JP2015179067A - Manufacturing method of balance spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a balance spring that can highly accurately and easily adjust a rate of the balance spring made up of a crystal material.SOLUTION: A manufacturing method of a balance spring 10 that includes a collet 12 having a through-hole 12a for fitting with a rotating shaft body, and a coil-shaped main spring unit 11 being connected to the collet 12 in a connection unit 12b and being winded around the collet 12 centering around the through-hole 12a, and is obtained by machining a material having a prescribed crystal structure comprises: a rate measurement process of measuring a rate; and a laser irradiation process of irradiating a prescribed area E of the main spring unit 11 facing the connection unit 12b across the through-hole 12a of the collet 12 with a laser. The manufacturing method of the balance spring is configured to cause the laser irradiation to change an area E of the main spring unit 11 to amorphousness, which in turn adjusts the rate.

Description

  The present invention relates to a timepiece mainspring device, and more particularly to an improvement in a method for manufacturing a hairspring in a speed adjusting mechanism.

  2. Description of the Related Art Conventionally, a mechanical timepiece has a speed control mechanism (temp) configured by a hairspring, a balance wheel, and the like in order to maintain a constant rate (degree of advance or delay of the time per day). Here, the balance spring is designed to have excellent isochronism, and the balance regularly reciprocates by the expansion and contraction of the balance spring by the spring force.

  Further, the balance is connected to a mechanism called an escapement composed of a escape wheel and an ankle, and energy is transmitted from the balance spring, so that the reciprocating motion of the balance is converted into a rotational motion. The hairspring is usually formed by processing a metal. For this reason, the shape as designed is often not obtained due to variations in processing accuracy, the influence of internal stress of the metal, and the like.

  However, since the balance spring needs to reciprocate the balance regularly at a predetermined rate, if the shape as designed is not obtained, the balance cannot be moved isochronously, resulting in a deviation in the rate of the watch. Will occur. In a typical timepiece mechanism that is widely known as a means for adjusting the rate deviation, the outer periphery of the hairspring comes into contact with a whisker stick (or a hair support) attached to the quick and slow mechanism, so that the hairspring of the hairspring is adjusted. The watch's rate is adjusted by changing the effective length. A slow / fast needle is attached to the slow / fast mechanism, and the rate is adjusted by operating the slow / fast needle.

  However, such a slow / slow mechanism can cause the balance spring to expand and contract by causing the outer periphery of the balance spring to come into contact with the whisker bar constituting the slow / slow mechanism due to a change in the rotation angle of the balance wheel or a change in the posture of the watch. There was a phenomenon that the rate was unstable due to the limitation and the reciprocating motion of the balance. In addition, since the slow / fast mechanism needs to operate the slow / fast hand, it needs to have a certain size as a structure, which has hindered downsizing of the timepiece.

  In view of the above background, there has been a proposal for manufacturing a hairspring by an etching technique using a material having a crystal structure such as quartz or silicon instead of a metal material. As is well known, this etching processing technology can process a crystal material with high accuracy, and since there is less variation in processing accuracy than general metal balance springs, a slow / rapid mechanism is unnecessary. There is a possibility. In addition, since quartz and silicon have better temperature characteristics than metal, they are characterized by being less likely to deform with respect to ambient temperature than metal.

  However, since quartz and silicon are brittle materials, the balance spring using quartz and silicon has a problem in impact resistance, and there are also known problems such as deformation when the balance spring is operated for a long time. In order to solve the problem of the hairspring due to such crystal or silicon, a proposal has been made to increase the strength of the hairspring by forming a conductive material layer made of metal or the like on the surface of the hairspring (for example, (See Patent Document 1).

  The hairspring shown in Patent Document 1 is formed by forming a conductive material layer such as gold, platinum, rhodium, etc. on all or a part of the surface thereof, thereby increasing the mechanical strength of the hairspring and deforming it. It has been shown that it can be prevented.

  In addition, as described above, the balance spring of quartz or silicon has less variation in processing accuracy than the balance spring of general metal, but strictly speaking, there is variation in processing due to etching, so as to increase the accuracy of the rate of the watch. However, it is necessary to adjust the rate even if the balance spring is made of quartz or silicon.

  The rate adjustment of the balance spring with crystal or silicon can be realized by changing the Young's modulus of the balance spring by some method. As in Patent Document 1 presented as a conventional example, the conductive material layer is applied to the balance spring. Since the Young's modulus can also be changed by forming a film, it can be used as a means for adjusting the rate.

JP 2007-256290 A (page 4, FIG. 2)

  However, in the rate adjusting means to which Patent Document 1 is applied, the work process for forming the conductive material layer on the hairspring becomes indispensable, so that the manufacturing process of the hairspring becomes complicated and a large problem arises in mass productivity. In addition, in order to change the Young's modulus to a predetermined value by forming a conductive material layer on the surface of the hairspring, it is necessary to finely control the thickness of the film, which makes it difficult to control the thickness of the film. At the same time, there is a problem in accuracy of rate adjustment.

  An object of the present invention is to solve the above-mentioned problems and to provide a method for manufacturing a hairspring that can easily adjust the rate of the hairspring made of a crystal material with high accuracy.

  In order to solve the above-described problems, the following method is employed as the method for manufacturing the hairspring of the present invention.

  The method of manufacturing a hairspring of the present invention includes a ball having a through hole for fitting with a rotating shaft body, a coil connected to the ball and the connecting portion at a connection portion, and wound around the hair ball around the through hole. A method of manufacturing a hairspring, which is obtained by processing a material having a predetermined crystal structure, and a rate measuring step for measuring a rate, and a laser is applied to a predetermined region of the mainspring portion. And a laser irradiation step of irradiating.

  Thereby, since the rate of the hairspring formed by processing the material having a crystal structure is adjusted by laser irradiation, it is possible to provide a method for manufacturing the hairspring that can easily adjust the rate with high accuracy. In addition, since a slow / rapid mechanism for adjusting the rate of the hairspring is not necessary, it is possible to manufacture a hairspring that is resistant to impact and suitable for downsizing.

  The part of the predetermined region may be a region facing the connecting portion with the through hole of the whisker ball interposed therebetween.

  Depending on the shape and material of the hairspring, there is a region suitable for being non-crystallized or crystallized by laser irradiation.

  In the laser irradiation process, the crystal structure of a predetermined region may be changed to amorphous or crystalline based on the measurement result of the rate measurement process.

As a result, based on the measurement result of the rate measurement, the predetermined ratio of the mainspring portion is changed to amorphous or crystalline to change the Young's modulus and adjust the rate of the balance spring, so that the rate adjusted with a high accuracy is adjusted. The mainspring can be manufactured.

  In the laser irradiation step, at least one of laser output, depth of focus, irradiation range, irradiation frequency, and irradiation angle may be controlled.

  Thus, by controlling various parameters of the laser irradiating the hairspring, the hairspring can be made amorphous or crystallized with high accuracy, so that the rate of the hairspring can be finely adjusted.

  Moreover, you may make it a laser irradiation process irradiate a femtosecond laser.

  As a result, the specific region of the thin and small hairspring can be amorphized or crystallized with high accuracy, so that it is possible to realize a highly accurate rate adjustment of the hairspring.

  In the rate measuring step, the hairspring may be vibrated and the rate may be measured from the vibration state.

  As a result, it is possible to measure the rate of individual balance springs formed on the wafer in the wafer state, and based on the measurement data, the individual balance springs formed on the wafer are collectively irradiated with the laser. As a result, it is possible to manufacture a hairspring whose rate is adjusted with high accuracy without separating it from the wafer, and it is possible to manufacture a highly accurate hairspring that is easy to handle and has excellent mass productivity.

  In the rate measuring step, the hairspring may be incorporated in the drive mechanism, and the rate may be measured by extending and retracting the hairspring.

  As a result, the rate measurement is performed after the hairspring is incorporated into the drive mechanism, and laser irradiation is performed on the hairspring that is incorporated based on the measurement data, so that the influence of the drive mechanism is absorbed. The rate adjustment can be realized.

  Further, after the laser irradiation in the laser irradiation process, a wet etching process may be provided in which the hairspring is immersed in a predetermined etching solution for etching.

