Vibration test device for a timepiece

Abstract

Testing device for testing a timepiece (20), comprising: - a source of vibration excitation (30), - a measuring device (40) for measuring a vibration response, - a positioning device (50), with main guide means (55), arranged to place the timepiece (20) in a first position, - a holding device with clamping means (200) for clamping the timepiece (20) in the first position, characterized in that the clamping means (200) are floating, the holding device comprising secondary guide means (100), arranged to provide at least one degree of freedom to the clamping means (200), to allow movement to place the timepiece (20) in at least a second position.

Description

Technical field of the invention

[0001] The present invention relates generally to a vibration testing device for a timepiece, and in particular, the invention relates to a vibration testing device for a timepiece made of silicon or comprising silicon and still attached to a silicon wafer. State of the art

[0002] In the prior art of silicon watch parts, document WO2022152857A1 is known, which discloses a device for vibration testing of silicon balance springs still attached to a silicon wafer. On the other hand, this document does not propose a solution for quickly and / or reliably testing all the balance springs on the same wafer. Statement of the invention

[0003] An aim of the present invention is to address the drawbacks of the prior art mentioned above and in particular, first of all, to propose a vibration testing device for quickly and / or reliably testing all the silicon parts of the same wafer.

[0004] For this, a first aspect of the invention relates to a vibration testing device for testing a timepiece comprising silicon and attached to a silicon wafer, the testing device comprising: a source of vibrational excitation, arranged to excite the timepiece, a measuring device arranged to measure a vibrational response of the timepiece, a device for positioning the silicon wafer, with main guide means, arranged to guide and move the silicon wafer in at least one direction of movement at least to put the timepiece in a first position, a holding device with clamping means arranged to clamp the silicon wafer with the timepiece in the first position, characterized in that the clamping means are floating, the holding device comprising secondary guide means, arranged to provide at least one degree of freedom to the clamping means and to the silicon wafer clamped by the clamping means, to allow a movement imposed by the positioning device to put the timepiece in at least a second position.According to the above implementation, the clamping means are floating, that is to say they have at least one degree of freedom of movement (typically a translation) to follow the wafer moved by the positioning device, without unclamping it. For this purpose, the holding device comprises secondary guide means provided to allow the assembly (comprising the clamping means and the clamped silicon wafer) to follow the movement imposed by the positioning device to place the timepiece in at least a second position. In other words, once clamped by the clamping means, the wafer can still be moved to bring the timepiece into a second position from the first position. Typically, a vibration measurement can be carried out in the first position and in the second position.Thus, for the same watch part, once the plate is clamped (to eliminate the risk of parasitic vibrations), several measurements can be taken at different locations on the watch part.

[0005] The test device may further have the following characteristics, taken individually or in combination.

[0006] According to one embodiment: the positioning device is arranged to guide and move the silicon wafer in at least two mutually orthogonal directions of movement and preferably each transverse to the direction of measurement of the vibration response, and / or the secondary guide means are arranged to guide the clamping means in at least two mutually orthogonal directions of movement and preferably each transverse to the direction of measurement of the vibration response, and / or the direction of measurement of the vibration response is normal to a plane of the silicon wafer. In other words, the positioning device can impose movements in an X direction and a Y direction contained in the plane of the wafer, and the clamping means are floating in X and Y.

[0007] According to one embodiment, the first position is a measuring position, and / or the second position is a measuring position. In particular, the first position is a measuring position on the timepiece, and the second position is a measuring position on the same timepiece. In particular, between the first position and the second position, the plate remains clamped.

[0008] According to one embodiment, the test device comprises a frame and: the main guide means are arranged between the frame and the silicon wafer, and / or the secondary guide means are arranged between the frame and the clamping means. According to this implementation, the clamping means are floating relative to the frame.

[0009] According to one embodiment, the holding device comprises return means, arranged to return the clamping means to a neutral position. According to this implementation, the return means can return the clamping means to the neutral position as soon as the clamping means release the silicon wafer.

