said deposition in successive metal layers at least partially on the surface of the additional layer to form a metal part intended to receive by driving an axis; step h) comprises the phases j): selectively etching at least one cavity in the additional layer intended to receive said at least one metal part and k): growing said deposition by successive metallic layers at least partially in said at least one a cavity for forming a metal part for receiving a shaft by driving; that step h) comprises the last phase 1): polishing the metal deposit; several spirals are made on the same substrate which allows a series production.

Brief description of the drawings

Other features and advantages will become apparent from the description which is given below, for information only and not limiting, with reference to the accompanying drawings, in which: <tb> figs. 1 to 5 <sep> represent successive views of the manufacturing process according to the invention; <tb> figs. 6-8 <sep> represent views of successive steps of alternative embodiments; <tb> fig. 9 <sep> represents a block diagram of the process according to the invention; <tb> figs. 10 and 11 <sep> are perspective representations of a one-piece regulator member according to a first embodiment; <tb> figs. 12 and 13 <sep> are perspective representations of a one-piece regulating member according to a second embodiment; <tb> figs. 14 and 15 <sep> are perspective representations of a one-piece regulator member according to a third embodiment; <tb> fig. 16 <sep> is a perspective representation of a one-piece hairspring according to the invention; <tb> fig. 17 <sep> is a representation similar to FIG. fig. 16 in which the outer coil is modified.

Detailed Description of the Preferred Embodiments

The invention relates to a generally annotated process 1 for manufacturing a spiral 51 or a complete regulating member 41, 41, 41 for a timepiece movement. As illustrated in FIGS. 1 to 9, the method 1 comprises successive steps intended to form at least one type of piece 51, 41 monobloc which can be integrally formed of silicon-based materials.

With reference to FIGS. 1and 9, the first step 100 consists in providing a substrate 3 of the silicon-on-insulator type (also known by the acronym SOI). The substrate 3 comprises an upper layer 5 and a lower layer 7 each composed of silicon-based material.

Preferably in this step 100, the substrate 3 is chosen so that the height of the lower layer 7 corresponds to the height of a portion of the final regulator member 41, 41, 41. In addition, the lower layer 7 must have a sufficient thickness to withstand the forces induced by the method 1. Such a thickness may be for example between 300 and 400 microns.

Preferably, the upper layer 5 is used as spacing means relative to the lower layer 7. Therefore, the height of the upper layer 5 will be adapted according to the configuration of the spiral 51 or the regulating member 41, 41, 41. According to said configuration, the thickness of the upper layer 5 can thus oscillate, for example, between 10 and 200 microns.

In a second step 101, as shown in FIG. 2, cavities 10, 11, 12, 13, 14 and 15 are selectively etched, for example by a deep reactive ion etching process (also known as DRIE), in the upper layer 5 of silicon. Preferably, these cavities 10, 11, 12, 13, 14 and 15 make it possible to form two patterns 17, 19 defining the inner and outer contours of silicon parts of the regulating member 41, 41, 41.

In the example illustrated in FIG. 2, the patterns 17 and 19 are substantially in the form of coaxial cylinders with a circular cross-section, the pattern 17 having a larger diameter than that of the pattern 19. However, advantageously according to the method 1, the etching on the upper layer 5 leaves all freedom on the geometry of the patterns 17 and 19. Thus, in particular, the patterns 17 and 19 are not necessarily circular but, for example, elliptical or have a non-circular inner diameter.

Preferably, material bridges 18 are left in order to maintain the substrate 3 the regulator member 41, 41, 41 during its manufacture. In the example illustrated in FIG. 2, there are four material bridges 18 which remain respectively between each of the consecutive cavities 12, 13, 14 and 15 distributed in an arc around the periphery of the pattern 17.

In a third step 102, as shown in FIG. 3, an additional layer 21 of silicon-based material is added to the substrate 3. Preferably, the additional layer 21 is fixed on the upper layer 5 by means of a fusion welding of silicon (also known by the acronym SFB ). Step 102 advantageously allows the upper layer 5 to be covered by bonding with a very strong adhesion, in particular the upper faces of the patterns 17 and 19 on the lower face of the additional layer 21. The additional layer 21 may, for example, comprise a thickness between 100 and 150 μm.

In a fourth step 103, as shown in FIG. 4, cavities 20, 22 and 24 are selectively etched, for example, by a method of the DRIE type similar to that of step 101, in the additional layer 21 of silicon-based material. These cavities 20, 22 and 24 make it possible to form three patterns 23, 25 and 27 defining the inner and outer contours of silicon parts of the regulating member 41, 41, 41.

