Method for manufacturing sapphire watch elements, and watch elements

Abstract

To provide sapphire watch components, particularly sapphire glass, that are resistant to external stress. [Solution] An element 100 of a glass type watch case 400, the element 100 includes an outer surface 100a intended to be in contact with the external environment, an inner surface 100b intended to be in contact with the internal volume of the watch case 400, and an outer edge 100d connecting the outer surface 100a and the inner surface 100b, wherein the outer edge 100d includes a slot 1c, and the inner surface 100b includes a recess 1d such that the outer edge 100d includes a skirt 1f.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a sapphire watch component. The present invention also relates to a watch component, in particular a watch component obtained by said method, in particular a watch case component. The present invention also relates to a watch movement comprising said component or a watch case comprising said watch component. Finally, the present invention relates to a timepiece comprising said component, said watch movement or said watch case.

Background Art

[0002] Although sapphire is extremely durable, unexpected impacts can cause breakage, so problems often arise regarding the impact resistance of sapphire watch glasses. In addition, chipping may occur around the edges thereof, particularly since these glasses are intended to cover the bezel of small watches, which are therefore prone to experiencing impacts during daily wear of the small watch. This risk is even more pronounced for concave glasses that have very small thickness and / or include areas of low mechanical strength in cross-section.

[0003] Conventionally, uncolored sapphire glass is - a first step of preparation P1, at the end of which a glass blank is obtained from a sapphire boule or slab, - a second step of machining P2, at the end of which an unfinished glass is obtained from the glass blank, - a third step of finishing P3, at the end of which a final glass is obtained, obtained by a method comprising three standard steps. More specifically regarding the glass of a small watch, its thickness is typically sized to withstand various external stresses such as pressure and impact. The dimensions of the case are therefore determined, in particular, by the dimensions of the glass. More specifically, the thicker the glass, the greater its resistance to various external stresses, which results in a particularly thick case. Thinning the glass, and thus the case, requires a redefinition of how the glass is assembled and a manufacturing method that allows for obtaining glass that is sufficiently resistant to various stresses.

[0004] Patent Document 1 discloses a miniature watch case that enables the assembly of thin, hard glass made of a rigid material. The miniature watch case includes a notch in the glass, which houses a seal intended to maintain and guarantee the water resistance of the case at the height of the glass. At the bottom, the notch in the glass includes a groove that allows for the insertion of a seal sized appropriately for inserting thin glass. The groove prevents the seal from curling during insertion and, for aesthetic reasons, from protruding above the glass after assembly. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Swiss Patent No. 718724 [Overview of the project] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a method for manufacturing sapphire watch components, particularly sapphire glass, that are resistant to external stress. In particular, the present invention proposes a method for manufacturing sapphire watch elements, especially glass, that improves reliability. The present invention also proposes an optimized assembly of glass, particularly in the view of thin, small watch cases. [Means for solving the problem]

[0007] According to a first aspect of the present invention, the subject matter is defined by the following proposals. 1. A method for manufacturing a sapphire watch element (100), the method comprising a machining step and a subsequent finishing step, The method further includes a first stress relief heat treatment step, which includes a first holding stage at a first temperature higher than 1100°C after the machining step. Manufacturing method.

[0008] 2. The first temperature is higher than 1600°C and / or The first temperature is lower than 2000°C, or lower than 1950°C, or lower than 1800°C, or lower than 1750°C. The manufacturing method described in Proposal 1.

[0009] 3. The first stress relief heat treatment step is performed between the machining and finishing stages. The manufacturing method described in Proposal 1 or 2.

[0010] 4. The first stress relief heat treatment step is performed between the two consecutive polishing steps of the finishing stage. The manufacturing method described in Proposal 1 or 2.

[0011] 5. The manufacturing method includes a second stress relief heat treatment step, which includes a maintenance stage at a temperature between 1000°C and 1200°C, particularly at a temperature of about 1050°C. A manufacturing method described in any one of Proposals 1 to 4.

[0012] 6. The second stress relief heat treatment step is performed between the machining and finishing stages. The manufacturing method described in Proposal 5.