[0010] According to one embodiment, before clamping, the neutral position is aligned with the first position.

[0011] According to one embodiment, the recall means comprise: a male shape such as an index, a female shape with a bottom and at least one slope leading to the bottom, such as a conical cup, an elastic return member or a pneumatic or hydraulic actuator exerting a return force to push the male shape towards the bottom. According to one embodiment, the female shape has a dimension at least equal to a predetermined measurement zone on the timepiece. In particular, the female shape has a dimension (preferably transverse to the measurement direction or parallel to a plane of the plate) at least equal to the distance between the first position and the second position.

[0012] According to one embodiment, the clamping means comprise a lower jaw and an upper jaw, arranged to grip the silicon wafer in a vice. Typically, the lower jaw and the upper jaw form a clamping clamp.

[0013] According to one embodiment, the clamping means comprise: at least one access opening, provided to allow free access between the timepiece to be tested, and the vibration source and / or the measuring device, and / or at least one recess between a support surface provided to contact the silicon wafer and a surface opposite the timepiece, or opposite a timepiece of the silicon wafer and adjacent to the timepiece to be tested.

[0014] According to one embodiment, the holding device comprises a clamping force limiter, such as a spring system. Thus, the clamping means cannot exert a clamping force greater than a threshold force, to avoid any harmful stress on the plate.

[0015] According to one embodiment, the holding device comprises a clamping actuator, and the clamping force limiter is arranged between the clamping actuator and the silicon wafer.

[0016] According to one embodiment: the positioning device comprises at least one displacement actuator, arranged to cause the silicon wafer to move from the first position to said at least one second position, and / or the portion of the holding device arranged between the silicon wafer and the secondary guide means (i.e. at least the clamping means) is driven in movement with or by the silicon wafer clamped by the clamping means and / or the holding device is free of a displacement actuator arranged to cause the silicon wafer to move from the first position to said at least one second position. In other words, the holding device is passive, i.e. its floating part is driven with or by the silicon wafer.

[0017] According to one embodiment, the positioning device comprises a positioning imprint, arranged to receive the silicon wafer, and to block at least one degree of freedom between the positioning imprint and the silicon wafer according to said at least one direction of movement between the first position and said at least one second position. Preferably, the positioning imprint is provided to block at least two degrees of freedom in translation. In particular, the positioning imprint can match a periphery of the silicon wafer. The imprint can comprise an index cooperating with a housing of corresponding shape provided on the periphery of the wafer, to block the wafer in rotation.

[0018] According to one embodiment: the main guide means are arranged to guide and move the silicon wafer over a main stroke of between 0.5 times and 3 times an overall dimension of the silicon wafer, preferably between 0.8 times and 2 times an overall dimension of the silicon wafer, and very preferably between 1 time and 1.3 times an overall dimension of the silicon wafer, and / or the secondary guide means are arranged to guide the clamping means and the silicon wafer clamped by the clamping means over a secondary stroke of between 0.5 times and 3 times an overall dimension of the timepiece, preferably between 0.8 times and 2 times an overall dimension of the timepiece, and very preferably between 1 time and 1.3 times an overall dimension of the timepiece.According to this implementation, the main guide means have a total stroke similar to a size of the silicon wafer, while the secondary guide means have a total stroke similar to a size of the timepiece, i.e. much less than the stroke of the main guide means.

[0019] According to one embodiment, the secondary guide means comprise at least one ball guide system, such as a ball rail / slide assembly. A YY table may be provided. Description of the figures

[0020] Other characteristics and advantages of the present invention will appear more clearly on reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the appended drawings, in which: [ fig. 1 ] represents a simplified diagram of a side view of a test device according to the invention, comprising a holding device with clamping means clamping a silicon wafer placed in position by a positioning device to apply a vibration test to a silicon timepiece still attached to the silicon wafer; [ fig. 2 ] represents a simplified diagram of a rear view and in section along the II-II axis of the figure 1 of the test device of the figure 1 ; [ fig. 3 ] represents a perspective view of the test device of the figures 1 And 2 . Detailed description of embodiment(s)

[0021] There figure 1 represents a simplified diagram of a side view of a test device according to the invention, comprising in particular a holding device with clamping means 200 clamping a silicon wafer 10 placed in position by a positioning device 50 to apply a vibration test to a timepiece 20 still attached to the silicon wafer 10. The figure 2 represents a simplified diagram of a rear view and section along the II-II axis of the figure 1 of the test device of the figure 1 . For clarity, some parts are shown in section, to fit other components that would otherwise be hidden.