In the example illustrated in FIG. 4, the patterns 23 and 25 are substantially in the form of coaxial cylinders with a circular section and, the pattern 27, substantially in the form of a spiral. However, advantageously according to the method 1, the etching on the additional layer 21 leaves complete freedom on the geometry of the patterns 23, 25 and 27. Thus, in particular, the patterns 23 and 25 are not necessarily circular but, for example, elliptical or have a non-circular inner diameter. It is the same, especially for inner diameters 10 and 24 which are not necessarily circular but, for example, polygonal which could improve the transmission of rotational force with an axis 49 of corresponding shape. Finally, each diameter 10, 24 may not be of identical shape.

Preferably, the pattern 23 made in the additional layer 21 is of similar shape and substantially perpendicular to the pattern 19 made in the upper layer 5. This means that the cavities 10 and 24 respectively forming the inner diameter of the patterns 19 and 23 communicate together and are substantially one above the other. In the example illustrated in FIGS. 10 to 15, the units 23 and 19 form the shell 55, 55, 55, 55 respectively of the regulating member 41, 41, 41 and the spiral 51 which extends in height on layers 5 and 21.

Preferably, the pattern 25 made in the additional layer 21 is of similar shape and substantially perpendicular to the pattern 17 made in the upper layer 5. In the example shown, the patterns 25 and 17 form part of the serge 47, 47, 47 of the balance 43, 43, 43 of the regulating member 41, 41, 41 which extends in height in particular on the layers 5 and 21. However, it is noted that in the example illustrated in FIG. 4, the material bridges 18 are not reproduced and that the cavity 22 in the additional layer 21 forms a continuous ring, in contrast to the cavities 12, 13, 14 and 15 which open below it in FIG. 4.

Preferably, the patterns 23 and 27 are etched at the same time and form a single piece in the additional layer 21. In the example illustrated in FIGS. 10 to 15, the units 23 and 27 form the spiral spring 53, 53, 53, 53 and the upper part of the shell 55, 55, 55, 55 of the body regulator 41, 41, 41 and the hairspring 51. We also see that the external curve of the pattern 27 illustrated in FIG. 4is open. This last characteristic associated with the spacing with respect to the lower layer 7 produced by the pattern 19 makes it possible to embellish said external curve by means of a raquet.

However, advantageously according to the method 1, the etching on the additional layer 21 leaves all freedom on the geometry of the pattern 27. Thus, in particular, the pattern 27 may not have an open external curve but, for example, include on the end of the outer curve a pad adapted to serve as a fixed attachment point, that is to say without the need for raquetry as, for example, illustrated in FIG. 17.

The pattern 27 may also comprise an internal coil having a Grossmann type curve to improve its development concentricity as explained in EP 1 612 627 incorporated by reference to the present description.

Following this fourth step 103, it is understood that the patterns 23 and 27 etched in the additional layer 21 are only connected by the underside of the pattern 23, with a very strong adhesion, above the pattern 19 engraved with the upper layer 5 (the pattern 19 is itself connected, with a very strong adhesion, to the lower layer 7). The patterns 23 and 27 are therefore no longer in direct contact with the additional layer 21. Similarly, the pattern 25 is no longer in direct contact with the additional layer 21 but only connected, with a very strong adhesion, to the pattern 17 etched of the upper layer 5.

Preferably as shown in dashed lines in FIG. 9, the method 1 may comprise a fifth step 104 which consists in oxidizing at least the unit 27, that is to say the spiral spring 53, 53, 53, 53 of the regulation 41, 41, 41 and spiral 51 in order to adjust its thermo-elastic coefficient but also to make it mechanically more resistant. Such an oxidation step is explained in particular in patent EP 1 422 436 which is incorporated by reference in the present description.

At this stage, that is to say after step 103 or 104, it is understood that the method 1 advantageously provides to produce only the spiral 51 as shown in FIG. 16 or in its variant of FIG. 17. Indeed, one of the advantages of the method 1 is to be able to adapt the height of the pattern 19 of the ferrule 55, 55, 55, 55 projecting from the spiral spring 53, 53, 53 , 53 directly by choosing the thickness of the upper layer 5.

When such a product 51, visible in FIG. 16 or 17, is desired, the method 1 as explained above must be adapted and stop after step 103 or 104. A first adaptation is not to form the draft of the balance rod, c that is, do not etch patterns 17 and 25 in steps 101 and 103.

