Patent Publication Number: US-8523426-B2

Title: One-piece regulating member and method of manufacturing the same

Description:
This is a National Phase Application in the United States of America of International Patent Application PCT/EP2009/053000 filed Mar. 13, 2009, which claims priority on European Patent Application No. 08153101.4 of Mar. 20, 2008. The entire disclosures of the above patent applications are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The invention concerns a regulating member and the method of manufacturing the same and, more specifically, a sprung balance type regulating member. 
     BACKGROUND OF THE INVENTION 
     The regulating member of a timepiece generally includes an inertia wheel, called a balance, and a resonator called a balance spring. These parts have a determining role as regards the working quality of the timepiece. Indeed, they regulate the movement, i.e. they control the frequency of the movement. 
     The balance and the balance spring are different in nature, which makes it extremely complex to manufacture the regulating member, the manufacturing including the manufacture of the balance and the balance spring and the resonant assembly of the two parts. 
     The balance and the balance spring have thus each been manufactured in different materials, particularly in order to limit the influence of a temperature change, but without resolving the difficulties as regards resonant assembly. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to overcome all or part of the aforecited drawbacks by proposing a one-piece regulating member, which remains insensitive to temperature changes and which is obtained via a manufacturing method that minimises assembly difficulties. 
     The invention thus relates to a one-piece regulating member that includes a balance cooperating with a hairspring, made in a layer of silicon-based material and including a balance spring coaxially mounted on a collet, the collet including one extending part that projects from the balance spring and which is made in a second layer of silicon-based material, characterized in that the extending part of the hairspring collet is secured to the balance. 
     According to other advantageous feature of the invention:
         the balance has a hole that extends the inner diameter of the collet so as to receive a balance staff therein;   the balance staff is secured to the balance;   the balance staff is secured to the balance by being driven against a metal coating made in the hole;   the section of the inner diameter of the collet is larger than that of the hole in the balance to prevent push fit contact between the balance staff and the inner diameter of the collet;   the balance felloe is continuous and includes an adapting device that can alter the moment of inertia of the balance;   the felloe is connected to the balance hub by at least one arm, which is slim so as to allow it to deform axially and/or radially in the event that any shock is transmitted to the balance;   the adapting device includes recesses made on the balance felloe so that the inertia of the balance can be adjusted;   the recesses include a material of much greater density than that of the balance felloe so as to increase the inertia of the balance;   the adapting device includes bosses made on the balance staff and including a material of much greater density than the felloe so as to increase the inertia of the balance;   the balance is made in a third layer of silicon-based material;   the material of much greater density is distributed on the felloe in the form of a notched ring including a series of studs spaced at regular intervals to compensate for any thermal expansion of the material;   the inner coil of the balance spring has a Grossmann type curve to improve the concentric development of the balance spring;   the balance spring includes at least one silicon dioxide based part to make it more mechanically resistant and to adjust its thermo-elastic coefficient.       

     More generally, the invention also relates to a timepiece, characterized in that it includes a one-piece regulating member according to any of the preceding variants. 
     Finally, the invention relates to a method of manufacturing a regulating member including the following steps:
     a) providing a substrate that includes a top layer and a bottom layer made of silicon-based materials;   b) selectively etching at least one cavity in the top layer to define the pattern of a first part of a collet and of a first part of a balance made of silicon-based material of the member;   c) securing an additional layer of silicon-based material to the top, etched layer of the substrate;   d) selectively etching at least one cavity in the additional layer to continue the pattern of the first parts of the collet and balance, and to define the pattern of a balance spring made of silicon-based material of the member;
 
characterized in that it further includes the following steps:
   e) selectively etching at least one cavity in the bottom layer to define the last part of the silicon-based balance of the member;   f) releasing the regulating member from the substrate, which provides a member across three levels of silicon-based material.   

     In accordance with other advantageous features of the invention:
         after step d), step g) is performed: the second part of the member made of silicon-based material is oxidised so as to adjust its thermo-elastic coefficient but also to make it more mechanically resistant,   prior to step e), step h) is performed: at least one layer of metal is selectively deposited on the bottom layer to define the pattern of at least one metal part of the member and/or a second metallic part for receiving an arbour that is driven therein;   step h) includes step i): growing the deposition by successive metallic layers at least partially on the surface of the bottom layer so as to form a metallic part for increasing the mass of the balance made of silicon-based material and/or a second metallic part for receiving an arbour that is driven therein;   step h) includes step j): selectively etching at least one cavity in the bottom layer for receiving the at least one metal part and step k): growing the deposition by successive metal layers at least partially in the at least one cavity so as to form a metal part for increasing the mass of the balance made of silicon-based material and/or a second metal part into which an arbour will be driven,   step h) includes the last step i): polishing the metal deposition,   several members are made on the same substrate, which allows batch manufacture.       

     Thus, in accordance with a first non-limiting illustrative embodiment of the present invention, a one-piece regulating member ( 41 ,  41 ′,  41 ″) is provided that includes a balance ( 43 ,  43 ′,  43 ″) cooperating with a hairspring ( 51 ,  51 ′,  51 ″) made in a layer of silicon-based material ( 21 ) and including a balance spring ( 53 ,  53 ′,  53 ″) coaxially mounted on a collet, characterized in that the collet ( 55 ,  55 ′,  55 ″) includes one extending part ( 19 ) that projects from the balance spring and which is made in a second layer of silicon-based material ( 5 ) and is secured to the balance ( 43 ,  43 ′,  43 ″). In accordance with a second non-limiting illustrative embodiment of the resent invention the first non-limiting embodiment is modified so that the balance ( 43 ,  43 ′,  43 ″) includes a hole ( 26 ) that extends the inner diameter ( 24 ,  10 ) of the collet ( 55 ,  55 ′,  55 ″) so as to receive a balance staff ( 49 ) In accordance with a third non-limiting illustrative embodiment of the present invention, the second non-limiting embodiment is further modified so that the balance staff ( 49 ) is secured to the balance ( 43 ,  43 ′,  43 ″). In accordance with a fourth non-limiting illustrative embodiment of the present invention the third non-limitins embodiment is further modified so that the balance staff ( 49 ) is secured to the balance ( 43 ″,  43 ′) by being driven against a metal coating ( 63 ,  66 ) made in the hole. 