[0022] The silicon wafer 10 of this example may be a wafer with a buried oxide layer (SOI type), but any other type of wafer may be provided. The timepiece 20 may be a silicon part obtained by etching silicon, for example using a deep ion reactive etching process. The timepiece 20 may be, for example, a watch balance spring, a watch balance, or any other type of silicon part still bridged or attached to the substrate of the silicon wafer 10. It may be noted that the silicon wafer 10 supports several timepieces 20, each still present in an etching well, which may be identical or different. The material of the silicon wafer 10 in which the timepieces 20 are etched is silicon. Monocrystalline or polycrystalline silicon may be provided. However, any other material and any other type of part may be provided.

[0023] The testing device of the figures 1 And 2 is intended to carry out a vibration test on a timepiece 20 of the silicon wafer 10, and preferably on all the timepieces 20 of the silicon wafer 10. It may be possible to choose not to test all the parts, but the test device advantageously allows them all to be tested if necessary.

[0024] For this purpose, the timepiece 20 is placed opposite a vibration excitation source 30, arranged to excite the timepiece 20, and a measuring device 40 arranged to measure a vibration response of the timepiece 20.

[0025] For example, the vibration excitation source 30 may be an acoustic source which may generate a sound wave to cause the timepiece 20 to vibrate, and the measuring device 40 may be a laser vibrometer which may measure a displacement, a speed or an acceleration of the vibrating timepiece 20.

[0026] The test device comprises a main frame 400 which supports the various components of the test device, in particular: the vibration excitation source 30, the measuring device 40, a positioning device 50, for guiding and moving the silicon wafer 10 and its still attached timepieces 20, a holding device, provided in particular for clamping the silicon wafer 10 when a timepiece 20 is tested.

[0027] To position a timepiece 20 to be tested opposite the vibration excitation source 30 and the measuring device 40, the test device comprises a positioning device 50 secured to the frame 400 and comprising in particular: a positioning 51 with an imprint receiving the silicon wafer 10, main guide means 55, with at least one first main slide connection 56 (in a direction X) and at least one second main slide connection 57 (in a direction Y), at least one movement actuator, shown diagrammatically in the form of a motor M (in this example, it can be considered that two motors M are provided).

[0028] Thus, the positioning device 50 provides a mobile table XY supporting and locating the silicon wafer 10, and a control of the motors M makes it possible to move the silicon wafer 10 and therefore the timepieces 20 in the X or Y directions to place them opposite the source of vibration excitation 30 and the measuring device 40.

[0029] During a vibration test, parasitic vibrations may occur (the silicon wafer itself or even part of the tooling may start to vibrate) and alter the quality of the measurement of the vibration response. To eliminate these parasitic vibrations, it is proposed to clamp the silicon wafer 10 by holding it in a vice as close as possible to the watch part 20 to be tested.

[0030] For this purpose, the holding device generally comprises clamping jaws forming part of a clamping structure with: a lower clamping structure located generally under the silicon wafer 10 figure 1 Or 2 , and an upper clamping structure located generally above the silicon wafer 10 figure 1 Or 2 .

[0031] The lower clamping structure and the upper clamping structure have the same simplified symmetrical architecture on the figure 1 Or 2 , also for readability reasons, the components of the lower clamping structure and the upper clamping structure are only referenced once.