  As a result, the region in which the spring becomes amorphous by the laser irradiation loses anisotropy, so that the amorphous region is isotropically etched by performing the wet etching process after the laser irradiation. As a result, the amount of etching in the amorphized region is increased and the cross-sectional area is reduced, so that the Young's modulus can be reduced. As a result, by adjusting the etching time of wet etching, the Young's modulus can be changed and the rate of the hairspring can be adjusted.

  Further, the mainspring portion may be provided with a protective film forming step for forming a protective film having a crystal structure different from that of the mainspring and a trimming step for partially removing the protective film.

  Thus, by forming a protective film on the mainspring part, the rate of the balance spring is changed, and by partially trimming the protective film, the rate is changed in a direction to return to the state before the protective film is formed. Can be adjusted.

According to the method of manufacturing the hairspring of the present invention, the rate can be adjusted by laser irradiation after the hairspring is incorporated into the drive mechanism, so that it is highly accurate to absorb the influence of variations in the drive mechanism for each drive mechanism. It is possible to provide a method for manufacturing a hairspring that achieves rate adjustment.

  By using laser irradiation, the Young's modulus is changed by partially amorphizing or crystallizing the hairspring without scattering the balance of the hairspring material to the surroundings. it can.

  Further, it is possible to measure the yield of a large number of hairsprings formed on the wafer in a batch for each wafer and adjust the yield by laser irradiation in a batch for each wafer. As a result, it is possible to manufacture a large amount of the hairspring that has been adjusted in rate with high accuracy in the form of a wafer in a lump, and it is possible to realize the manufacture of a hairspring that is excellent in mass productivity.

It is a flowchart explaining the procedure of the manufacturing method of the hairspring concerning the 1st Embodiment of this invention. It is the top view and side sectional view showing an example of the hairspring concerning the 1st embodiment of the present invention. It is process drawing explaining the hairspring manufacturing process in the case of manufacturing the hairspring concerning the 1st Embodiment of this invention with a crystal | crystallization. It is process drawing explaining the mainspring manufacturing process in the case of manufacturing the mainspring concerning the 1st Embodiment of this invention with a silicon | silicone. It is explanatory drawing explaining the incorporating process and the rate measurement process which incorporate the hairspring concerning the 1st Embodiment of this invention in a drive mechanism. It is explanatory drawing explaining the laser irradiation process of the hairspring concerning the 1st Embodiment of this invention. It is an expanded sectional view explaining the amorphization by the laser irradiation of the hairspring concerning the 1st Embodiment of this invention. It is a flowchart explaining the procedure of the manufacturing method of the hairspring concerning the 2nd Embodiment of this invention. It is explanatory drawing explaining the rate measurement process and laser irradiation process of the hairspring on the wafer concerning the 2nd Embodiment of this invention. It is a flowchart explaining the procedure of the manufacturing method of the hairspring concerning the modification of the 2nd Embodiment of this invention. It is a flowchart explaining the procedure of the manufacturing method of the hairspring concerning the 3rd Embodiment of this invention. It is an expanded sectional view of the hairspring explaining the wet etching process concerning the 3rd Embodiment of the present invention. It is a flowchart explaining the procedure of the manufacturing method of the hairspring concerning the 4th Embodiment of this invention. It is a top view of the hairspring explaining the protective film formation process and trimming process concerning the 4th Embodiment of this invention. It is process drawing explaining the hairspring manufacturing process in the case of manufacturing the hairspring concerning the 5th Embodiment of this invention with a polycrystalline silicon. It is an expanded sectional view explaining crystallization by the laser irradiation of the hairspring concerning the 5th Embodiment of this invention.

Hereinafter, specific embodiments of the method for manufacturing a hairspring of the present invention will be described in detail with reference to the drawings. In the description, the hairspring will be described by taking as an example the case of an integral structure formed from a wafer made of a material having a crystal structure. In the description, the first to fourth embodiments are
The case where a material (crystal or single crystal silicon) having a crystalline structure is used is taken as an example. The fifth embodiment exemplifies a case where a material (amorphous silicon or polysilicon) having an amorphous crystal structure is used.

[Features of the embodiment]
The feature of the first to fourth embodiments is that the rate is adjusted by making the crystal amorphous by laser irradiation.
1st Embodiment demonstrates the manufacturing method of the hairspring which adjusts a rate by the laser irradiation of the hairspring in the state integrated in the drive mechanism.
In the second embodiment, a method for manufacturing a hairspring will be described in which the rate of the hairspring in a wafer state is adjusted collectively by laser irradiation.
In the third embodiment, a method for manufacturing a hairspring in which the rate is adjusted by etching after the laser irradiation process will be described.
In the fourth embodiment, a method for manufacturing a hairspring in which the rate is adjusted by trimming after forming the protective film will be described.
The feature of the fifth embodiment is that the rate is adjusted by crystallizing from amorphous by laser irradiation.

[Description of Manufacturing Process of Hairspring of First Embodiment: FIG. 1]
The steps of the hairspring manufacturing method according to the first embodiment will be described with reference to the flowchart of FIG. Details of each process will be described later. In addition, as a premise for explanation, the method for manufacturing the hairspring of the present embodiment exemplifies a manufacturing method in which a plurality of hairsprings are formed on a single wafer having a crystal structure and are collectively manufactured as a collection of hairsprings. Needless to say, the present embodiment is not limited to collective manufacturing by an assembly as a wafer, and the present embodiment can be applied to a manufacturing method in which one hairspring is formed on one wafer.

  In the flowchart of FIG. 1, first, the outer shape of a large number of hairsprings is formed on a plate-shaped wafer made of a material having a crystal structure using an etching technique (outer shape forming step: ST1).

  Next, the hairspring is individually separated from the wafer and incorporated into a drive mechanism (for example, a timepiece mechanism) (incorporation step: ST2).

  Next, the rate is measured by expanding and contracting the hairspring incorporated in the drive mechanism, and the rate measurement data is acquired (the rate measurement step: ST3).

Next, it is determined whether or not the acquired rate measurement data is within a predetermined reference value (determination step: ST4).
Here, if the determination is affirmative (within the reference value), the adjustment process is unnecessary, so the manufacturing process is terminated. If the determination is negative (out of the reference value), the process proceeds to step ST5.

  Next, if the determination step (ST4) is a negative determination, a laser irradiation condition for performing rate adjustment by laser irradiation is calculated based on the acquired rate measurement data (irradiation condition calculation step: ST5).

  Next, based on the irradiation condition calculated in the irradiation condition calculation step (ST5), the hairspring is irradiated with laser, a predetermined portion of the hairspring is changed to amorphous to change the Young's modulus, and The rate is adjusted (laser irradiation step: ST6).

  Next, returning to the rate measurement step (ST3), the rate of the hairspring is measured again, and steps ST3 to ST6 are repeated until an affirmative determination is made in the next determination step (ST4). In addition, in order to simplify a manufacturing process, you may complete | finish a manufacturing process by one laser irradiation process (ST6) (it shows with a broken line).

[Description of the shape of the hairspring of the first embodiment: FIG. 2]
Next, an example of the hairspring manufactured in the first embodiment will be described with reference to FIG.
Here, FIG. 2B is a sectional side view taken along the cutting line AA ′ shown in FIG. In FIG. 2, reference numeral 10 denotes a hairspring manufactured in the first embodiment. The hairspring 10 is integrally formed by a thin coil-shaped mainspring portion 11, a hairball 12 positioned at the center of the mainspring portion 11, and a beard 13 positioned at the end of the mainspring portion 11.

  The whisker ball 12 has a through hole 12a that fits into a rotating shaft (described later). In addition, the hairball 12 and the mainspring portion 11 are connected by a connection portion 12b. That is, the mainspring portion 11 is formed by winding the beard ball 12 around the beard ball 12 via the connection portion 12b. Further, the whisker 13 is provided with a through hole 13a that fits with a whisker pin (not shown).

  Here, the hairspring 10 is an integral structure formed from a wafer having a crystal structure, for example, quartz or single crystal silicon. The size of the hairspring 10 is not particularly limited. As an example of the size, when the thickness of the mainspring portion 11 is t and the width is w, the thickness t = 100 to 200 μm and the width w = 20. It is about ˜50 μm, and the approximate diameter is in the range of about 4 to 7 mm.