     In accordance with a fifth non-limiting embodiment of the present invention the second third and fourth non-limitin embodiments are further modified so that the section of the inner diameter ( 24 ,  10 ) of the collet ( 55 ,  55 ′,  55 ″) is larger than that of the hole ( 26 ,  63 ,  66 ) of the balance ( 43 ,  43 ′,  43 ″) to prevent push fit contact between the balance staff ( 49 ) and the inner diameter ( 24 ,  10 ) of the collet ( 55 ,  55 ′,  55 ″). In accordance with a sixth non-limiting illustrative embodiment of the present invention, the first, second, third, fourth and fifth non-limiting. embodiments are further modified so that the felloe ( 47 ,  47 ′,  47 ″) of the balance ( 43 ,  43 ′,  43 ″) is continuous and includes an adapting, device ( 61 ,  64 ,  68 ) that can alter the moment of inertia of the balance. In accordance with a seventh non-limiting illustrative embodiment of the present invention, the sixth non-limiting embodiment is further modified so that the felloe ( 47 ,  47 ′,  47 ″) is connected to the hub ( 45 ,  45 ′,  45 ″) of the balance ( 43 ,  43 ′,  43 ″) by at least one arm ( 40 ,  42   44 ,  46 ,  40 ′,  42 ′,  44 ′,  46 ′,  40 ″,  42 ″,  44 ″,  46 ″), which is slim to allow the axial and/or radial deformation thereof in the event of any shock transmitted to the balance ( 41 ,  41 ′,  41 ″). In accordance with an eighth non-limiting illustrative embodiment of the present invention, the sixth and seventh non-limiting embodiments are further modified so that the adaptation device includes recesses ( 60 ,  68 ) made on the felloe ( 47 ,  47 ″) of the balance ( 43 ,  43 ″) so as to adjust the inertia of the balance. In accordance with an ninth non-limiting illustrative embodiment of the present invention, the eighth non-limiting embodiment is further modified so that the recesses ( 60 ) include a material of eater densit, than that of the felloe ( 47 ″) of the balance ( 43 ″) so as to increase the inertia of the balance. In accordance with a tenth non-illustrative embodiment of the resent invention, the sixth and seventh non-limiting embodiments are further modified so that the adaptation device includes bosses ( 61 ) made on the felloe ( 47 ′) of the balance (43′) and includes a material of greater density than the felloe ( 4 ′) so as to increase the inertia of the balance. In accordance with an eleventh non-limiting illustrative embodiment of the present invention the ninth and tenth non-limiting embodiments are further modified so that the material of larger density is distributed on the felloe ( 47 ′,  47 ″) in the form of a notched ring ( 61 ,  64 ) including a series of studs ( 65 ,  69 ) spaced at regular intervals to compensate for any thermal expansion of the material. 
     In accordance with a twelfth non-limiting illustrative embodiment of the present invention, the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth and eleventh non-limiting embodiments are further modified so that the balance  43 ,  43 ′,  43 ″) is made in a third layer ( 7 ) of silicon-based material. In accordance wfth a thirteenth non-limiting illustrative embodiment of the present invention, the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh and twelfth non-limiting embodiments are further modified so that the inner coil of the balance spring ( 53 ,  53 ′,  53 ″) has a Grossmann curve to improve the concentric development of the balance spring. In accordance with a fourteenth non-limiting illustrative embodiment of the present invention, the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh , twelfth and thirteenth non-limiting embodiments are further modified so that the balance spring ( 53 ,  53 ′,  53 ″) has at least one silicon-dioxide based part to make the balance spring more mechanically resistant and to adjust the thermo-elastic coefficient thereof. In accordance with a fifteenth non-limiting illustrative embodiment of the present invention, a timepiece is provided, and characterized in that it includes a regulating member ( 41 ,  41 ′,  41 ″) according to the any one of the first, second, third, fourth, fifth, sixth, seventh eighth. ninth, tenth eleventh, twelfth, thirteenth and fourteenth non-limiting embodiments of the present invention. 
     In accordance with a sixteenth non-limiting embodiment of the present invention, a method ( 1 ) of manufacturing a one-piece regulating member (41, 41′, 41″) is provided wherein the method includes the following steps: (a) providing ( 100 ) a substrate ( 3 ) including a top layer ( 5 ) and a bottom layer ( 7 ) of silicon-based materials, (b) selectively etching ( 101 ) at least one cavity ( 10 ,  11 ) in the top layer ( 5 ) to define the pattern of a first part ( 19 ) of a collet ( 55 ,  55 ′,  55 ″), and a first part ( 17 ) of a balance ( 43 ,  43 ′,  43 ″) made of silicon-based materials, of the member, wherein the method further includes the following steps: (c) joining ( 102 ) an additional layer ( 21 ) of silicon-based material to the etched top layer ( 5 ) of the substrate ( 3 ), (d) selectively etching ( 103 ) at least one cavity ( 20 ,  24 ) in the additional layer ( 21 ) to continue the pattern ( 19 ,  23 ) of the first parts of the collet ( 55 ,  55 ′,  55 ″) and of the balance ( 43 ,  43 ′,  43 ″) and to define the pattern ( 27 ) of a balance spring ( 53 ,  53 ′,  53 ″), made of silicon-based material, of the member, (e) selectively etching ( 105 ,  108 ,  112 ) at least one cavity ( 26 ,  28 ,  29 ,  30 ,  31 ,  32 ) in the bottom layer ( 7 ) to define the last part ( 34 ) of the balance ( 43 ,  43 ′,  43 ″) made of silicon-based material, of the member, and (f) releasing the regulating member ( 41 ,  41 ′,  41 ″) from the substrate ( 3 ). In accordance with a seventeenth non-limiting illustrative embodiment of the present invention, the sixteenth non-limiting embodiment is modified so that, after step (d), the method further includes the following step: (g) oxidising the balance spring ( 53 ,  53 ′,  53 ″) made of silicon-based material, of the member, so as to adjust the thermo-elastic coefficient thereof and also to make the balance spring more mechanically resistant. 