[0032] In detail, the holding device and in particular each of the lower clamping structure and the upper clamping structure comprises: a vertical guide device 300, with a vertical pad 302 which can slide on a vertical rail 301, a mobile chassis 210, comprising a support base 211 and a clamping arm 212, clamping jaws, carried by the clamping arms 212, and contacting or pinching the silicon wafer 10 on the figure 1 , thus forming clamping means 200, the clamping means 200 being provided to allow free access to the timepiece 20 to be tested (the clamping jaws are drilled and generally tubular in shape), clamping means 220, interposed between the lower clamping structure and the upper clamping structure, and comprising a clamping cylinder 221 and a force limiter 222, secondary guide means 100, interposed between the support base 211 and the clamping arm 212, and comprising a first secondary slide connection 110 (along the X direction), with first secondary rails 111 and first secondary pads 112, and a second secondary slide connection 120 (along the Y direction), with second secondary rails 121 and second secondary pads 122, return means 500, interposed between the base support 211 and the clamping arm 212,and comprising in particular a base 501 housing a spring pusher 502 and a cup 503 receiving the free end of the spring pusher 502 (a pneumatic or hydraulic actuator can be provided instead of the spring pusher).

[0033] There figure 3 represents a perspective view of the test device of the figures 1 And 2 The silicon wafer is not visible on the figure 3 , to clearly show: the installation 51 which comprises a circular imprint capable of receiving the silicon wafer, the lower clamping structure and the upper clamping structure each capable of sliding in the Z direction via the support bases 211 of the mobile chassis 210 secured to the vertical guide devices 300, the clamping means 200 carried by the clamping arm 212 of the mobile chassis 210, the positioning device 50 fixed to the chassis 400 to move and guide the installation 51 in the X and Y directions, the secondary guide means 100 interposed between the clamping means 200 and the chassis 400.

[0034] It can be noted that each of the lower clamping structure and the upper clamping structure is movable in the Z direction thanks to the vertical guide devices 300, and the actuation of the clamping cylinder 221 allows: to move the clamping means 200 away from the silicon wafer 10 to release or unclamp it, or to bring the clamping means 200 closer to the silicon wafer 10 to pinch or clamp it as in the figure 1 Or 2 .

[0035] It may be noted that the force limiter 222 (for example a spring or a calibrated gas cylinder) makes it possible to limit the maximum force applied by the clamping means to the silicon wafer, which cannot exceed a threshold force (that of the spring or the calibrated gas cylinder). Thus, the silicon wafer 10 and / or the timepiece 20 is protected from excessive forces and / or deformations which could occur during clamping.

[0036] Moreover, as we can see, figure 1 , the silicon wafer 10 is clamped by the clamping means 200 and the timepiece 20 to be tested is in a first position (or initial or reference position), in which it is possible to make a first vibration measurement. It may be interesting to make other measurements on the same timepiece 20, and the test device makes it possible to do this without unclamping the silicon wafer 10.

[0037] Indeed, the secondary guide means 100 are interposed between the support base 211 and the clamping arm 212 and are therefore arranged between the clamping means 200 and the frame 400. The secondary guide means 100 comprise two secondary sliding connections, so that the clamping means 200 have two degrees of freedom in translation relative to the frame 400, and therefore the clamped silicon wafer 10 also has these two degrees of freedom in translation.

[0038] It is therefore possible to move the clamped silicon wafer 10, by actuating the motors M of the positioning device 50 to move it from the first position of the figure 1 to a second position in which a second vibration measurement can be carried out on the timepiece opposite the vibration excitation source 30. It is therefore possible to carry out several sequential measurements on the same timepiece 20 without having to unclamp the silicon wafer 10. During these movements from the first position to the second position, it is therefore the internal members of the secondary guide means 100 which will slide between them, to “follow” the silicon wafer 10 and its positioning 51, so that the clamping means 200 are floating in the X and / or Y direction.