Incidentally, a second adaptation consists in providing, during the roughing of the patterns 19, 23 or 27, the formation of bridges of material on another part than the pattern 17 which is no longer formed. Such material bridges may in particular be formed either on the pattern 19 during step 101 or on the pattern 27 at the end, for example, of the last turn during step 103. The third adaptation of the method 1 could then consist in removing the lower layer 7, for example, by etching and / or mechanical etching. Finally, in a step 106, the hairspring 51 thus obtained would be released from the substrate 3 as explained below.

Following this step 106, we obtain a spiral 51 monoblock integrally formed of silicon-based materials, as can be seen in FIGS. 16et 17. It is therefore understood that there is no longer any problem of assembly because it is directly made during the manufacture of the hairspring 51. The latter comprises a spiral spring 53 mounted coaxially with a ferrule 55.

As explained above, the shell 55 is formed by the pattern 23 of the additional layer 21 and the pattern 19 of the upper layer 5. Preferably, this pattern 19 is used as spacing means between the spiral 51 and another member so as to be able, for example, pit the spiral spring 53 with a raquetetterie using the variant of the open outer curve type of FIG. 16. The pattern 19 is also useful as a guide means of the hairspring 51 by increasing the height of the shell 55.

However, advantageously according to the method 1, the etching on the additional layer 21 leaves all freedom on the geometry of the spiral spring 53. Thus, in particular, the spiral spring 53 may not have an open external curve but, for example as illustrated in FIG. 17, have on the end of the outer curve a stud adapted to serve as a fixed attachment point, that is to say without the need for raquetry.

Preferably, the hairspring 51 is adapted to receive a rocker shaft by the cavities 24 and 10. Such an axis can be fixed to the inner diameter 24 or 10 of the shell 55, for example to using elastic means etched in a portion of the ferrule 55 made of silicon-based material. Such elastic means may, for example, take the form of those disclosed in FIGS. 10A to 10E of EP 1 655 642 or those disclosed in FIGS. 1, 3 and 5 of EP 1 584 994, which patents are incorporated by reference in the present description.

Of course, the general shape of the ferrule 55 is not limited to the examples of FIGS. 16 and 17. Thus, its internal diameter, that is to say the cavities 24 and 10 may or may not be uniform. Indeed, for example, the cavity 10 of the pattern 19 could be of circular section and generally larger than that of the cavity 24 of the pattern 23 which could be of polygonal shape. Such a configuration would make it possible to cooperate, preferentially against the internal diameter of the pattern 23, a polygonal outer surface axis of shape corresponding to that of the cavity 24.

Advantageously according to the invention, if a regulating member 41, 41, 41 is preferred, after the fourth step 103 or preferably after the fifth step 104, the method 1 may comprise three embodiments A, B and C as shown in fig. 9. However, each of the three embodiments A, B and C ends with the same final step 106 of releasing the substrate 3 the regulator 41, 41, 41 manufactured.

Advantageously, the release step 106 can then be simply performed by providing a force to the regulating member 41, 41, 41 able to break its material bridges 18. This effort can, for example, be generated manually by an operator or by machining.

According to the embodiment A, in a sixth step 105, as shown in FIG. 5, cavities 26, 28, 29, 30, 31 and 32 are selectively etched, for example, by a method of the DRIE type similar to that of steps 101 and 103, in the lower layer 7 of silicon-based material. These cavities 26, 28, 29, 30, 31 and 32 make it possible to form a pattern 34 defining the inner and outer contours of a silicon part of the regulating member 41.

In the example illustrated in FIG. 5, the pattern 34 is substantially in the form of a four-armed rim. However, advantageously according to the method 1, the etching on the lower layer 7 leaves all freedom on the geometry of the pattern 34. Thus, in particular, the number and the geometry of the arms can be different just as the rim is not necessarily circular but for example, elliptical. In addition, the arms may be slender to allow their deformation in case of shock transmitted to the regulating member.

Preferably, part of the pattern 34 made in the lower layer 7 is of similar shape and substantially perpendicular to the patterns 17 and 25 made respectively in the upper and additional layers 5 and 21. In the example illustrated in FIG. . 5, the pattern 34 forms, with the patterns 17 and 25, the balance 43 of the regulating member 41, the serge 47 therefore extends in height over all of the layers 5, 7 and 21.

In addition, preferably, the cavity 26 of the pattern 34 is substantially in extension of the cavities 10 and 24 forming the inner diameter of the patterns 19 and 23. In the illustrated example, the successive cavities 24, 10 and 26 thus form a inner diameter adapted to receive the balance shaft 49 of the regulating member 41. Finally, it is noted that in the example illustrated in FIG. 5, the bridges of materials 18 are not reproduced in the lower layer 7 and that the cavity 28, in the manner of the cavity 22, forms a continuous ring contrary to the cavities 12, 13, 14 and 15 which are open under it to fig. 5.