     In accordance with an eighteenth non-limiting illustrative embodiment of the present invention the sixteenth and seventeenth non-limiting embodiments are further modified so that, prior to step (e), the method further includes the following step: (g) selectively depositing ( 107 ,  110 ) at least one metal layer ( 61 ,  63 ,  64 ,  66 ) on the bottom layer ( 7 ) to define the pattern of at least one metal part of the member. In accordance with a nineteenth non-limiting illustrative embodiment of the present invention, the eighteenth embodiment is further modified so that step (h) includes the following step: (i) growing ( 107 ) the deposition by successive metal layers at least partially over the surface of the bottom layer ( 7 ) so as to form a metal part  61  for increasing the mass of the balance ( 43 ′) made of silicon based materials. In accordance with a twentieth non-limiting illustrative embodiment of the present invention the eighteenth and nineteenth non-limiting embodiments of the invention are further modified so that step (h) includes the following phase: growing ( 107 ) the deposition by successive metal layers at least partially over the surface of the bottom layer ( 7 ) so as to form a second metal part ( 63 ) for receiving an arbour ( 49 ) that is driven therein. In accordance with a twenty-first non-limiting illustrative embodiment of the present invention, the eighteenth non-limiting embodiment is further modified so that step (h) includes the following phases: (i) selectively etching ( 109 ) at least one cavity ( 60 ) in the bottom layer ( 7 ) for receiving the at least one metal part; and (k) growing ( 110 ) the deposition by successive metal layers at least partially in the at least one cavity so as to form a metal part ( 64 ) for increasing the mass of the balance ( 43 ″) made of silicon-based materials. 
     In accordance with a twenty-second non-limiting illustrative embodiment of the present invention, the eighteenth and twenty-first non-limiting embodiments are further modified so that step (h) includes the following phases: (j′) selectively etching ( 109 ) at least one cavity ( 62 ) in the bottom layer ( 7 ) for receiving the at least one metal part; and (k&#39;) growing ( 110 ) the deposition by successive metal layers at least partially in the at least one cavity so as to form a second metal part ( 63 ) for receiving an arbour ( 49 ) that is driven therein. In accordance with a twenty-third non-limiting illustrative embodiment of the present invention, the eighteenth, nineteenth, twentieth, twenty-first and twenty-second non-limiting embodiments are further modified so that that step (h) is followed by the following step: (I) polishing ( 111 ) the metal deposition ( 61 ,  63 ,  64 ,  66 ). In accordance with a twenty-fourth non-limiting embodiment of the present invention, the sixteenth, seventeenth, eighteenth, nineteenth, twentieth, twenty-first, twenty-second and twenty-third non-limiting embodiments are further modified so that several regulating members ( 41 ,  41 ′,  41 ″) are made on the same substrate ( 3 ). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages will appear clearly from the following description, which is given by way of non-limiting illustration, with reference to the annexed drawings, in which: 
         FIGS. 1 to 5  show successive views of the manufacturing method according to the invention; 
         FIGS. 6 to 8  shows views of successive steps of alternate embodiments; 
         FIG. 9  shows a flow chart of the method according to the invention; 
         FIGS. 10 and 11  are perspective diagrams of a one-piece regulating member according to a first embodiment; 
         FIGS. 12 and 13  are perspective diagrams of a one-piece regulating member according to a second embodiment; 
         FIGS. 14 and 15  are perspective diagrams of a one-piece regulating member according to a third embodiment; 
         FIG. 16  is a perspective diagram of a one-piece hairspring according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The invention relates to a method, generally designated  1 , for fabricating a regulating member  41 ,  41 ′, and  41 ″ for a timepiece movement. As illustrated in  FIGS. 1 to 9 , method  1  includes successive steps for forming at least one type of one-piece member ( 51 ′″,  41 ,  41 ′,  41 ″), which may be entirely formed of silicon-based materials. 
     With reference to  FIGS. 1 and 9 , the first step  100  consists in taking a silicon-on-insulator (SOI) substrate  3 . Substrate  3  includes a top layer  5  and a bottom layer  7  each formed of silicon-based material. An intermediate layer  9 , formed of silicon dioxide (SiO 2 ) may extend between top layer  5  and bottom layer  7 . 
     Preferably, in this step  100 , substrate  3  is selected such that the height of bottom layer  7  matches the height of one part of the final regulating member  41 ,  41 ′,  41 ″. Moreover, the thickness of bottom layer  7  must be sufficient to bear the efforts induced by method  1 . This thickness may be for example comprised between 300 and 400 μm. 
     Preferably, top layer  5  is used as spacing means relative to bottom layer  7 . Consequently, the height of top layer  5  will be adapted in accordance with the configuration of regulating member  41 ,  41 ′,  41 ″. Depending upon the configuration, the thickness of top layer  5  may thus fluctuate, for example, between 10 and 200 μm. 
     In a second step  101 , seen in  FIG. 2 , cavities  10 ,  11 ,  12 ,  13 ,  14  and  15  are selectively etched, for example by a DRIE (deep reactive ionic etch) process, in top layer  5  of silicon-based material. These cavities  10 ,  11 ,  12 ,  13 ,  14  and  15  preferably form two patterns  17 ,  19  that define the inner and outer contours of silicon parts of the regulating member  41 ,  41 ′,  41 ″. 