[0039] It may be noted that the clamping means 200 are also floating in the Z direction. Indeed, if the main guide means 55 define directions of movement that are slightly different or slightly non-parallel with the directions of movement defined by the secondary guide means 100, then the vertical guide devices 300 will slide to follow or compensate for these differences.

[0040] Once a timepiece 20 has been tested, it is possible to control the clamping cylinder 221 to move the clamping means 200 away from the silicon wafer 10 and place another timepiece 20 of the silicon wafer 10 opposite the vibration excitation source 30 and the measuring device 40.

[0041] It may be noted that when the clamping means 200 release the silicon wafer 10, then the return means 500 can return the clamping means to a neutral position. Indeed, it may be noted that on the figure 1 , the clamping jaws are coaxial with the source of vibration excitation 30 and the measuring device 40, since the timepiece 20 of the figure 1 is in the first position. We can notice on the figure 1 that the spring index 502 is also coaxial with the bowl 503 and is aligned with the top or bottom of the bowl 503.

[0042] Any movement of the clamped silicon wafer 10 will have the effect of shifting the spring index 502 from the top or bottom of the bowl 503 and compressing the spring. This relative movement occurs when the positioning device 50 moves the timepiece 20 from the first position to the second position: the spring of the spring pusher 502 is stretched, and if the clamping means 200 release the silicon wafer 10, then the spring pusher 502 relaxes to return to align with the bottom or top of the bowl 503, simultaneously returning the clamping means to the neutral position of the figure 1 .

[0043] In the exemplary embodiment, a silicon wafer with an overall diameter of 150 mm can be provided, and each of the timepieces 20 can have an overall diameter of between 3 and 5 mm. By way of example, it can be provided that: the main guide means 55 allow movement in the X direction and in the Y direction with a stroke of approximately 150 mm, and / or the secondary guide means 100 allow movement in the X direction and in the Y direction with a stroke of approximately 5 mm or 10 mm.

[0044] In other words, the secondary guide means 100 are only provided to allow movement of the clamping means 200 and of the clamped silicon wafer 10 over strokes allowing measurements on a single timepiece 20, while the main guide means 55 allow movement over the entire silicon wafer 10.

[0045] Thus, each watch part 20 can be tested individually, by making several vibration measurements for each part without unbridling the silicon wafer 10. This makes it possible in particular to: simplify the design of the clamping means 200, and / or limit the risks of damaging the silicon wafer 10 and / or the timepieces 20, keep the same clamping conditions and therefore have the same boundary conditions for the iterative tests of the same timepiece 20, be able to test all the parts of the same wafer if necessary, the clamping means being repositioned around each part to be tested.

[0046] Preferably, the clamping jaws are sized so as to surround a single timepiece 20, bearing on the non-engraved plate portions remaining between the engraved timepieces. Industrial application

[0047] A test device according to the present invention, and its manufacture, are capable of industrial application.

[0048] It will be understood that various modifications and / or improvements obvious to those skilled in the art may be made to the various embodiments of the invention described in the present description without departing from the scope of the invention.

[0049] In particular, the main guide means and the secondary guide means of the given example comprise rail and guide shoe guide systems (for example ball shoes), but column guides, guides with precision slides can be provided. A plane connection without imposed X or Y direction can also be provided.

[0050] The test device can be used to perform vibration tests, but it can be planned to use it for optical tests, such as metrological tests.

Claims

1. Vibration testing device for testing a timepiece (20) comprising silicon and attached to a silicon wafer (10), the testing device comprising: - a vibration excitation source (30), arranged to excite the timepiece (20), - a measuring device (40) arranged to measure a vibration response of the timepiece (20), - a device for positioning (50) the silicon wafer (10), with main guide means (55), arranged to guide and move the silicon wafer (10) in at least one direction of movement at least to put the timepiece (20) in a first position, - a holding device with clamping means (200) arranged to clamp the silicon wafer (10) with the timepiece (20) in the first position, characterized in thatthe clamping means (200) are floating, the holding device comprising secondary guide means (100), arranged to provide at least one degree of freedom to the clamping means (200) and to the silicon wafer (10) clamped by the clamping means (200), to allow a movement of the silicon wafer (10) imposed by the positioning device (50) to place the timepiece (20) in at least a second position.