Following this sixth step 105, it is understood that the pattern 34 etched in the lower layer 7 is only connected, with a very strong adhesion, to the patterns 17 and 19 etched of the upper layer 5. The pattern 34 n is therefore more in direct contact with the lower layer 7.

Following the final step 106 explained above, we thus obtain, using the first embodiment A, a monoblock regulator member 41 integrally formed of silicon-based materials, as can be seen in FIGS. . 10 and 11. It is thus clear that there is no longer any problem of assembly because it is directly made during the manufacture of the regulating member 41. The latter comprises a rocker 43 whose hub 45 is connected on the one hand radially to the serge 47 by four arms 40, 42, 44 and 46 and, on the other hand, axially to the hairspring 51, the hairspring 51 comprises a hairspring 53 and a shell 55.

As explained above, the serge 47 is formed by the peripheral ring of the pattern 34 of the lower layer 7 but also by the patterns 17 and 25 of the respective upper 5 and supplementary layers 21. In addition, the ferrule 55 is formed by the pattern 23 of the additional layer 21 and the pattern 19 of the upper layer 5. Preferably, this pattern 19 is used as spacing means between the spiral 51 and the balance 43 so as to be able, for example, to punctuate the spiral spring 53 using a raquet. The pattern 19 is also useful as a guide means of the hairspring 51 by increasing the height of the shell 55.

However, advantageously according to the method 1, the etching on the additional layer 21 leaves all freedom on the geometry of the spiral spring 53. Thus, in particular, the spiral spring 53 may not have an open external curve but, for example, for example, having on the end of the outer curve a bead adapted to serve as a fixed attachment point, that is to say without the need for raquetry.

Preferably, the regulating member 41 is adapted to receive a balance shaft 49 by the cavities 24, 10 and 26. Advantageously according to the invention, the regulator member 41 being integral, it is not necessary to fix the balance shaft 49 to the shell 55 and the balance 43 but only to one of the two.

Preferably, the balance shaft 49 is fixed on the inner diameter 26 of the beam 43 for example by means of elastic means 48 etched in the hub 45 of silicon-based material. Such elastic means 48 may, for example, take the form of those disclosed in FIGS. 10A to 10E of the patent EP 1 655 642 or those disclosed in FIGS. 1, 3 and 5 of EP 1 584 994, which patents are incorporated by reference in the present description. In addition, preferably, the cavities 24 and 10 have sections of larger dimensions than that of the cavity 26 to prevent the balance shaft 49 is in bold contact with the ferrule 55.

It is therefore understood that the force of the spiral 51 is subjected to the beam 43 only by the ferrule 55 and vice versa because they are all three integrally formed. The balance shaft 49 thus receives force from the regulating member 41 only through the hub 45 of the balance 43.

According to a second embodiment B, the method 1 comprises, after step 103 or 104, a sixth step 107, as shown in FIG. 6, consisting in implementing a process of the LIGA type (well-known acronym from the German "Röntgenlithographie, Galvanoformung und Abformung"). Such a process comprises a succession of steps making it possible to electrodeposit in a particular form a metal on the lower layer 7 of the substrate 3 with the aid of a photostructured resin. As this process of the LIGA type is well known, it will not be more detailed below. Preferably, the deposited metal may be, for example, gold or nickel or one of their alloys.

In the example illustrated in FIG. 6, step 107 may consist in depositing a crenellated ring 61 and / or a cylinder 63. In the example illustrated in FIG. 6, the ring 61 comprises a series of pads 65 substantially in a circular arc and is intended to advantageously increase the mass of the future beam 43. Indeed, one of the advantages of silicon is its low sensitivity to temperature variations. However, it has the disadvantage of having a low density. A first characteristic of the invention therefore consists in increasing the mass of the rocker 43 with the aid of metal obtained by electroplating in order to increase the inertia of the future rocker 43. However, in order to keep the advantages of silicon, the metal deposited on the lower layer 7 has a spacing between each pad 65 able to compensate for the thermal expansions of the ring 23.