     In the example illustrated in  FIG. 2 , patterns  17  and  19  are approximately coaxial and cylinder-shaped with a circular section and pattern  17  has a larger diameter than that of pattern  19 . However, advantageously according to method  1 , the etch on top layer  5  leaves complete freedom as regards the geometry of patterns  17  and  19 . Thus, patterns  17  and  19  are not necessarily circular, but, could be for example, be elliptical and/or have a non-circular inner diameter. 
     Bridges of material  18  are preferably left to hold regulating member  41 ,  41 ′,  41 ″ to substrate  3  during manufacture. In the example illustrated in  FIG. 2 , there are four bridges of material  18 , which remain respectively between each of consecutive cavities  12 ,  13 ,  14  and  15 , distributed in an arc of a circle on the periphery of pattern  17 . 
     In a third step  102 , shown in  FIG. 3 , an additional layer  21  of silicon-based material is added to substrate  3 . Preferably, additional layer  21  is secured to top layer  5  by means of silicon fusion bonding (SFB). Thus, step  102  advantageously covers top layer  5  by binding the top faces of patterns  17  and  19 , with a very high level of adherence, to the bottom face of additional layer  21 . Additional layer  21  may, for example, have a thickness of between 100 and 150 μm. 
     In a fourth step  103 , shown in  FIG. 4 , cavities  20 ,  22  and  24  are selectively etched, for example, by a DRIE process similar to that of step  101 , in additional silicon layer  21 . These cavities  20 ,  22  and  24  form three patterns  23 ,  25  and  27 , which define the inner and outer contours of the silicon parts of regulating member  41 ,  41 ′.  41 ″. 
     In the example illustrated in  FIG. 4 , patterns  23  and  25  are approximately coaxial and cylindrical with a circular section, and pattern  27 , is approximately spiral-shaped. However, advantageously according to method  1 , the etch on additional layer  21  allows complete freedom for the geometry of patterns  23 ,  25  and  27 . Thus, in particular, patterns  23  and  25  are not necessarily circular but may, for example, be elliptical or have a non-circular inner diameter. The same is true for inner diameters  10  and  24 , which are not necessarily circular but may, for example, be polygonal, which would improve the transmission of stress forces in rotation with an arbour  49  of matching shape. Finally, the shape of each diameter  10 ,  24  might not be identical. 
     Preferably, pattern  23  made in additional layer  21  is of similar shape and approximately plumb with pattern  19 , made in top layer  5 . This means that cavities  10  and  24 , respectively forming the inner diameter of patterns  19  and  23 , communicate with each other and are substantially one on top of the other. In the example illustrated in  FIGS. 10 to 15 , patterns  23  and  19  form collet  55 ,  55 ′,  55 ″ of regulating member  41 ,  41 ′,  41 ″ which extends across the top heightswise with respect to layers  5  and  21 . 
     Preferably, pattern  25  made in additional layer  21  is of similar shape and approximately plumb with pattern  17  made in top layer  5 . In the example illustrated, patterns  25  and  17  form one part of the felloe  47 ,  47 ′,  47 ″ of the balance  43 ,  43 ′,  43 ″ of regulating member  41 ,  41 ′,  41 ″ which extends heightswise with respect to layers  5  and  21 . It will be noted, however, that in the example illustrated in  FIG. 4 , bridges of material  18  are not reproduced and that cavity  22  in additional layer  21  forms a continuous ring, unlike cavities  12 ,  13 ,  14  and  15  which open out underneath the layer in  FIG. 4 . 
     Preferably, patterns  23  and  27  are etched at the same time, and form a one-piece part in additional layer  21 . In the example illustrated in  FIGS. 10 to 15 , patterns  23  and  27  form the balance spring  53 ,  53 ′,  53 ″ and the top part of collet  55 ,  55 ′,  55 ″ of regulating member  41 ,  41 ′,  41 ″. It can also be seen that the outer curve of pattern  27  illustrated in  FIG. 4  is open. This latter feature, combined with the separation from bottom layer  7  achieved via pattern  19 , means that the outer curve can be pinned up to the collet using an index assembly. 
     However, advantageously according to method  1 , the etch on additional layer  21  allows complete freedom as to the geometry of pattern  27 . Thus, in particular, pattern  27  might not have an open outer curve but, for example, have a bulge portion on the end of the outer curve that can be used as a point of attachment, i.e. without requiring an index assembly. Pattern  27  may also have an inner coil comprising a Grossmann curve for improving its concentric development, as explained in EP Patent No. 1 612 627 and corresponding U.S. Patent Application Publication No. US 2006/0002241 A1, which are both incorporated herein by reference. 
     After this fourth step  103 , it is clear that patterns  23  and  27  etched in additional layer  21  are only connected by the bottom of pattern  23 , with a very high level of adherence, above pattern  19 , which is etched in top layer  5  (pattern  19  is itself connected, with a very high level of adherence, to bottom layer  7 ). Patterns  23  and  27  are thus no longer in direct contact with additional layer  21 . Likewise, pattern  25  is no longer in direct contest with additional layer  21  but only connected, with a very high level of adherence, to pattern  17 , which is etched in top layer  5 . 
     Preferably, as shown in dotted lines in  FIG. 9 , method  1  can include a fifth step  104  that consists in oxidising at least pattern  27 , i.e. the balance spring  53 ,  53 ′,  53 ″ of regulating member  41 ,  41 ′,  41 ″ so as to make the balance spring more mechanically resistant and to adjust its thermo-elastic coefficient. This oxidising step is explained in EP Patent No. 1 422 436 and corresponding U.S. Patent Application Publication No. US 2005/0281137 A1, which are both incorporated herein by reference. 