[Description of the outer diameter forming step (crystal) of the hairspring of the first embodiment: FIG. 3]
Next, the outer diameter forming step (ST1) of the hairspring of the first embodiment will be described with reference to FIG. 3 by taking the case where the crystal material is quartz as an example.
FIG. 3 is a cross-sectional view schematically showing a part of the cross section of the mainspring portion 11 of the hairspring 10 formed on the quartz wafer.

In FIG. 3, both surfaces of a crystal wafer 1 which is a flat single crystal plate adjusted to a predetermined plate thickness shown in FIG. 3A are resistant to an etching solution as shown in FIG. 3B. The metal corrosion resistant films 2a and 2b having the photoresist and the photoresists 3a and 3b are formed thereon.
These metal corrosion resistant films 2a and 2b can be formed using a known vapor deposition technique or sputtering technique. The photoresists 3a and 3b can be formed using a known spin coating technique.

  Next, as shown in FIG. 3C, two photomasks 4a and 4b each having a hairspring pattern drawn thereon are arranged above and below the crystal wafer 1, and a predetermined wavelength is applied from above the photomasks 4a and 4b. Are exposed to light (arrow B) to expose the photoresists 3a and 3b.

  Next, as shown in FIG. 3D, the photoresists 3a and 3b are developed, and the metal corrosion resistant films 2a and 2b are patterned using the formed resist pattern as a mask, and an etching mask which is an etching resistant mask member is formed. Form. This etching mask is denoted by reference numerals 5a and 5b.

  Next, as shown in FIG. 3 (e), after removing the photoresists 3a and 3b, the crystal wafer 1 having the etching masks 5a and 5b formed on both the front and back surfaces is subjected to a hydrofluoric acid-based etching solution which is a crystal etching solution When immersed in (not shown), the portion of the quartz not covered with the etching masks 5a and 5b is dissolved from both sides.

Thereafter, by removing the etching masks 5a and 5b, the mainspring portion 11 (that is, the hairspring 10) made of quartz is formed.
In the example shown in FIG. 3, only the cross section of the mainspring portion 11 is shown, but in reality, the entire outer shape of the hairspring 10 shown in FIG. 2 is formed by this outer shape forming step ST1.

[Description of the outer diameter forming step (silicon) of the hairspring of the first embodiment: FIG. 4]
Next, the outer diameter forming step (ST1) of the hairspring of the first embodiment will be described using FIG. 4 as an example in which the crystal material is single crystal silicon.
Here, FIG. 4 is a cross-sectional view schematically showing a part of the cross section of the mainspring 11 of the hairspring 10 formed on the silicon wafer. In addition, the outer diameter forming process of the hairspring by single crystal silicon can use a dry etching technique capable of etching with a high aspect ratio such as a deep RIE (Deep Reactive Ion Etching) technique. This is a known manufacturing technique similar to the manufacturing of a semiconductor circuit.

In FIG. 4, as shown in FIG. 4A, a SiO ₂ layer 21 that functions as a stopper when etching is performed by a deep RIE technique on a silicon wafer 20 that is a base, and a known film formation technique or oxidation technique. Further, an Si layer 22 (active layer) that becomes a hairspring is formed thereon by a known film formation technique.

  Of course, an SOI substrate having an oxide film layer above the silicon layer serving as a base and further having a silicon layer thereon may be used.

  Next, as shown in FIG. 4B, a photoresist is applied to the surface of the Si layer 22, and a mask 23 based on the shape of the hairspring is formed by photolithography.

Next, as shown in FIG. 4C, the Si layer 22 is deep-digged and dry-etched by the RIE technique using a mixed gas (SF ₆ + C ₄ F ₈ ) (arrow G). Thereby, the outer shape of the hairspring 10 is formed on the silicon wafer 20.

Next, as shown in FIG. 4D, the mask 23 is removed, and further, as shown in FIG. 4E, the SiO ₂ layer 21 is removed by hydrofluoric acid (not shown), whereby the Si layer 22 is cut off, and the mainspring portion 11 (ie, the hairspring 10) is formed of single crystal silicon.

  The method for manufacturing the hairspring when the crystal material is crystal and single crystal silicon has been described above. In the following description, description will be made on the premise of a hairspring formed from a quartz wafer.

[Explanation of the hairspring incorporation process of the first embodiment: FIG. 5]
Next, the hairspring main step incorporating step (ST2) of the first embodiment will be described with reference to FIG. Note that, as a premise of the description, the drive mechanism incorporating the hairspring is assumed to be a mechanical timepiece. In FIG. 5, the hairspring 10 is incorporated in a drive mechanism 40 (mechanical timepiece) as a balance 30 that is a speed adjusting mechanism together with a balance 31 and a balance wheel 32 that are rotating shaft bodies.

  That is, the balance 31 is fitted in the through hole 12 a (see FIG. 2) formed in the hair ball 12 of the hairspring 10, and the balance 30 integrated with the balance wheel 32 is incorporated in the drive mechanism 40. Here, as is well known, the balance 30 performs a reciprocating motion excellent in isochronism by the expansion and contraction motion of the hairspring 10 and functions as the heart of the drive mechanism 40.

Further, the drive mechanism 40 has a power mainspring (not shown) included in the barrel complete 46 as a driving force to transmit the rotational force to the second wheel 45, the third wheel 44, and the fourth wheel 43 and each number. The car is rotated at a predetermined speed. A escape wheel 42 is engaged with the fourth wheel 43 and an ankle 41 is engaged with the escape wheel 42. The escape wheel 42, the ankle 41, and the balance 30 constitute a speed control mechanism that converts the reciprocating motion of the balance 30 into a rotational motion.

  A second hand 47 is attached to the fourth wheel 43 and a minute hand 48 is attached to the second wheel 45. Note that the hour hand and the ground plate for supporting each gear are not shown.

  Here, as described above, the balance 30 is transmitted with the driving force from the barrel complete 46 and regularly operates by the expansion and contraction motion of the spring mainspring 10 by the spring force. The expansion and contraction movement of the hairspring 10, that is, the regularity of the reciprocating movement of the balance 30, is based on the rate of the hairspring 10, and the advance / delay of the timepiece is determined by the rate of the hairspring 10.

[Explanation of the rate measurement process of the hairspring of the first embodiment: FIG. 5]
Next, the rate measuring step (ST3) of the hairspring of the first embodiment will be described with reference to FIG. In FIG. 5, as described above, the hairspring 10 is incorporated in the drive mechanism 40 and continues to expand and contract by the driving force of the barrel complete 46. In the rate measuring step, the rate is measured using a rate measuring device (not shown) that detects the expansion and contraction movement of the balance spring 10, that is, the reciprocating movement of the balance 30 with a special voice microphone.

  As this rate measuring device, a general measuring device used for maintenance of a mechanical timepiece can be used. That is, in the step of measuring the rate of the hairspring of the first embodiment, the rate of the hairspring 10 is measured in a state where it is incorporated in the drive mechanism 40.

[Explanation of irradiation condition calculation step (ST5) of hairspring of the first embodiment]
Next, an irradiation condition calculation step (ST5) performed when the rate measurement data acquired in the rate measurement step (ST3) does not fall within a predetermined reference value (negative determination in determination step ST4) will be described. Here, since the rate measurement data is outside the reference value, the irradiation condition of the laser for irradiating the hairspring is calculated from the rate measurement data.

  The laser used here is a known femtosecond laser, and the laser irradiation conditions include at least one of laser output, depth of focus, irradiation range, irradiation frequency, and irradiation angle in the rate measurement process. An irradiation condition is calculated based on the obtained rate measurement data, and laser irradiation is controlled. The irradiation condition calculation work is preferably automatically performed by a computer or the like, but is not limited thereto. Further, the laser is not limited to a femtosecond laser as long as the same effect is exhibited.