In the example illustrated in FIG. 6, the cylinder 63 is intended to receive, advantageously, by driving a balance shaft 49. Indeed, another disadvantage of silicon lies in its very weak areas of elastic and plastic which makes it very brittle. Another characteristic of the invention is therefore to achieve the clamping of the balance shaft 49 not against the silicon of the balance 43 but on the inner diameter 67 of the metal cylinder 63 electrodeposited during step 107. Advantageously according to the method 1, the cylinder 63 obtained by electroplating leaves full freedom as to its geometry. Thus, in particular, the inner diameter 67 is not necessarily circular but, for example, polygonal which could improve the transmission of rotational force with an axis 49 of corresponding shape.

In a seventh step 108, similar to the step 105 visible in FIG. 5, cavities are selectively etched, for example, by a method of the DRIE type, in the lower layer 7 of silicon-based material. These cavities make it possible to form a rocker pattern similar to the pattern 34 of embodiment A. As illustrated in the example of FIGS. 12 and 13, the pattern obtained may be substantially in the form of four-armed rim. However, advantageously according to the method 1, the etching on the lower layer 7 leaves all freedom on the geometry of the pattern 34. Thus, in particular, the number and the geometry of the arms can be different just as the rim is not necessarily circular but for example, elliptical. In addition, the arms may be slender to allow their deformation in case of shock transmitted to the regulating member.

Preferably, a rocker pattern portion made in the lower layer 7 is of similar shape and substantially perpendicular to the patterns 17 and 25 made respectively in steps 101 and 103 in the upper layers 5 and 21. example illustrated in FIGS. 12 and 13, the pendulum pattern forms, with the patterns 17 and 25 and the metal parts 61 and / or 63, the balance 43 of the regulating member 41, the serge 47 therefore extends in height on the all layers 5, 7 and 21 and metal parts 61 and / or 63.

In addition, preferentially, as in embodiment A, the successive cavities thus form an inside diameter adapted to receive the balance shaft 49 of the regulating member 41. Finally, it can be noted that the material bridges 18 can not be reproduced either in the lower layer 7.

As a result of this seventh step 108, it is understood that the rocker pattern engraved in the lower layer 7 is only connected, with a very strong adhesion, to the patterns 17 and 19 of the upper layer 5 etched at the same time. step 101. The pendulum pattern is no longer in direct contact with the lower layer 7.

As a result of the final step 106 explained above, using a second embodiment B, a monoblock regulator 41 made of silicon-based materials with one or two parts is thus obtained. 61, 63 of metal as visible in figs. 12 and 13. It is thus clear that there is no longer any problem of assembly because it is directly carried out during the manufacture of the regulating member 41. The latter comprises a rocker 43 whose hub 45 is connected on the one hand radially to the serge 47 by four arms 40, 42, 44 and 46 and, on the other hand, axially to the spiral 51 , the spiral 51 comprises a spiral spring 53 and a ferrule 55.

As explained above, the serge 47 is formed by the peripheral ring of the pendulum pattern of the lower layer 7 but also by the patterns 25 and 17 of the respective upper 5 and additional 21 layers and, optionally, of the metal part 61. In addition, the shell 55 is formed by the pattern 23 of the additional layer 21 and the pattern 19 of the upper layer 5. Preferably, this pattern 19 is used as spacing means between the spiral 51 and the balance 43 so as to pit the spiral spring 53 with a raquetetterie. The pattern 19 is also useful as a guide means of the hairspring 51 by increasing the height of the shell 55.

However, advantageously according to the method 1, the etching on the additional layer 21 leaves complete freedom on the geometry of the spiral spring 53. Thus, in particular, the spiral spring 53 may not have an open external curve but, for example, have on the end of the outer curve a bead adapted to serve as a fixed attachment point, that is to say say without the need for snowshoeing.

Preferably, the regulator member 41 is adapted to receive a balance shaft 49 in its inside diameter. Advantageously according to the invention, the regulating member 41 being in one piece, it is not necessary to fix the balance shaft 49 to the shell 55 and the balance 43 but only to one of the two.

In the example illustrated in the figures, the balance shaft 49 is preferably fixed on the inner diameter 67 of the metal part 63, for example by driving. In addition, preferably, the cavities 24 and 10 have sections of larger dimensions than the inside diameter 67 of the metal part 63 in order to prevent the balance shaft 49 from being in bold contact with the ferrule 55.

It is therefore understood that the force of the spiral 51 is subjected to the beam 43 only by the ferrule 55 and vice versa because they are all three integrally formed. The balance shaft 49 thus receives force from the regulating member 41 only, preferably, via the metal part 63 of the hub 45 of the balance 43.

In addition, insofar as a metal portion 61 has been deposited, the inertia of the balance 43 is advantageously amplified. Indeed, the density of a metal being much greater than that of silicon, the mass of the balance 43 is increased and, incidentally, also its inertia.