     At this stage, i.e. after step  103  or  104 , it is clear that method  1  advantageously produces only hairspring  51 ′″ as seen in  FIG. 16 . Indeed, one of the advantages of method  1  is that it can adapt the height of pattern  19  of collet  55 ,  55 ′,  55 ″,  55 ′″ projecting from balance spring  53 ,  53 ′,  53 ″,  53 ′″ directly, by selecting the height of top layer  5 . 
     When this product  51 ′″, seen in  FIG. 16 , is desired, method  1  can thus simply be stopped at step  103  or  104  by forming bridges of material at the intermediate step. These bridges of material can be formed either on pattern  19  during step  101  or on pattern  27  at the end, for example, of the last coil, during step  103 . The penultimate step of method  1  could then consist in removing bottom layer  7 , for example, by chemical etching and/or mechanical means. Finally, in step  106 , the balance spring  51 ′″ thereby obtained, is released. 
     Advantageously according to the invention, if a regulating member  41 ,  41 ′,  41 ″ is preferred, after fourth step  103 , or preferably after fifth step  104 , method  1  can include three embodiments A, B and C, as illustrated in  FIG. 9 . However, each of the three embodiments A, B and C ends with the same final step  106 , which consists in releasing the manufactured regulating member  41 ,  41 ′,  41 ″ from substrate  3 . 
     Advantageously, release step  106  can be achieved simply by applying sufficient stress to regulating member  41 ,  41 ′,  41 ″ to break bridges of material  18 . This stress may, for example, be generated manually by an operator or by machining. 
     According to embodiment A, in a sixth step  105 , shown in  FIG. 5 , cavities  26 ,  28 ,  29 ,  30 ,  31  and  32  are selectively etched, for example by a similar DRIE process to that of steps  101  and  103 , in bottom layer  7  of silicon-based material. These cavities  26 ,  28 ,  29 ,  30 ,  31  and  32  form a pattern  34 , which defines the inner and outer contours of a silicon part of regulating member  41 . 
     In the example illustrated in  FIG. 5 , pattern  34  is approximately rim-shaped with four arms  40 ,  42 ,  44 ,  46 . However, advantageously according to method  1 , the etch in bottom layer  7  leaves complete freedom as to the geometry of pattern  34 . Thus, in particular, the number and geometry of arms can be different as the rim is not necessarily circular but for example elliptical. Moreover the arms  40 ,  42 ,  44 ,  46  can be slimmer so as to allow them to deform axially and/or radially in the event of any shock transmitted to the regulating member. 
     Preferably, one part of pattern  34  made in bottom layer  7  is of similar shape and approximately plumb with patterns  17  and  25  made respectively in top layer  5  and additional layer  21 . In the example illustrated in  FIG. 5 , pattern  34  forms, with patterns  17  and  25 , the balance  43  of regulating member  41 , whose felloe  47  thus extends heightswise with respect to all of layers  5 ,  7  and  21 . 
     Moreover, preferably, cavity  26  of pattern  34  is approximately in the extension of cavities  10  and  24  that form the inner diameter of patterns  19  and  23 . In the example illustrated, the series of cavities  24 ,  10  and  26  thus forms an inner diameter that can receive balance staff  49  of regulating member  41 . It will be noted, finally, that bridges of material  18  are not reproduced in bottom layer  7  and that cavity  28 , like cavity  22 , forms a continuous ring unlike cavities  12 ,  13 ,  14  and  15  which open out underneath the cavity in  FIG. 5 . 
     After this sixth step  105 , it is clear that pattern  34  etched in bottom layer  7  is only connected, with a very high level of adherence, to patterns  17  and  19 , which are etched in top layer  5 . Pattern  34  is thus no longer in direct contact with bottom layer  7 . 
     After final step  106 , explained above, first embodiment A thus produces a one-piece regulating member  41 , formed entirely of silicon-based materials, as shown in  FIGS. 10 and 11 . It is thus clear that there are no longer any assembly problems, since assembly is performed directly during manufacture of regulating member  41 . The latter includes a balance  43 , whose hub  45  is connected radially to felloe  47  by four arms  40 ,  42 ,  44  and  46 , and axially to hairspring  51 , which includes a balance spring  53  and a collet  55 . 
     As explained above, felloe  47  is formed by the peripheral ring of pattern  34  of bottom layer  7 , but also by patterns  17  and  25  of the respective top  5  and additional 21 layers. Moreover, collet  55  is formed by pattern  23  of additional layer  21  and pattern  19  of top layer  5 . This pattern  19  is preferably used as spacing means between the hairspring  51  and balance spring  43 , so that, for example, balance spring  53  can be pinned up to the collet using an index assembly. Pattern  19  is also useful as guide means for hairspring  51  by increasing the height of collet  55 . 
     However, advantageously according to method  1 , the etch carried out on additional layer  21  allows complete freedom as to the geometry of balance spring  53 . Thus, in particular, balance spring  53  might not have an open outer curve but, for example have, on the end of the outer curve, a bulge portion that can be used as a point of attachment, i.e. without requiring an index assembly. 
     Preferably, regulating member  41  can receive a balance staff  49  through cavities  24 ,  10  and  26 . Advantageously, according to the invention, as regulating member  41  is in one-piece, it is not necessary to secure balance staff  49  to collet  55  and to balance  43 , but only to one of these two members. 