[Description of Laser Spring Step (ST6) of Hairspring of First Embodiment: FIG. 6]
Next, the laser irradiation process (ST6) of 1st Embodiment is demonstrated using FIG. 6B is a side cross-sectional view taken along the cutting line AA ′ shown in FIG. 6A, similarly to FIG. 2 described above. In FIG. 6, in the laser irradiation step, the femtosecond laser 51 is irradiated from the laser irradiator 50 to the hairspring 10 incorporated in the drive mechanism 40 based on the irradiation conditions obtained in the above-described irradiation condition calculation step. (See FIG. 6B).

FIG. 6A shows an example of an irradiation region E (indicated by hatching) in which the rate can be adjusted effectively by irradiation with the femtosecond laser 51. As shown in the figure, it is particularly effective for adjusting the rate when the femtosecond laser 51 is irradiated to a predetermined region of the mainspring portion 11 that sandwiches the through hole 12a of the whistle ball 12 and faces the connecting portion 12b. It became clear by experiment etc. Here, when the irradiation area E is expressed by an angle θ with the through hole 12a of the whistle ball 12 as the center, the angle θ of the irradiation area E effective for the rate adjustment is 180 degrees or less, preferably about 90 degrees. .
Note that the optimum irradiation region E may vary depending on the material and shape of the hairspring, so it is preferable to know in advance through experiments or the like.

  Here, the reason why the rate of the hairspring 10 can be adjusted by laser irradiation is that when the mainspring portion 11 of the hairspring 10 is irradiated with the femtosecond laser 51, the irradiation region E of the mainspring portion 11 is heated by the laser irradiation and the crystal structure of the crystal. Changes to amorphous. That is, quartz is modified into quartz glass. Here, although the Young's modulus of quartz is about 97, the Young's modulus of quartz glass is about 72. Therefore, the Young's modulus is reduced by making the irradiation region E amorphous, and as a result, the hairspring 10 The rate can be adjusted (specifically, the rate can be slowed down).

  Further, by making the irradiation region E shown in FIG. 6A amorphous, the balance of expansion and contraction of the hairspring 10 becomes good, and the balance spring with excellent isochronism can be obtained together with the adjustment of the rate. it can.

  In addition, it is not necessary to make all the thin coil-shaped mainspring portions 11 constituting the hairspring 10 in the irradiation region E amorphous. It suffices to determine which part of the mainspring portion 11 is to be modified based on the Young's modulus of the hairspring 10.

  Even when the material of the hairspring 10 is single crystal silicon, it is modified to amorphous silicon by irradiation with the femtosecond laser and the Young's modulus is lowered, so that the rate can be adjusted similarly.

[Description of Amorphization by Laser Irradiation of Hairspring of First Embodiment: FIG. 7]
Next, an example of how the mainspring portion 11 is amorphized by irradiating the mainspring portion 11 of the hairspring 10 with the femtosecond laser 51 in the laser irradiation step (ST6) is shown in FIG. Will be described.

  Here, FIG. 7 is a side sectional view of the mainspring portion 11 in which a part of FIG. 6B is enlarged, and FIG. 7A illustrates the case where the irradiation of the femtosecond laser 51 is weak. The amorphous region 11b of the mainspring portion 11 to be irradiated is partially formed inside the mainspring portion 11 as shown in the drawing. The periphery other than the amorphous region 11b is the crystal region 11a.

  FIG. 7B illustrates the case where the intensity of the femtosecond laser 51 is medium. The amorphous region 11c of the mainspring portion 11 to be irradiated is shown in FIG. Formed in most of the interior.

  FIG. 7C illustrates a case where the irradiation of the femtosecond laser 51 is strong, and the amorphous region 11d of the mainspring portion 11 to be irradiated is present throughout the mainspring portion 11 as illustrated. It is formed.

  Here, the strength of the femtosecond laser 51 is implemented by calculating and controlling the irradiation condition based on the measurement result of the rate of at least one of the laser output, the irradiation frequency, and the irradiation angle. That is, by changing at least one condition of laser output, irradiation frequency, and irradiation angle, the amount of energy per unit time irradiated to the mainspring portion 11 can be changed, and the range of the amorphous region can be changed, The Young's modulus of the hairspring can be adjusted.

That is, as shown in FIG. 7 (a), if the amorphous region 11b is formed in a small region inside the mainspring portion 11, the Young's modulus decreases little, so the change (decrease) in the rate is small. Become. Further, as shown in FIG. 7C, if the amorphous region 11d is formed in the whole mainspring portion 11, the Young's modulus is greatly decreased, and the rate change (decrease) is also increased. Therefore, the adjustment range of the rate can be expanded.

  Further, by changing the irradiation range of the femtosecond laser 51, the rate can be adjusted by changing the range and position of the irradiation region. That is, as described above with reference to FIG. 6A, changing the angle θ of the irradiation region E that is effective for adjusting the rate (that is, changing the irradiation range) changes the Young's modulus of the hairspring 10 to change the rate. Can be adjusted. For example, if the angle θ is reduced to narrow the irradiation area E, the change in the Young's modulus of the hairspring 10 is reduced, so that the adjustment range of the rate by laser irradiation is reduced. Further, if the angle θ is increased to widen the irradiation region E, the change in the Young's modulus of the hairspring 10 increases, so that the rate adjustment range can be increased.

  Further, the rate can be adjusted by changing the focal depth of the femtosecond laser 51. That is, by adjusting the focal depth of the femtosecond laser 51 and condensing the femtosecond laser 51 near the center C of the cross section of the mainspring portion 11 as shown in FIG. The amount of energy per hit can be increased, and the mainspring portion 11 can be reliably amorphized. As described above, the femtosecond laser 51 can be made amorphous even if it is made of a transparent material such as quartz by condensing. Therefore, the femtosecond laser 51 is suitable for adjusting the rate of the balance spring with quartz.

  As described above, according to the method of manufacturing the hairspring according to the first embodiment, the rate of the hairspring can be finely adjusted with high accuracy by laser irradiation after the hairspring is incorporated into a drive mechanism (for example, a watch). Absorbing not only the variation in the mainspring's machining but also the variation in the machining accuracy of the drive mechanism and the variation in assembly accuracy, it is possible to achieve highly accurate rate adjustment according to the individual drive mechanism, and the effect is extremely high large.

  In addition, the rate adjustment is not performed by polishing the hairspring 10 or adjusting the rate by changing the Young's modulus by making the inside of the hairspring 10 amorphous by irradiation of the femtosecond laser. No residue is scattered around, no problem occurs even when the rate is adjusted by incorporating it in a small and precise drive mechanism, and a method for manufacturing a hairspring with excellent reliability can be provided. .

  Further, since the balance of expansion and contraction of the hairspring 10 can be improved by irradiation with the femtosecond laser, it is possible to manufacture a hairspring having excellent isochronism. By adopting this hairspring in a mechanical timepiece, It also has the effect of improving the position difference of the timepiece.

[Description of Manufacturing Process of Hairspring of Second Embodiment: FIG. 8]
Next, the steps of the hairspring manufacturing method according to the second embodiment will be described with reference to the flowchart of FIG. Details of each process will be described later. Here, in the method of manufacturing the hairspring of the second embodiment, a plurality of hairsprings are formed on a single wafer having a crystal structure, the hairsprings are manufactured collectively as a collection of hairsprings, and the rate measurement is extracted. It is a manufacturing method implemented by.

In the flowchart of FIG. 8, first, the outer shape of a large number of hairsprings is formed on a wafer of a material having a crystal structure using an etching technique (outer shape forming step: ST10). Since this outer shape forming step (ST10) is the same as the outer shape forming step (ST1: see FIGS. 3 and 4) of the hairspring of the first embodiment described above, detailed description thereof is omitted. In the following description, the description will be made on the assumption that the hairspring is made of crystal, and the hairspring formed in this outer shape forming step (ST10) is the same as the shape of the hairspring 10 of the first embodiment (see FIG. 2). It is.

  Next, the quartz wafer 1 on which a large number of hairsprings 10 are formed is placed on the rate measuring system, and the vibration frequency of the quartz wafer 1 is extracted by the vibration measuring instrument while vibrating the quartz wafer 1. (Sampling rate measuring step: ST11).

  Next, the rate measurement data obtained in the sampling rate measurement step (ST11) is averaged, and the average value of the rates of the large number of hairsprings 10 formed on the measured quartz wafer 1 is calculated (average value calculation step: ST12). ).