According to a third embodiment C, the method 1 comprises, after step 103 or 104, in a sixth step 109, as shown in FIG. 7, selectively etching cavities 60 and / or 62, for example, by a DRIE-type method, at a limited depth in the lower layer 7 of silicon-based material. These cavities 60, 62 make it possible to form recesses able to serve as containers for at least one metal part. As in the example illustrated in FIG. 7, the cavities 60 and 62 obtained can be respectively ring-shaped and disk. However, advantageously according to the method 1, the etching on the lower layer 7 leaves complete freedom on the geometry of the cavities 60 and 62.

In a seventh step 110, as illustrated in FIG. 8, the method 1 comprises the implementation of a galvanic growth type or LIGA type process for filling cavities 60 and / or 62 in a particular metallic form. Preferably, the deposited metal may be, for example, gold or nickel or one of their alloys.

In the example illustrated in FIG. 8, step 110 may consist in depositing a castellated ring 64 in the cavity 60 and / or a cylinder 66 in the cavity 62. In addition, in the example illustrated in FIG. 8, the ring 64 comprises a series of pads 69 substantially in a circular arc and is intended to advantageously increase the mass of the future beam 43. Indeed, as already explained above, a disadvantage of silicon lies in its low density. Thus, as for embodiment B, a characteristic of the invention therefore consists in increasing the mass of balance 43 with metal obtained by electroplating in order to increase the inertia of the future balance 43. However, in order to keep the advantages of silicon, the metal deposited on the lower layer 7 has a spacing between each pad 69 able to compensate for the thermal expansion of the ring 64.

In the example illustrated in FIG. 8, the cylinder 66 is intended to receive, advantageously, by driving a balance shaft 49. Indeed, as already explained above, an advantageous characteristic according to the invention consists in making the clamping of the balance shaft 49 no not against the silicon-based material but on the inside diameter 70 of the metal cylinder 66 electrodeposited during step 110. Advantageously according to method 1, the cylinder 66 obtained by electroplating leaves full freedom as to its geometry. Thus, in particular, the inner diameter 70 is not necessarily circular but, for example, polygonal which could improve the transmission of rotational force with an axis 49 of corresponding shape.

Preferably, the method 1 may comprise, in an eighth step 111, polishing the metal deposit or deposits 64, 66 made during step 110 in order to make them planar.

In a ninth step 112, similar to steps 105 or 108, particularly visible in FIG. 5, cavities are selectively etched, for example, by a method of the DRIE type, in the lower layer 7 of silicon-based material. These cavities make it possible to form a rocker pattern similar to the pattern 34 of embodiment A. As illustrated in the example of FIGS. 14 and 15, the pattern obtained may be substantially in the form of four-armed rim. However, advantageously according to the method 1, the etching on the lower layer 7 leaves all freedom on the geometry of the pattern 34. Thus, in particular, the number and the geometry of the arms can be different just as the rim is not necessarily circular but for example, elliptical. In addition, the arms may be slender to allow their deformation in case of shock transmitted to the regulating member.

Preferably, the pendulum pattern made in the lower layer 7 is of similar shape and substantially perpendicular to the patterns 17 and 25 made respectively in steps 101 and 103 in the upper and additional layers 5 and 21. In the illustrated example, the balance pattern forms, with the patterns 17 and 25 and the metal parts 64 and / or 66, the balance 43 of the regulating member 41, the serge 47 therefore extends in height on all layers 5, 7 and 21.

In addition, preferentially, as in embodiment A, the successive cavities thus form an inside diameter adapted to receive the balance shaft 49 of the regulator member 41. Finally, it is noted that the material bridges 18 are not reproduced either in the lower layer 7.

Following this ninth step 112, it is understood that the rocker pattern engraved in the lower layer 7 is only connected, with a very strong adhesion, to the patterns 17 and 19 of the upper layer 5 etched at the same time. step 101. The pendulum pattern is no longer in direct contact with the lower layer 7.

Following the final step 106 explained above, we thus obtain a monobloc regulator member 41 formed of silicon-based materials with one or two parts 64, 66 of metal as visible in FIGS. 14and 15. It is therefore understood that there is no longer a problem of assembly because it is directly achieved during the manufacture of the regulating member 41. The latter comprises a rocker 43 whose hub 45 is connected on the one hand radially to the serge 47 by four arms 40, 42, 44 and 46 and, on the other hand, Partly, axially to the hairspring 51, the hairspring 51 comprising a hairspring 53 and a hoop 55.