     Preferably, balance staff  49  is be secured to the internal diameter  26  of balance  43  for example using resilient means  48  etched in silicon-based hub  45  during step  105 . These resilient means  48  may, for example, take the form of those disclosed in FIGS. 10A to 10E of EP Patent No. 1 655 642 and its corresponding U.S. Patent Application Publication No. US 2006/0055097 A1, or those disclosed in FIGS. 1, 3 and 5 of EP Patent No. 1 584 994 and its corresponding U.S. Patent Application Publication No. US 2005/0219957 A1, wherein EP 1 655 642 and corresponding U.S. Patent Application Publication No. US 2006/0055097 A1, as well as EP 1 584 994 and corresponding U.S. Patent Application Publication No. US 2005/0219957 A1, are all incorporated herein by reference. Moreover, in a preferred manner, the sections of cavities  24  and  10  have larger dimensions than that of cavity  26  so as to prevent balance staff  49  coming into push fit contact with collet  55 . 
     It is thus clear that the force of hairspring  51  is subjected to balance  43  only by collet  55  and vice versa, since they are all three formed in a single piece. Balance staff  49  therefore only receives forces from regulating member  41  via hub  45  of balance  43 . 
     According to a second embodiment B, after step  103  or  104 , method  1  includes a sixth step  107 , shown in  FIG. 6 , consisting in implementing a LIGA process (from the German “röntgenLlthographie, Galvanoformung &amp; Abformung”). This process includes a series of steps for electroplating a metal on the bottom layer  7  of substrate  3  in a particular shape, using a photostructured resin. As this LIGA process is well known, it will not be described in more detail here. Preferably, the metal deposited may be, for example, gold or nickel or an alloy of these metals. 
     In the example illustrated in  FIG. 6 , step  107  may consist in depositing a notched ring  61  and/or a cylinder  63 . In the example illustrated in  FIG. 6 , ring  61  has a series of studs  65  approximately in the arc of a circle and it is used for increasing the mass of the future balance  43 ′. In fact one of the advantages of silicon is its insensitivity to temperature variations. However, it has the drawback of having low density. A first feature of the invention thus consists in increasing the mass of balance  43 ′ using 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 bottom layer  7  includes a space between each stud  65  that can compensate for any thermal expansion of ring  61 . 
     In the example illustrated in  FIG. 6 , cylinder  63  is for receiving a balance staff  49 , which is advantageously driven therein. In fact, another drawback of silicon is that it has very small elastic and plastic zones, which means that it is very brittle. Another feature of the invention thus consists in tightening balance staff  49 , not against the silicon based material of balance  43 ′, but on the inner diameter  67  of metal cylinder  63 , electroplated during step  107 . Advantageously, according to method  1 , the cylinder  63  obtained by electroplating allows complete freedom as regards its geometry. Thus, in particular, the inner diameter  67  is not necessarily circular, but for example polygonal, which could improve the transmission of force in rotation with an staff  49  of matching shape. 
     In a seventh step  108 , similar to step  105  shown in  FIG. 5 , cavities are selectively etched, for example by a DRIE method, in bottom layer  7  of silicon-based material. These cavities form a similar balance pattern to pattern  34  of embodiment A. As illustrated in the example of  FIGS. 12 and 13 , the pattern obtained may be approximately rim-shaped with four arms  40 ′,  42 ′,  44 ′,  46 ′. However, advantageously according to method  1 , the etch over bottom layer  7  allows complete freedom as to the geometry of pattern  34 . Thus, in particular, the number and geometry of the arms may be different, and the rim is not necessarily circular but, may be, for example, elliptical. Moreover, arms  40 ′,  42 ′,  44 ′,  46 ′ may be slimmer to allow them to deform axially and/or radially in the event of any shock transmitted to the regulating member. 
     Preferably, one part of the balance pattern made in bottom layer  7  is of similar shape and approximately plumb with patterns  17  and  25  respectively made during steps  101  and  103  in top layer  5  and additional layer  21 . In the example illustrated in  FIGS. 12 and 13 , the balance pattern forms, with patterns  17  and  25  and metal parts  61  and/or  63 , the balance  43 ′ of regulating member  41 ′, whose felloe  47 ′ thus extends heightswise with respect to all of layers  5 ,  7  and  21  of metal parts  61  and/or  63 . 
     Moreover, preferably, as in embodiment A, the successive cavities then form an inner diameter that can receive balance staff  49  of regulating member  41 ′. It will be noted, finally, that bridges of material  18  might also not be reproduced in bottom layer  7 . 
     After this seventh step  108 , it is clear that the balance pattern etched in bottom layer  7  is only connected, with a very high level of adherence, to patterns  17  and  19  of bottom layer  5 , which were etched during step  101 . The balance pattern is thus no longer in direct contact with bottom layer  7 . 
     After the final step  106 , explained above, the second embodiment B thus produces a one-piece, regulating member  41 ′, formed of silicon-based materials with one or two metal parts  61 ,  63 , as seen in  FIGS. 12 and 13 . It is thus clear that there is no longer any assembly problem since assembly is carried out directly during manufacture of regulating member  41 ′. The latter includes a balance  43 ′, whose hub  45 ′ is connected radially to felloe  47 ′ by four arms  40 ′,  42 ′,  44 ′ and  46 ′, and axially to hairspring  51 ′, which includes a balance spring  53 ′ and a collet  55 ′. 
     As explained above, felloe  47 ′ is formed by the peripheral ring of the balance pattern of bottom layer  7 , but also by patterns  25  and  17  of top layer  5  and additional layer  21  and, possibly, of metal part  61 . Moreover, collet  55 ′ is formed by pattern  23  of additional layer  21  and pattern  19  of top layer  5 . This pattern  19  is preferably used as spacing means between hairspring  51 ′ and balance  43 ′ so that balance spring  53 ′ can be pinned up to the collet using an index assembly. Pattern  19  is also useful as guide means for hairspring  51 ′ by increasing the height of collet  55 ′. 
     However, advantageously according to method  1 , the etch on additional layer  21  leaves complete freedom as to the geometry of balance spring  53 ′. Thus, in particular, balance spring  53 ′ might not have an open outer curve but, could, for example, have a bulge portion on the end of the outer curve that can be used as a fixed point of attachment, i.e. without requiring an index assembly. 