  Next, it is determined whether or not the calculated average rate is within a predetermined reference value (determination step: ST13). Here, if the determination is affirmative (within the reference value), the adjustment process is unnecessary, so the manufacturing process is terminated. If the determination is negative (outside the reference value), the process proceeds to step ST14.

  Next, if a negative determination is made in the determination step ST13, a laser irradiation condition for performing rate adjustment by laser irradiation is calculated (irradiation condition calculation step: ST14). Here, as in the first embodiment, as the laser irradiation conditions, at least one of the laser output, the focal depth, the irradiation range, the irradiation frequency, and the irradiation angle is obtained in the sampling rate measurement step (ST11). Irradiation conditions are calculated based on the measured rate measurement data. The irradiation condition calculated here is applied to all the hairsprings 10 on the crystal wafer 1.

  Next, based on the irradiation condition calculated by the irradiation condition calculation step, the femtosecond laser is irradiated to the total number of the hairsprings 10 formed on the crystal wafer 1, and a predetermined portion of the hairspring 10 is made amorphous. The Young's modulus is changed to change the rate of the hairspring 10 (laser irradiation step: ST15).

  Next, returning to the sampling rate measurement step (ST11), the rate of the hairspring 10 is measured again, and steps ST11 to ST15 are repeated until an affirmative determination is made in the determination step (ST13). In addition, in order to simplify a manufacturing process, you may complete | finish a manufacturing process by one laser irradiation process (ST15) (it shows with a broken line). Further, when the rate of the hairspring 10 does not reach the reference value in the manufacturing process of the present embodiment, additional rate adjustment may be performed according to a third embodiment (see FIG. 11) described later.

[Explanation of Step of Measuring Balance Rate of Second Embodiment: FIG. 9]
Next, an example of the hairspring extraction rate measuring step (ST11) according to the second embodiment will be described with reference to FIG. In FIG. 9, the quartz wafer 1 on which a large number of hairsprings 10 are formed is placed on a stage 61 included in the rate measuring system 60, and the stage 61 is vibrated, whereby all of the hairsprings 10 on the quartz wafer 1 are predetermined. Vibrate at a frequency of. Here, the stage 61 is driven by the drive unit 62 of the rate measurement system 60, and the drive unit 62 is controlled by the control unit 63 to control the vibration to the crystal wafer 1.

  When vibration from the stage 61 is applied to the quartz wafer 1, the individual balance springs 10 formed on the quartz wafer 1 vibrate simultaneously at their natural frequencies. Note that, for the sake of convenience, four hairsprings 10 on the crystal wafer 1 are illustrated, but in reality, a large number of hairsprings are formed. The means for vibrating the hairspring 10 on the quartz wafer 1 is not limited, and a large number of hairsprings 10 may be sequentially vibrated one by one by means not shown.

Next, the vibration measurement system 60 includes, as an example, a laser Doppler vibration measurement device 64,
A predetermined laser beam 65 is irradiated onto the hairspring 10 on the crystal wafer 1 and its vibration state is measured, and the control unit 63 stores it as rate measurement data.

  Here, the rate measurement employs a sampling method in which a large number of hairsprings 10 on the crystal wafer 1 are selected and measured at a predetermined ratio at random. This makes it possible to reduce the time for measuring the rate. In order to measure the rate of an arbitrary hairspring 10 on the quartz wafer 1, a moving means for moving the laser Doppler vibration measuring device 64 relative to each hairspring 10 on the quartz wafer 1 is necessary. .

  As the moving means, the laser Doppler vibration measuring instrument 64 is fixed by means not shown, and the stage 61 is moved in the X direction or Y direction by means not shown, so that any balance spring 10 on the crystal wafer 1 is laser This can be realized by controlling to be directly under the Doppler vibration measuring device 64. As another means, the stage 61 may be fixed and the laser Doppler vibration measuring instrument 64 may be moved in the X direction or the Y direction by means not shown.

[Description of Laser Spring Process of Hairspring of Second Embodiment: FIG. 9]
Next, an example of the laser irradiation process (ST15) of the second embodiment will be described with reference to FIG. The basic configuration of the laser irradiation system 70 used in the laser irradiation step (ST15) is a configuration close to the above-described rate measurement system 60 (see FIG. 9). The laser irradiation system 70 includes a laser Doppler vibration measuring device 64. This can be realized by changing to the laser irradiation device 50 and changing the rate measurement software of the control unit 63 to the laser irradiation software. Therefore, the laser irradiation step (ST15) will be described with reference to FIG. 9 for explaining the sampling rate measurement step (ST11) described above, and the same reference numerals are used for common elements of the system.

  In FIG. 9, in the laser irradiation step (ST15), the femtosecond laser 51 from the laser irradiator 50 is applied to all the hairsprings 10 on the crystal wafer 1 based on the irradiation conditions obtained in the irradiation condition calculation step (ST14). Irradiation is performed to make a predetermined region of the mainspring portion 11 amorphous to lower the Young's modulus and adjust the rate of the hairspring 10. Note that the intensity control of the femtosecond laser 51, the irradiation region determination, and the like are the same as those in the first embodiment described above, and thus the description thereof is omitted here.

  Further, the means for moving the laser irradiator 50 relative to each hairspring 10 of the crystal wafer 1 is the same as the moving means of the rate measuring system 60 described above, and the description thereof is omitted. Although the description has been given on the assumption that a large number of the hairsprings 10 are formed on the crystal wafer 1, the rate adjustment may be performed by forming one hairspring on one crystal wafer. Alternatively, each hairspring 10 may be separated from the crystal wafer 1, the rate of each hairspring 10 may be measured, and the rate may be adjusted by laser irradiation.

  As described above, according to the method of manufacturing the hairspring according to the second embodiment, the rate of the hairsprings formed on the wafer in a wafer state is collectively measured in the wafer state, and the wafer state is maintained based on the measurement data. Since the rate adjustment by laser irradiation is performed collectively, it is possible to provide a highly accurate hairspring manufacturing method that is easy to handle and excellent in workability and mass productivity. Further, since the rate measurement is performed by extracting a large number of hairsprings on the wafer, the rate measurement time can be greatly shortened, and a method for manufacturing a hairspring having excellent work efficiency can be realized.

[Description of Manufacturing Process of Hairspring of Modified Example of Second Embodiment: FIG. 10]
Next, the steps of the hairspring manufacturing method according to the modification of the second embodiment will be described with reference to the flowchart of FIG. Here, in the method of manufacturing the hairspring of the modified example of the second embodiment, a plurality of hairsprings are formed on a single wafer having a crystal structure, the hairsprings are collectively manufactured, and the rate is The measurement is a manufacturing method performed for all the hairsprings on the wafer.

  In the flowchart of FIG. 10, first, the outer shape of a large number of hairsprings is formed on a wafer of a material having a crystal structure by using an etching technique (outer shape forming step: ST20). Since the outer shape forming step (ST20) is the same as the outer shape forming step (ST1: see FIGS. 3 and 4) of the hairspring of the first embodiment described above, detailed description thereof is omitted. In the following description, description will be made on the premise of a hairspring by crystal, and the hairspring formed in this outer shape forming step (ST20) is the same as the shape of the hairspring 10 of the first embodiment (see FIG. 2). It is.

  Next, the quartz wafer 1 on which a large number of hairsprings 10 are formed is placed on the rate measuring system, and the quartz wafer 1 is vibrated while the quartz wafer 1 is vibrated. ) Are sequentially measured to obtain the rate measurement data, and stored together with the individual coordinate position data of the measured hairspring 10 (total rate measurement step: ST21). The total rate measurement step (ST21) is performed by the rate measurement system 60 (see FIG. 9) in the same manner as the sampling rate measurement step (ST11) according to the second embodiment described above, and detailed description thereof is omitted.

  Next, the rate measurement data and the coordinate position data acquired in the total rate measurement step (ST21) are individually read for each hairspring 10, and the rate measurement data and a predetermined reference value are compared (individual comparison step: ST22). ).

  Next, based on the comparison result of the rate measurement data of the hairspring 10 read out individually, it is determined whether the rate measurement data is within a predetermined reference value (determination step: ST23). Here, if the determination is affirmative (within the reference value), there is no need to irradiate the hairspring 10 with laser, and the process proceeds to step ST26. If the determination is negative (out of the reference value), the process proceeds to the next step ST24. move on.