As explained above, the serge 47 is formed by the peripheral ring of the rocker pattern of the lower layer 7 but also by the patterns 25 and 17 of the respective upper 5 and additional 21 layers and, optionally, of the metal part 64. In addition, the shell 55 is formed by the pattern 23 of the additional layer 21 and the pattern 19 of the upper layer 5. Preferably, this pattern 19 is used as spacing means between the spiral 51 and the balance 43 so as to be able, for example, pit the spiral spring 53 with a raquetetterie. The pattern 19 is also useful as a guide means of the hairspring 51 by increasing the height of the shell 55.

However, advantageously according to the method 1, the etching on the additional layer 21 leaves all freedom on the geometry of the spiral spring 53. Thus, in particular, the spiral spring 53 may not have an open external curve but, for example, have on the end of the outer curve a bead adapted to serve as a fixed attachment point, that is to say to say without need of raquetterie.

Preferably, the regulating member 41 is adapted to receive a balance shaft 49 in its inside diameter. Advantageously according to the invention, the regulating member 41 being integral, it is not necessary to fix the balance shaft 49 to the shell 55 and the balance 43 but only to one of the two .

Preferably, in the example illustrated in FIGS. 14 and 15, the balance shaft 49 is fixed on the inner diameter 70 of the metal part 66, for example by driving. In addition, preferably, the cavities 24 and 10 have sections of larger dimensions than the internal diameter 70 of the metal portion 66 to prevent the balance shaft 49 is in bold contact with the ferrule 55 .

It is therefore understood that the force of the hairspring 51 is subjected to the beam 43 only by the shell 55 and vice versa because they are all three integrally formed. The balance shaft 49 thus receives force from the regulating member 41 only, preferably, via the metal part 66 of the hub 45 of the balance 43.

In addition, insofar as a metal portion 64 has been deposited, the inertia of the balance 43 is advantageously amplified. Indeed, the density of a metal being much greater than that of silicon, the mass of the balance 43 is increased and, incidentally, also its inertia.

According to the three embodiments A, B and C, it should be understood that the final regulating member 41, 41 and 41 is thus assembled before being structured, that is to say before be etched and / or modified by electrodeposition. This advantageously makes it possible to minimize the dispersions generated by the current assemblies of a balance with a hairspring.

It should also be noted that the very good structural accuracy of a deep reactive ion etching makes it possible to reduce the starting radius of each of the spiral spring 53, 53, 53, 53, which is that is to say, the outer diameter of their shell 55, 55, 55, 55, which allows the miniaturization of the inner and outer diameters of the ferrule 55, 55, 55, 55 .

Advantageously according to the invention, it is also understood that it is possible for several regulating members 41, 41, 41 and spirals 51 to be made on the same substrate 3, which authorizes mass production. .

Of course, the present invention is not limited to the illustrated example but is susceptible of various variations and modifications that will occur to those skilled in the art. In particular, the patterns 17 and 25 etched in steps 101 and 103 in the layers 5 and 21 may not be limited to a plane surface state but may incorporate in said steps at least one ornament for decorating at least one of the faces of the serge 47, 47, 47 which can be useful in particular in the case of timepieces of the skeleton type.

It is also possible that the metal parts 63, 66 electrodeposited according to the embodiments B and C are interchanged, that is to say that the projecting portion 63 of the B mode is replaced by the integrated part 66 of the mode C or vice versa (which requires only a slight adaptation of the method 1) or even that the portion 66 integrated in the hub protrudes from the lower layer 7.

According to similar reasoning, it is also possible for the metal parts 61, 64 electrodeposited in Embodiments B and C to be interchanged, that is to say that the projecting portion 61 of the B mode is replaced by the integrated part 64 of the mode C or vice versa or even that the part 64 integrated in the serge protrudes from the lower layer 7.

In addition, advantageously, the method 1 may furthermore provide, a posteriori of the release step 106, a step of adapting the frequency of the regulating member 41, 41, 41. Such a step could then consist in engraving, for example by laser, recesses 68 able to modify the operating frequency of said regulator member. Such recesses 68, as illustrated in the example of FIGS. 10 and 11, could, for example, be made on one of the peripheral walls of the pattern 34 belonging to the serge 47, 47, 47 and / or on one of the electroplated metal parts 61, 64. Conversely, regulating structures of the flyweight type can also be considered in order to increase the inertia and adjust the frequency.

It may also be provided that a conductive layer is deposited on at least a portion of the spiral 51 to avoid problems of isochronism. Such a layer may be of the type disclosed in EP 1 837 722 incorporated by reference in this specification.