     Preferably, regulating member  41 ′ is able to receive a balance staff  49  in its inner diameter. Advantageously, according to the invention, as regulating member  41 ′ is in one-piece, it is not necessary to secure balance staff  49  to collet  55 ′ and to balance  43 ′, but only to one of these two members. 
     In the example illustrated in  FIGS. 12 and 13 , balance staff  49  is secured, preferably, to the inner diameter  67  of metal part  63 , for example by being driven therein. Moreover, preferably, the sections of cavities  24  and  10  have larger dimensions than that of inner diameter  67  of metal part  63  to prevent balance staff  49  coming into push fit contact with collet  55 ′. 
     It is clear therefore that the stress of hairspring  51 ′ is only subjected to the balance  43 ′ by collet  55 ′ and vice versa, since all three are formed in one-piece. Balance staff  49  thus preferably only receives forces from regulating member  41 ′ via metal part  63  of hub  45 ′ of balance  43 ′. 
     Moreover, since a metal part  61  has been deposited, the inertia of balance  43 ′ is advantageously amplified. Indeed, as the density of a metal is much greater than that of silicon, the mass of balance  43 ′ is increased as is, incidentally, its inertia. 
     According to a third embodiment C, after step  103  or  104 , method  1  includes a sixth step  109  shown in  FIG. 7 , consisting in selectively etching cavities  60  and/or  62 , for example, by a DRIE process, to a limited depth in bottom layer  7  of silicon-based material. These cavities  60 ,  62  form recesses that can be used as containers for at least one metal part. As in the example illustrated in  FIG. 7 , the cavities  60  and  62  obtained can respectively take the form of a ring and disc. However, advantageously according to method  1 , the etch of bottom layer  7  allows complete freedom as to the geometry of cavities  60  and  62 . 
     In a seventh step  110 , as illustrated in  FIG. 8 , method  1  includes implementation of a galvanic growth or LIGA process for filling cavities  60  and/or  62  in accordance with a particular metal shape. Preferably, the deposited metal may be, for example, gold or nickel. 
     In the example illustrated in  FIG. 8 , step  110  may consist in depositing a notched ring  64  in cavity  60  and/or a cylinder  66  in cavity  62 . Moreover, in the example illustrated in  FIG. 8  ring  64  has a series of studs  69  approximately in the arc of a circle and it is advantageously used for increasing the mass of balance  43 ″. As already explained above, a drawback of the silicon is its low density. Thus as for the embodiment B, a feature of the invention consists in increasing the moss of balance  43 ″ using electroplated metal in order to inverse the inertia of the future balance  43 ″. However, in order to keep the advantages of silicon, the metal deposited on bottom layer  7  includes a space between each stud  69  that can compensate for any thermal expansion of ring  64 . 
     In the example illustrated in  FIG. 8 , cylinder  66  is for receiving a balance staff  49 , which is advantageously driven therein. In fact, as already explained above, one advantageous feature of the invention consists in tightening balance staff  49  not against the silicon-based material, but on the inner diameter  70  of metal cylinder  66 , which is electroplated during step  110 . Advantageously according to method  1 , the electroplated cylinder  66  allows complete 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 force in rotation with an balance staff  49  of matching shape. 
     Preferably, method  1  can include an eighth step  111 , consisting in polishing the metal deposition(s)  64 ,  66  made during step  110 , in order to make them flat. 
     In a ninth step  112 , similar to steps  105  or  108  shown in  FIG. 5 , cavities are selectively etched, for example, by a DRIE process, in bottom layer  7  of silicon-based material. These cavities form a balance pattern similar to pattern  34  of the first embodiment A. As illustrated in the example of  FIGS. 14 and 15 , the pattern obtained may be approximately rim-shaped with four arms  40 ″,  42 ″,  44 ″,  46 ″. However, advantageously according to method  1 , the etch on the bottom layer  7  leaves complete freedom as to the geometry of pattern  34 . Thus, in particular, the number and geometry of arms  40 ″,  42 ″,  44 ″,  46 ″ may be different, and the rim is not necessarily circular, but may be elliptical, for example. Moreover, the arms may be slimmer to allow them to deform axially and/or radially in the event of any shock transmitted to the regulating member. 
     Preferably, the balance pattern made in bottom layer  7  is of similar shape to and approximately plumb with patterns  17  and  25  respectively made during steps  101  and  103  in top layer  5  and additional layer  21 . In the example illustrated, the balance pattern forms, with patterns  17  and  25  and metal parts  64  and/or  66 , the balance  43 ″ of regulating member  41 ″, whose felloe  47 ″ thus extends across the top of all of layers  5 ,  7  and  21 . 
     Moreover, preferably, as in embodiments A and B, the successive cavities thus form an inner diameter that can receive balance staff  49  of regulating member  41 ″. It will be noted, finally, that bridges of material  18  are no longer reproduced in bottom layer  7 . 
     After this ninth step  112 , it is clear that the balance pattern etched in bottom layer  7  is only connected, with a very high level of adherence, to patterns  17  and  19  of top layer  5 , etched during step  101 . The balance pattern is thus no longer in direct contact with bottom layer  7 . 
     After final step  106  explained above, a one-piece, regulating member  41 ″ formed of silicon-based materials, with one or two metal parts  64 ,  66  is obtained, as seen in  FIGS. 14 and 15 . It is thus clear that there are no longer any assembly problems, since assembly is carried out directly during manufacture of the regulating member  41 ″. The latter includes a balance  43 ″, whose hub  45 ″ is radially connected to felloe  47 ″ by four arms  40 ″,  42 ″,  44 ″ and  46 ″ and axially connected to hairspring  51 ″, which includes a balance spring  53 ″ and a collet  55 ″. 