[0013] 7. The manufacturing method includes a third stress relief heat treatment step, which is performed between two consecutive machining steps of the machining stage, and includes a holding stage at a temperature between 1000°C and 1200°C, particularly at a temperature of about 1050°C. The manufacturing method according to any one of aspects 1 to 6.

[0014] 8. The manufacturing method comprises: a preparation step preceding said machining step, and a fourth stress relief heat treatment step comprising a holding stage at a temperature between 1000°C and 1200°C, particularly at about 1050°C, carried out between said preparation step and said machining step, comprising The manufacturing method according to any one of aspects 1 to 7.

[0015] 9. Said first holding stage at said first temperature has a duration of between 2 hours and 15 hours, typically 5 hours, The manufacturing method according to any one of aspects 1 to 8.

[0016] 10. One, some or all of said second, third and fourth steps comprise a holding stage at a temperature of about 1050°C, said holding stage having a duration of between 2 hours and 15 hours, typically 5 hours, The manufacturing method according to any one of aspects 1 to 9.

[0017] 11. One, some or all of said first, second, third and fourth steps are carried out under a controlled atmosphere, particularly, under vacuum, or under a neutral or inert gas, or under a reducing or deoxidizing atmosphere using a reducing gas such as an H2-N2 mixture, or using a neutral or inert gas combined with a graphite heating element that generates carbon monoxide for example, or under an oxidizing atmosphere, for example under air, carried out, The manufacturing method according to any one of aspects 1 to 10.

[0018] 12. The timepiece element (100) is glass, and the machining step comprises producing a recess in the glass, and / or the timepiece element (100) is made of colorless sapphire or uncolored sapphire, The production method according to any one of aspects 1 to 11.

[0019] 13. The timepiece element is an external component element or a timepiece movement element, in particular, a glass intended in particular to be attached to a case body or a case back, or a case back, or a crown, or a bezel, or a bezel disk, or a case body, or a case body comprising glass, that is, the case body forms glass, or the case body is formed integrally with the glass, or an indicator disk, in particular a calendar disk, which is The production method according to any one of aspects 1 to 11.

[0020] 14. A sapphire timepiece element (100), in particular made of colorless sapphire or uncolored sapphire, obtained by carrying out the production method according to any one of aspects 1 to 13.

[0021] 15. A timepiece case (400) comprising the sapphire timepiece element (100) according to aspect 14.

[0022] 16. A timepiece movement (150) comprising the sapphire timepiece element (100) according to aspect 14.

[0023] 17. A timepiece (300), in particular a wristwatch, comprising the sapphire timepiece element (100) according to aspect 14, and / or the timepiece case (400) according to aspect 15, and / or the timepiece movement (150) according to aspect 16,

[0024] ​According to a second aspect of the present invention, the subject matter is defined by the following proposal. 18. An element (100) of the glass-type watch case (400) (300), wherein the element is The outer surface (100a) is intended to come into contact with the external environment, An inner surface (100b) intended to be in contact with the internal volume of the watch case, An outer edge (100d) connecting the outer surface and the inner surface, Includes, The outer edge (100d) includes a slot (1c), and the inner surface includes a recess (1d) such that the outer edge (100d) includes a skirt (1f). element.

[0025] 19. The aforementioned element (100) is Transparent ceramics, especially transparent polycrystalline ceramics or transparent monocrystalline ceramics, Glass, especially tempered glass, or sapphire, It is made by The elements described in Proposal 18.

[0026] 20. The outer edge (100d) is On the first side of the slot (1c) is a first portion (1b) intended to cooperate with the seal (2), On the second side of the slot (1c), there is a second portion (1a) which is larger in dimensions than the first portion (1b), and in particular has a larger diameter. including, Elements as described in Proposal 18 or 19.

[0027] 21. The element is sized to withstand a pressure of at least 10 bar applied to the outer surface (100a). An element described in any one of proposals 18 to 20.

[0028] 22. The first thickness (e1) measured between the outer surface and the bottom of the recess is 1 mm or more and 1.5 mm or less, typically about 1.3 mm. An element described in any one of proposals 18 to 21.