Finally, a polishing step of the type of step 111 can also be performed between step 107 and step 108. It can also be envisaged that a step of producing a metal deposit 63, 66 of the type obtained by embodiments B or C, is not carried out on the balance but, in the case of the manufacture of the balance spring 51, on the additional layer 21 before step 103 or on the upper layer 5 after step 106 so as to be able to drive an axis not against the silicon-based material of the inner diameter of ferrule 55 but against said metal deposit.

Claims (18)

A method of manufacturing (1) a hairspring (51) comprising the steps of: <tb> a) <sep> providing (100) a substrate (3) having an upper layer (5) and a lower layer (7) of silicon-based materials; <b> <b> <sep> selectively (101) engraving at least one cavity (10, 11) in the top layer (5) to define the pattern (19) of a first portion (55) of material silicon base of said spiral; <tb> characterized in that it further comprises the following steps: <tb> c) <sep> secure (102), on the upper layer (5) etched of the substrate (3), an additional layer (21) of silicon-based material; <tb> d) <sep> selectively (103) etching at least one cavity (20, 24) in the additional layer (21) to continue the pattern (19, 23) of said first portion (55) and defining the pattern (27) of a second portion (53) of silicon-based material of said hairspring; <tb> e) <sep> releasing (106) the hairspring (51) of the substrate (3). 2. Manufacturing process according to the preceding claim, characterized in that the first part of said hairspring is a ferrule (55) and the second part is a spiral spring (53). 3. Method according to claim 1 or 2, characterized in that step e) comprises the following step: <tb> f) <sep> remove the lower layer (7) by etching and / or mechanical etching. 4. Method according to one of the preceding claims, characterized in that it further comprises after step d) the following step: <tb> g) <sep> oxidize the second portion (53) of silicon-based material of said hairspring in order to adjust its thermoelastic coefficient but also to make it mechanically more resistant. 5. Manufacturing process according to one of the preceding claims characterized in that it further comprises before step d) the following step: <tb> h) <sep> selectively depositing (107, 110) at least one metal layer on the additional layer (21) to define the pattern of at least a metal portion of said hairspring. 6. Manufacturing process according to claim 5, characterized in that step h) comprises the following phase: <tb> i) <sep> growing (107) said deposition by successive metal layers at least partially on the surface of the additional layer (21) to form a metal portion (63) for receiving a shaft by driving. 7. Manufacturing process according to claim 5, characterized in that step h) comprises the following phases: <tb> j) <sep> selectively (109) etching at least one cavity (62) in the additional layer (21) for receiving said at least one metal portion; <tb> k) <sep> growing (110) said deposition in successive metal layers at least partially in said at least one cavity to form a metal portion (63) for receiving by driving an axis. 8. Manufacturing process according to one of claims 6 to 7, characterized in that step h) comprises the following last phase: <tb> I) <sep> polish (111) the metal deposit (63, 66). 9. Manufacturing process according to one of the preceding claims, characterized in that several spirals (51) are formed on the same substrate (3). Spiral (51) comprising a spiral spring (53) mounted coaxially on a ferrule (55), which are made in a same layer (21) of silicon-based material characterized in the ferrule (55) has an extension portion (19) projecting from said spiral spring (53) and which is formed in a second layer (5) of silicon-based material so as to be able to adapting the spacing of said hairspring (51) relative to another element while improving the guiding of said hairspring. 11. Spiral according to claim 10, characterized in that the spiral spring (53) comprises at least one portion of silicon dioxide to make it more mechanically resistant and adjust its thermo-elastic coefficient. 12. Spiral according to claim 10 or 11, characterized in that the shell (55) has a uniform inner diameter (10, 24). 13. Spiral according to claim 10 or 11, characterized in that the inner diameter (10) of the portion (19) in extension is different from that (24) of the remainder of the shell (55). 14. Spiral according to one of claims 10 to 13, characterized in that the inner diameter of the shell (55) comprises at least a portion of the circular section. 15. Spiral according to one of claims 10 to 14, characterized in that the inner diameter of the ferrule (55) comprises at least a portion of the section of polygonal shape. 16. Spiral according to one of claims 10 to 15, characterized in that the ferrule (55) comprises a metal part allowing said spiral to receive by driving an axis. 17. Spiral according to one of claims 10 to 16, characterized in that the inner coil of the spiral spring (53) comprises a Grossmann type curve to improve the concentricity of the development of said spiral. 18. Timepiece characterized in that it comprises a hairspring (51) according to one of claims 10 to 17.