     As explained above, felloe  47 ″ is formed by the peripheral ring of the balance pattern of bottom layer  7 , but also by patterns  25  and  17  of the respective top and bottom layers  5  and  21 , and possibly, metal part  64 . Moreover, collet  55 ″ is formed by pattern  23  of additional layer  21  and pattern  19  of top layer  5 . Preferably, this pattern  19  is used as spacing means between hairspring  51 ″ and balance  43 ″, so that, for example balance spring  53 ″ can be pinned up to the collet using an index assembly. Pattern  19  is also useful as guide means for hairspring  51 ″ by increasing the height of collet  55 ″. 
     However, advantageously according to method  1 , the etch on additional layer  21  leaves complete freedom as to the geometry of balance spring  53 ″. Thus, in particular, balance spring  53 ″ might not have an open outer curve but, could, for example, have a bulge portion on the end of the outer curve that can be used as a fixed point of attachment, i.e. without requiring an index assembly. 
     Preferably, regulating member  41 ′ is able to receive a balance staff  49  in its inner diameter. Advantageously according to the invention, as regulating member  41 ″ is in one-piece, it is not necessary to secure balance staff  49  to collet  55 ″ and to balance  43 ″, but only to one of these two members. 
     In the example illustrated in  FIGS. 14 and 15 , balance staff  49  is secured, preferably, to the inner diameter  70  of metal part  66 , for example be being driven therein. Moreover, preferably, the sections of cavities  24  and  10  have larger dimensions than that of inner diameter  70  of metal part  66  to prevent balance staff  49  coming into push fit contact with collet  55 ″. 
     It is clear therefore that the stress of hairspring  51 ″ is only subjected to the balance  43 ″ by collet  55 ″ and vice versa, since all three are formed in one-piece. Balance staff  49  thus preferably only receives stress forces from regulating member  41 ″ via metal part  66  of hub  45 ″ of balance  43 ″. 
     Moreover, since a metal part  64  has been deposited, the inertia of balance  43 ″ is advantageously amplified. Indeed, as the density of a metal is much greater than that of silicon, the mass of balance  43 ″ is increased as is, incidentally, 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 prior to being structured, i.e. prior to being etched and/or altered by electroplating. This advantageously minimises the dispersions generated by current assemblies of a balance spring with a hairspring. 
     It should also be noted that the very good structural precision of deep reactive ionic etching decreases the start radius of each of balance springs  53 ,  53 ′,  53 ″,  53 ′″, i.e. the external diameter of the collet  55 ,  55 ′,  55 ″,  55 ′″ thereof, which allows the inner and outer diameters of collet  55 ,  55 ′,  55 ″,  55 ′″ to be miniaturised. 
     Advantageously, according to the invention, it is also clear that it is possible for several regulating members  41 ,  41 ′ and  41 ″ to be made on the same substrate  3 , which allows batch production. 
     Of course, the present invention is not limited to the example illustrated, but is capable of various variants and alterations, which will be clear to those skilled in the art. In particular, the patterns  17  and  25  etched during steps  101  and  103  in layers  5  and  21  might not be limited to a flat surface state, but could integrate, during the steps, at least one ornament for decorating at least one of the faces of felloe  47 ,  47 ′,  47 ″, which may be useful, particularly for skeleton type timepieces. 
     It is also possible for the electroplated metal parts  63 ,  66  in embodiments B and C to be inverted, i.e. projecting part  63  of mode B could be replaced by integrated part  66  of mode C or vice versa (which only requires minimum adaptation of method  1 , or even for part  66  integrated in the hub to project from bottom layer  7 . 
     In accordance with similar reasoning, it is also possible for metal parts  61 ,  64  electroplated in embodiments B and C to be inverted, i.e. projecting part  61  of mode B could be replaced by integrated part  64  of mode C or vice versa, or part  64  integrated in the felloe could project from bottom layer  7 . 
     Moreover, method  1  may advantageously also provide, after release step  106 , a step of adapting the frequency of regulating member  41 ,  41 ′,  41 ″. This step could then consist in etching, for example by laser, recesses  68  that can alter the operating frequency of the regulating member. These recesses  68 , as illustrated for example in  FIGS. 10 and 11 , could, for example, be made on one of the peripheral walls of pattern  34  belonging to felloe  47 ,  47 ′,  47 ″ and/or on one of the electroplated metal parts  61 ,  64 . Conversely, inertia-block regulating structures could also be envisaged for increasing inertia and regulating frequency. 
     A conductive layer could also be deposited over at least one part of regulating member  41 ,  41 ′,  41 ″ to prevent isochronism problems. This layer may be of the type disclosed in EP 1 837 722 and in corresponding U.S. Patent Application Publication No. US 2008/0037376 A1, which are both incorporated herein by reference. 
     Finally, a polishing step like step  111  may also be performed between step  107  and step  108 . A step of making a metal deposition  63 ,  66 , of the type obtained by embodiments B and C, could also be envisaged, not on the balance, but, if only hairspring  51 ′″ is being manufactured, on additional layer  21 , so that a staff can be driven, not against the silicon-based material of the inner diameter of collet  55 ′″, but against the metal deposition. 
     In sum then, the present iinvention pertains broadly to a one-piece regulating member ( 41 ,  41 ′,  41 ″) including a balance ( 43 ,  43 ′,  43 ″) cooperating with a hairspring ( 51 ,  51 ′,  51 ″) made in a layer of silicon-based material ( 21 ) and that includes a balance spring ( 53 ,  53 ′,  53 ″) coaxilly mounted on a collet. According to the invention, the collet ( 55 ,  55 ′,  55 ″) includes one extending part ( 19 ) the projects from the balance spring and which is made in a second layer on silicon-based material ( 5 ) and is secured to the balance ( 43 ,  43 ′,  43 ″). The present invention also relates to a timepiece the includes the regulating member and to the associated manufacturing method. The present invention concerns the field of timepiece movements.