  Next, when the determination step ST23 is negative, a laser irradiation condition for performing rate adjustment by laser irradiation is calculated (irradiation condition calculation step: ST24). Since this irradiation condition calculation step (ST24) is the same as the irradiation condition calculation step (ST14) of the second embodiment, description thereof is omitted.

  Next, on the basis of the irradiation condition calculated in the irradiation condition calculation step (ST24), the individual hairspring 10 formed on the quartz wafer 1 is irradiated with a femtosecond laser, and a predetermined portion of the hairspring 10 is not covered. The Young's modulus is changed by changing the crystal quality, and the rate of the hairspring 10 is adjusted (individual laser irradiation step: ST25).

  Since the individual laser irradiation step (ST25) is performed by the laser irradiation system 70 (see FIG. 9) used in the laser irradiation step (ST15) according to the second embodiment described above, detailed description thereof is omitted. Although it is necessary to move each hairspring 10 directly below the laser irradiator 50 (see FIG. 9), the hairspring 10 is referred to with reference to the coordinate data of each hairspring 10 read together with the rate measurement data. Control to move relatively.

  Next, it is determined whether the individual comparison step (ST22) has been performed for all the hairsprings 10 on the crystal wafer 1 (end determination step: ST26). Here, if the individual comparison process (ST22) is completed for all the hairsprings 10 (positive determination), the hairspring manufacturing process is completed, and if not completed (negative determination), the individual determination process ( Returning to ST22), steps ST22 to ST26 are repeated.

  As described above, according to the method for manufacturing the hairspring according to the modification of the second embodiment, the rate of the total number of hairsprings formed on the wafer is measured, and laser irradiation conditions are individually determined based on the measurement data. Since the rate adjustment by laser irradiation is performed, even if the balance rate of the balance spring varies within one wafer, the variation is absorbed and the balance spring adjusted with high accuracy is batched for each wafer. Can be manufactured. As a result, it is possible to provide a method for manufacturing a hairspring that is excellent in mass productivity and highly accurate.

[Description of Manufacturing Process of Hairspring of Third Embodiment: FIG. 11]
Next, the steps of the hairspring manufacturing method of the third embodiment will be described with reference to the flowchart of FIG. Here, the manufacturing method of the hairspring of the third embodiment is a manufacturing method suitable for adjusting the rate after performing the manufacturing method of the hairspring of the first or second embodiment described above. .

  In FIG. 11, the quartz wafer 1 on which a large number of hairsprings are formed is placed on the rate measuring system 60 (see FIG. 9), and the natural frequency (yield) of the hairspring 10 on the quartz wafer 1 is vibrated while the quartz wafer 1 is vibrated. Is measured by sampling (sampling rate measuring step: ST30).

  Next, the rate measurement data obtained in the sampling rate measurement step (ST30) is averaged, and the etching time for etching the crystal wafer 1 is calculated based on the rate averaged data (etching time calculation step: ST31). Here, if the rate adjustment width is large, the etching time is set long, and if the rate adjustment width is small, the etching time is set short.

  Next, the crystal wafer 1 is wet-etched based on the calculated etching time (wet etching step: ST32). Details of this wet etching step will be described later.

  Next, the crystal wafer 1 that has been subjected to the etching process is placed again on the rate measurement system 60 (see FIG. 9), and the rate of the hairspring 10 formed on the crystal wafer 1 is confirmed (rate check step: ST33). ).

  Next, it is determined whether or not the hairspring rate measured again is within a predetermined reference value (determination step: ST34). Here, if the determination is affirmative (within the reference value), the manufacturing process ends. If the determination is negative (out of the reference value), the process may return to step ST31 to perform etching again.

[Description of the hairspring of the third embodiment: FIG. 12]
Here, the crystal has a characteristic that the etching has anisotropy due to its crystal structure, and the etching rate varies depending on the direction of the crystal. That is, in general, when a Z-cut quartz wafer is used, the amount of cutting in the thickness direction (Z′-axis direction) is much larger than the lateral direction (X-axis direction). However, since the etching anisotropy is lost in the portion that has become amorphous due to the irradiation of the femtosecond laser, not only in the thickness direction (Z′-axis direction) but also in the lateral direction (X-axis direction). (Isotropic etching).

FIG. 12 is an enlarged cross-sectional view of a part of the mainspring portion 11 schematically illustrating a difference in etching depending on the presence or absence of laser irradiation when the hairspring 10 made of quartz is wet-etched for a predetermined time. FIG. 12A shows the etching state of the mainspring portion 11 when there is no irradiation of the femtosecond laser and the inside of the mainspring portion 11 is the crystal region 11a. The mainspring portion 11 is caused by the etching anisotropy described above. The thickness direction (Z′-axis direction) is greatly cut (the state before etching is indicated by a broken line), but the horizontal direction (X-axis direction) is hardly cut.

  On the other hand, FIG. 12B shows an etching state when the entire interior of the mainspring portion 11 becomes an amorphous region 11d by the irradiation of the femtosecond laser, and as a result of loss of etching anisotropy, It becomes isotropic etching, and the thickness direction (Z′-axis direction) and the lateral direction (X-axis direction) of the mainspring portion 11 are cut in the same way (the state before etching is indicated by a broken line).

  Accordingly, when the hairspring 10 whose irradiation region has become amorphous by the irradiation of the femtosecond laser is immersed in a predetermined etching solution and wet-etched for a predetermined time, the amorphous region 11d (FIG. 12B) Is larger than the crystal region 11a (FIG. 12A), and as a result, the cross-sectional area of the mainspring portion 11 whose entire interior is the amorphous region 11d is smaller than the cross-sectional area of the crystal region 11a (see FIG. That is, the amorphous region 11d becomes thinner.

  As a result, the Young's modulus of the amorphous region 11d becomes smaller than that before the etching, and as a result, the rate of the hairspring 10 decreases. Since the decrease in the yield due to this wet etching depends on the etching time, calculating the rate adjustment range from the rate measurement result, determining the etching time from this rate adjustment range, and performing the wet etching, the balance spring This rate can be adjusted by the difference in etching time.

  As described above, according to the method of manufacturing the hairspring according to the third embodiment, the yield can be adjusted by further changing the Young's modulus of the hairspring that has been adjusted in rate by irradiating the femtosecond laser, so that the Young's modulus can be adjusted. Additional adjustment of the rate of the hairspring is possible.

  The method of manufacturing the hairspring according to the third embodiment includes, for example, additional rate adjustment when the rate adjustment of the hairspring 10 does not reach the reference rate by the femtosecond laser irradiation according to the second embodiment. It is effective as a method. That is, by performing additional rate adjustment by wet etching according to the third embodiment on a crystal wafer that cannot be adjusted to the reference rate and is supposed to be defective, the defective wafer can be made non-defective, and the wafer yield can be improved. There is an effect that can be improved.

  Further, the hairspring manufacturing method according to the third embodiment may be implemented as a post-process of the first embodiment. That is, the hairspring 10 is incorporated into the drive mechanism 40 and the rate is adjusted by irradiation with the femtosecond laser. If the rate does not reach the reference value, the hairspring 10 is removed from the drive mechanism 40 and the third embodiment is performed. It is possible to adjust the rate and implement it again in the drive mechanism 40.

[Description of Manufacturing Process of Hairspring of Fourth Embodiment: FIG. 13]
Next, the steps of the hairspring manufacturing method of the fourth embodiment will be described with reference to the flowchart of FIG. Here, the manufacturing method of the hairspring of the fourth embodiment is a manufacturing method suitable for being implemented in combination with the manufacturing method of the hairspring of the first to third embodiments.

  In FIG. 13, a protective film having a crystal structure different from that of the hairspring 10 is formed on the surface of the hairspring 10 on the quartz wafer 1 (protective film forming step: ST40). Details of the protective film forming step will be described later.