2. Test device according to claim 1, wherein: - the positioning device (50) is arranged to guide and move the silicon wafer (10) in at least two directions of movement orthogonal to each other and preferably each transverse to the direction of measurement of the vibration response, and / or - the secondary guide means (100) are arranged to guide the clamping means (200) in at least two directions of movement orthogonal to each other and preferably each transverse to the direction of measurement of the vibration response, and / or - the direction of measurement of the vibration response is normal to a plane of the silicon wafer (10).

3. Test device according to one of claims 1 to 2, comprising a frame (400) and in which: - the main guide means (55) are arranged between the frame (400) and the silicon wafer (10), and / or - the secondary guide means (100) are arranged between the frame (400) and the clamping means (200).

4. Test device according to one of claims 1 to 3, in which the holding device comprises return means (500), arranged to return the clamping means (200) to a neutral position.

5. Test device according to claim 4, wherein before clamping, the neutral position is aligned with the first position.

6. Test device according to one of claims 4 or 5, in which the return means (500) comprise: - a male shape such as an index, - a female shape with a bottom and at least one slope leading to the bottom, such as a conical bowl, - an elastic return member or a pneumatic or hydraulic actuator exerting a return force to push the male shape towards the bottom.

7. Test device according to one of claims 1 to 6, in which the clamping means (200) comprise a lower jaw and an upper jaw, arranged to hold the silicon wafer (10) in a vice.

8. Test device according to one of claims 1 to 7, in which the clamping means (200) comprise: - at least one access opening, provided to allow free access between the timepiece (20) to be tested, and the vibration source and / or the measuring device (40), and / or - at least one recess between a support surface provided to contact the silicon wafer (10) and a surface facing the timepiece (20), or facing a timepiece (20) of the silicon wafer (10) and adjacent to the timepiece (20) to be tested.

9. Test device according to one of claims 1 to 8, in which the holding device comprises a clamping force limiter (222), such as a spring system.

10. Test device according to claim 9, wherein the holding device comprises a clamping actuator, and wherein the clamping force limiter (222) is arranged between the clamping actuator and the silicon wafer (10).

11. Test device according to one of claims 1 to 10, wherein: - the positioning device (50) comprises at least one displacement actuator, arranged to cause the displacement of the silicon wafer (10) from the first position to said at least one second position, and / or - the portion of the holding device arranged between the silicon wafer (10) and the secondary guide means (100) is driven in displacement with or by the silicon wafer (10) clamped by the clamping means (200) and / or - the holding device is free of a displacement actuator arranged to cause the displacement of the silicon wafer (10) from the first position to said at least one second position.

12. Test device according to one of claims 1 to 11, wherein the positioning device (50) comprises a positioning imprint, arranged to receive the silicon wafer (10), and to block at least one degree of freedom between the positioning imprint and the silicon wafer (10) according to said at least one direction of movement between the first position and said at least one second position.

13. Test device according to one of claims 1 to 12, wherein: - the main guide means (55) are arranged to guide and move the silicon wafer (10) on a main stroke of between 0.5 times and 3 times an overall dimension of the silicon wafer (10), preferably between 0.8 times and 2 times an overall dimension of the silicon wafer (10), and very preferably between 1 time and 1.3 times an overall dimension of the silicon wafer (10), and / or - the secondary guide means (100) are arranged to guide the clamping means (200) and the silicon wafer (10) clamped by the clamping means (200) on a secondary stroke of between 0.5 times and 3 times an overall dimension of the timepiece (20), preferably between 0.8 times and 2 times an overall dimension of the timepiece (20), and very preferably between 1 time and 1.3 times an overall dimension of the timepiece (20).

14. Test device according to one of claims 1 to 13, wherein the secondary guide means (100) comprise at least one ball guide system, such as a ball rail / slide assembly.

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