Next, the crystal wafer 1 on which the protective film is formed is placed on the rate measurement system 60 (see FIG. 9), and the natural frequency (the rate) of the hairspring 10 on the crystal wafer 1 is measured to obtain rate measurement data. (Rate measurement step: ST41). In this rate measuring step (ST41), the balance spring 10 on the crystal wafer 1 may be measured by a sampling method, or the total rate may be measured. Here, the hairspring 10 having a protective film formed on the surface has a higher strength and a higher Young's modulus. Therefore, the rate of the hairspring is faster than that before the protective film is formed.

  Next, the trimming amount for trimming the protective film is calculated based on the rate measurement data obtained in the rate measuring step (ST41), and the protective film formed on the surface of the hairspring 10 is irradiated with a laser to apply the protective film. Trimming is performed (trimming step: ST42). Here, as the trimming apparatus, the laser irradiation system 70 (see FIG. 9) shown in the second embodiment can be used. By this trimming step (ST42), a part of the protective film formed on the surface of the hairspring 10 is removed, so that the Young's modulus of the hairspring 10 decreases according to the amount of the removed protective film, The rate is adjusted in the direction of slowing down.

  Next, the rate of the quartz wafer 1 for which the trimming step (ST42) has been completed is measured again, and the rate of the hairspring 10 is confirmed (a rate confirmation step: ST43).

  Next, it is determined whether or not the rate of the hairspring 10 measured again is within a predetermined reference value (determination step: ST44). Here, if the determination is affirmative (within the reference value), the manufacturing process ends, and if the determination is negative (out of the reference value), the process may return to step ST42 and trimming may be performed again.

  That is, in the fourth embodiment, by forming a protective film on the surface of the hairspring 10 to change the rate to increase the rate, and then trimming the protective film based on the rate measurement data, The rate is changed in the direction of slowing down and adjusted so that it falls within the range of the reference value.

[Description of the hairspring protective film forming process and trimming process of the fourth embodiment: FIG. 14]
Next, an example of the protective film forming process and the trimming process of the fourth embodiment will be described with reference to FIG. FIG. 14 is a plan view of the hairspring 10 in which the trimming process is performed after the protective film forming process. In FIG. 14, a metal as a protective film is formed on the entire surface of the mainspring portion 11 of the hairspring 10 in the protective film forming process (ST40). A film 15 (outlined portion) is formed.

  For example, the metal film 15 is a metal film in which chromium (Cr) is used as a base and gold (Au) is provided thereon. The metal film 15 can be formed using a known vapor deposition technique or sputtering technique. The metal film 15 is formed on the entire surface of the mainspring portion 11 of the hairspring 10, but is not particularly limited and may be formed partially.

  In a trimming step (ST42), a predetermined portion of the mainspring portion 11 is irradiated with a femtosecond laser (not shown) to form a trimming region 16 (black-filled portion) from which the metal film 15 is removed, and the rate is increased. Adjusted. That is, the femtosecond laser 51 is irradiated to the metal film 15 formed on the balance spring 10 from the laser irradiator 50 of the laser irradiation system 70 (see FIG. 9). Then, the portion of the metal film 15 irradiated with the femtosecond laser 51 is melted and scattered, and the trimming region 16 where the quartz base is exposed is formed.

  The range of the trimming region 16 is determined by how much the rate of the hairspring 10 is deviated from the reference value. That is, if the rate of the hairspring 10 is greatly deviated from the reference value, the trimming region 16 is set wide, and if the rate of the hairspring 10 is slightly deviated from the reference value, the trimming region 16 is set narrow.

As described above, according to the hairspring manufacturing method according to the fourth embodiment, the metal film 15 is formed on the surface of the hairspring 10, and a predetermined region of the metal film 15 is trimmed with a laser, whereby It becomes possible to adjust the rate by changing the Young's modulus of the mainspring 10.

  Here, when the metal film 15 is formed on the hairspring 10, the Young's modulus of the hairspring 10 is increased and the rate is increased. Therefore, the method of manufacturing the hairspring according to the fourth embodiment is based on the rate of the hairspring. This is effective as a rate adjustment method when the value becomes slower than the value. For example, although the rate adjustment is performed according to the second and third embodiments, the fourth embodiment is effective when the rate is adjusted too much and the rate exceeds the reference value and becomes slower than the reference value.

  Further, the hairspring manufacturing method according to the fourth embodiment may be implemented as a subsequent process of the first embodiment. That is, the hairspring 10 is incorporated into the drive mechanism 40 and the rate is adjusted by irradiation with the femtosecond laser. If the rate is slower than the reference value, the hairspring 10 is removed from the drive mechanism 40 and the fourth embodiment is performed. The embodiment may be implemented to adjust the rate, and may be incorporated into the drive mechanism 40 again.

  Further, the hairspring manufacturing method according to the fourth embodiment may be implemented as a pre-process for adjusting the rate by irradiation with a femtosecond laser. For example, after the outer shape forming process of each embodiment, the metal film 15 is formed in advance at a predetermined location, and the rate of the hairspring 10 is set faster than the reference value by trimming as necessary, and then the femtosecond by the laser irradiation process is set. Adjustment to delay the rate and match the reference value may be performed by making the laser amorphous.

  The hairspring manufacturing method according to the fourth embodiment can also be used as a rate adjusting means for adjusting the balance of the hairspring 10 by delaying the rate of the hairspring 10 by increasing the mass by forming the metal film 15 on the mainspring portion 11. Is possible. That is, by selecting the material of the metal film 15 formed on the mainspring portion 11 and selecting the thickness, trimming region, etc. of the metal film 15, the metal film 15 is formed so that the influence of mass is larger than the influence of Young's modulus. realizable.

  As described above, the method of manufacturing the hairspring according to the fourth embodiment is effective in that the rate adjustment of the hairspring 10 can be performed widely and finely by being combined with the rate adjustment by the irradiation of the femtosecond laser. . The laser for trimming the metal film 15 is not limited to the femtosecond laser.

[Description of the hairspring of the fifth embodiment: FIG. 15]
Next, as a fifth embodiment, a case where the crystal material is amorphous will be described as an example with reference to FIG. As the amorphous material, amorphous silicon or polysilicon can be used. In this embodiment, amorphous silicon will be described as an example.

The hairspring of the fifth embodiment is the same as the embodiment described above except that amorphous silicon is used as a crystal material and the rate is adjusted by laser irradiation. Accordingly, the procedure for manufacturing the hairspring and adjusting the rate is the same, and FIG. 1 is referred to for a flowchart showing the flow of processing.
First, the outer shape forming process of the hairspring 100 will be described. This step corresponds to the outer diameter forming step (ST1) of the first embodiment.

Here, FIG. 15 is a cross-sectional view schematically showing a part of the cross section of the mainspring 110 of the hairspring 100 formed on the silicon wafer. The hairspring 100 corresponds to the hairspring 10 shown in FIG. 2, and the mainspring portion 110 corresponds to the mainspring portion 11 shown in FIG. Accordingly, the outer shape is the same as that shown in FIG.

  The hairspring 100 of the present embodiment is made of amorphous silicon. In the outer diameter forming process of the hairspring 100, a dry etching technique capable of etching with a high aspect ratio can be used as in the other embodiments already described.

In FIG. 15, as shown in FIG. 15A, an SiO ₂ layer 210 that functions as a stopper when performing dry etching is formed on a base silicon wafer 20 by a known film formation technique or oxidation technique. Further thereon, an amorphous silicon layer 220 serving as a hairspring is formed by a known film forming technique.

  Since the amorphous silicon layer 220 is a part constituting the hairspring 100, it is formed with a film thickness equivalent to that when the thickness of the mainspring portion is 100 to 200 μm, as in the other embodiments already described. To do.

  Next, as shown in FIG. 15B, a photoresist is applied to the surface of the amorphous silicon layer 220, and a mask 23 based on the shape of the hairspring is formed by photolithography.

Next, as shown in FIG. 15C, the amorphous silicon layer 220 is dry-etched using an etching gas (for example, CF ₄ , SF ₆ , HBr, etc.) (arrow F). As a result, the outer shape of the hairspring 100 is formed on the silicon wafer 20.

Next, as shown in FIG. 15D, the mask 23 is removed, and further, as shown in FIG. 15E, wet etching is performed using a predetermined etching solution (not shown) (for example, hydrofluoric acid), so that SiO 2 By removing the _two layers 210, the amorphous silicon layer 220 is cut off, and the amorphous mainspring 110 (that is, the hairspring 100) is formed.

  The method for manufacturing the hairspring when the crystal material is amorphous silicon has been described above. Amorphous generally means a state where there is no long-range order but short-range order. The amorphous silicon layer 220 does not have to be a structure composed of only silicon atoms, and may have a tetrahedral structure having, for example, oxygen atoms at the apexes centered on the silicon atoms as short-range order. Of course, if the structure of the amorphous silicon layer 220 is changed, the Young's modulus of the hairspring 100 also changes. Therefore, the structure may be selected in view of the desired Young's modulus.

Further, the amorphous material may be polysilicon. In that case, polysilicon is formed on the SiO ₂ layer 210 in the step shown in FIG. Since a known film forming technique can be used for the method, description thereof is omitted.

[Description of Crystallization by Laser Irradiation of Hairspring of Fifth Embodiment: FIG. 16]
Next, how the mainspring portion 110 is crystallized by irradiating the mainspring portion 110 of the hairspring 100 in the laser irradiation step will be described with reference to FIG. As described above, this laser irradiation step corresponds to the laser irradiation step (ST6) of the first embodiment. The laser will be described as a femtosecond laser 51.

  Here, FIG. 16 is an enlarged cross-sectional view of a part of the mainspring portion, which is equivalent to the portion shown in FIG. 7, and is an irradiation region E that is effective for rate adjustment shown in FIG. 6 (a). It is a part of the mainspring portion in the region corresponding to.

FIG. 16A illustrates a case where the irradiation of the femtosecond laser 51 is weak, and the crystalline region 110b of the mainspring portion 110 to be irradiated is partially formed inside the mainspring portion 110 as illustrated. Is done. Note that the periphery other than the crystalline region 110b is an amorphous region 110a.

  Further, FIG. 16B illustrates a case where the intensity of the femtosecond laser 51 is medium, and the crystalline region 110c of the mainspring portion 110 to be irradiated is the interior of the mainspring portion 110 as illustrated. Formed in the majority of

  Further, FIG. 16C illustrates a case where the irradiation of the femtosecond laser 51 is strong, and the crystalline region 110d of the mainspring portion 110 to be irradiated is formed in the entire interior of the mainspring portion 110 as illustrated. Is done.

  The strength of the femtosecond laser 51 is calculated by controlling the irradiation condition based on the measurement result of the rate of at least one of the laser output, the irradiation frequency, and the irradiation angle, as in the first embodiment described above. Will be implemented. That is, by changing at least one condition of the laser output, the irradiation frequency, and the irradiation angle, the amount of energy per unit time irradiated to the mainspring portion 110 can be changed, and the range of the crystalline region can be changed to The Young's modulus of the mainspring can be adjusted.

  That is, as shown in FIG. 16A, if the crystalline region 110b is formed in a small region inside the mainspring portion 110, the Young's modulus increases little, so the rate change (improvement) is small. . In addition, as shown in FIG. 16C, if the crystalline region 110d is formed in the whole mainspring portion 110, the Young's modulus increases and the rate change (improvement) increases accordingly. The rate adjustment range can be expanded.

  Further, similarly to the first embodiment already described, by changing the irradiation range of the femtosecond laser 51, it is possible to adjust the rate by changing the range and position of the irradiation region. That is, the angle θ of the irradiation region E, which is effective for adjusting the rate, is changed.

  Of course, the rate can be adjusted by changing the depth of focus of the femtosecond laser 51. That is, by adjusting the focal depth of the femtosecond laser 51 and focusing the femtosecond laser 51 near the center D of the cross section of the mainspring portion 110 as shown in FIG. The amount of energy per hit can be increased, and the mainspring 110 can be crystallized reliably. In this way, the femtosecond laser 51 can be crystallized by focusing, even if silicon dioxide is a transparent material.

  The hairspring 100 according to the fifth embodiment can adjust the rate finely and with high accuracy by laser irradiation after the hairspring 100 is incorporated into a drive mechanism (for example, a watch), as in the embodiment described above.

  In addition, since the Young's modulus is changed and the rate is adjusted by crystallizing the inside of the hairspring 100, there is no scattering of the hairspring residue around the surface, which is generated by adjusting the surface of the hairspring 100.

  Of course, since the balance of expansion and contraction of the hairspring 100 can be improved by irradiation with the femtosecond laser, a hairspring having excellent isochronism can be manufactured.

  The fifth embodiment described above is an example in which the crystal structure of the hairspring is amorphous, and as described above, adjusting the rate by performing laser irradiation is similar to the embodiment described above. It is the same. Therefore, it goes without saying that the manufacturing method of the second to fourth embodiments may be applied to the hairspring 100 described in the fifth embodiment.

  Note that the flowcharts, cross-sectional views, and the like shown in the embodiments of the present invention are not limited thereto, and may be arbitrarily changed as long as they satisfy the gist of the present invention.

For example, in the fifth embodiment, amorphous silicon and polysilicon have been described as materials whose crystal material is amorphous, but it goes without saying that these may be stacked. That is, after the SiO ₂ layer 210 is formed on the silicon wafer 20 shown in FIG. 15, amorphous silicon and polysilicon are laminated. Since both materials have different hardnesses, the Young's modulus when a hairspring is constructed is also different. By laminating both materials, the desired balance of the Young's modulus can be configured.

  Then, as shown in FIG. 16, the main body 110 is crystallized by laser irradiation in accordance with the performance of the desired balance spring, such as by performing either or both of laminated amorphous silicon and polysilicon. be able to.

  The method of manufacturing the hairspring of the present invention can be used widely as a method of manufacturing a hairspring, particularly as a speed adjusting mechanism incorporated in a mechanical timepiece, because the rate of the hairspring can be easily adjusted with high accuracy. it can.

DESCRIPTION OF SYMBOLS 1 Quartz wafer 10 Hairspring 11 Spring part 11a Crystal area | region 11b, 11c, 11d Amorphous area | region 12 Beard ball 12a Through-hole 12b Connection part 13 Beard 15 Metal film 16 Trimming area | region 30 Temp 40 Drive mechanism 50 Laser irradiator 51 Femto Second laser 60 Step measurement system 64 Laser Doppler vibration measuring instrument 70 Laser irradiation system 110b, 110c, 110d Crystalline region

Claims (9)

A whisker having a through-hole for fitting with a rotating shaft body, a coil-shaped mainspring part that is connected to the whistle by a connecting part and is wound around the whisker around the through-hole. A method for manufacturing a hairspring, which is obtained by processing a material having a predetermined crystal structure,
A rate measuring process for measuring the rate;
A laser irradiation step of irradiating a predetermined region of the mainspring part with a laser;
A method of manufacturing a hairspring. 2. The method of manufacturing a hairspring according to claim 1, wherein the predetermined region is a region facing the connection portion with the through-hole of the hair ball interposed therebetween. 3. The hairspring of claim 1, wherein the laser irradiation step changes the crystal structure of the predetermined region to amorphous or crystalline based on a measurement result of the rate measurement step. Production method. The whisker according to any one of claims 1 to 3, wherein the laser irradiation step controls at least one of the output, focal depth, irradiation range, irradiation frequency, and irradiation angle of the laser. A method for manufacturing the mainspring. The method of manufacturing a hairspring according to any one of claims 1 to 4, wherein the laser irradiation step irradiates a femtosecond laser. The method of manufacturing a hairspring according to any one of claims 1 to 5, wherein in the rate measurement step, the hairspring is vibrated and the rate is measured from the vibration state. The method of manufacturing a hairspring according to any one of claims 1 to 5, wherein, in the rate measurement step, the hairspring is incorporated in a drive mechanism, and the hairspring is expanded and contracted to measure the rate. . The whiskers according to any one of claims 1 to 7, further comprising a wet etching step of immersing the hairspring in a predetermined etching solution after the laser irradiation in the laser irradiation step. A method for manufacturing the mainspring. A protective film forming step of forming a protective film having a crystal structure different from that of the hairspring in the mainspring portion;
A trimming step of partially removing the protective film;
The method for manufacturing a hairspring according to any one of claims 1 to 8, further comprising:

Images