[0029] 23. The second thickness (e2) measured between the bottom of the slot and the side wall of the recess is 0.35 mm or more and 0.5 mm or less. An element described in any one of proposals 18 through 22.

[0030] 24. The third thickness (e3) of the skirt is 0.4 mm or more and 0.6 mm or less. The elements described in any one of proposals 18 to 23.

[0031] 25. The ratio of the third thickness (e3) to the first thickness (e1) is less than 1, or 0.3 or more and 0.5 or less, typically 0.35 or 0.42. Elements described in Proposal 24 that reference Proposal 22.

[0032] 26. The depth (e4) of the recess (1d) is 0.2 mm or more and 0.6 mm or less. The elements described in any one of proposals 18 to 25.

[0033] 27. The thickness (e5) of the first portion (1b) is 0.3 mm or more and 0.4 mm or less, typically 0.38 mm. An element described in any one of proposals 18 through 26 that cites proposal 20.

[0034] 28. The ratio of the thickness (e5) of the recess (1d) to the depth (e4) is less than 1, or 0.7 or more and 0.8 or less, typically 0.76. The elements described in Proposal 26 or Proposal 27.

[0035] 29. The recess includes a flat edge (1g) between the bottom and the skirt, the flat edge (1g) having a radius between 0.1 mm and 0.7 mm, typically 0.3 mm or 0.6 mm. An element described in any one of proposals 18 through 28.

[0036] 30. The element is obtained by the method of any one of Proposals 1 to 13. An element described in any one of proposals 18 through 29.

[0037] 31. A watch case (400) including a watch element (100) as described in any one of proposals 18 to 30.

[0038] 32. Including a bezel (4) and a seal (2) disposed between the bezel and the watch element (100), The watch case (400) described in Proposal 31.

[0039] 33. Including a case back and a seal (2) disposed between the case back and the element (100), The watch case (400) described in Proposal 31.

[0040] 34. The seal (2) is Nylon or polyamide such as polyamide 6 or 6.6, or Zytel® or Grilamid®, or Thermoplastic elastomers or thermoplastic elastomer copolyesters such as Hytrel (registered trademark), It is made by A watch case (400) as described in any one of proposals 31 to 33.

[0041] 35. Including the case (3), the slot (1c) cooperates with the projection (2a) of the seal (2) to secure the watch element (100) in particular to the bezel (4) and / or the case (3) and / or the case back. A watch case (400) as described in any one of proposals 31 to 34.

[0042] 36. Including a body portion (3) having an opening dimension (d2), particularly an opening diameter (d2), wherein the dimensions of the bottom of the recess, particularly the diameter (d1) of the bottom of the recess, are greater than or equal to the opening dimension (d2), particularly the opening diameter (d2). A watch case (400) as described in any one of proposals 31 to 35.

[0043] 37. A clock element (100) as described in any one of proposals 18 to 30, and / or A watch case (400) as described in any one of proposals 31 to 36, Including watches (300), especially wristwatches.

[0044] The drawings show, as an example, three embodiments of the clock according to the present invention. [Brief explanation of the drawing]

[0045] [Figure 1] Figure 1 illustrates a first embodiment of the clock according to the present invention. [Figure 2] Figure 2 is a graph showing the effect of the manufacturing method according to the present invention on the characteristics of sapphire glass according to the first embodiment. [Figure 3] Figure 3 illustrates a second embodiment of the clock according to the present invention. [Figure 4] Figure 4 is a graph showing the effect of the manufacturing method according to the present invention on the characteristics of sapphire glass according to the second embodiment. [Figure 5] Figure 5 is a flowchart of the first embodiment of the manufacturing method according to the present invention. [Figure 6] Figure 6 is a flowchart of a second embodiment of the manufacturing method according to the present invention. [Figure 7] Figure 7 is a flowchart of a third embodiment of the manufacturing method according to the present invention. [Figure 8] Figure 8 is a flowchart of the fourth embodiment of the manufacturing method according to the present invention. [Figure 9] Figure 9 is a flowchart of the fifth embodiment of the manufacturing method according to the present invention. [Figure 10] Figure 10 is a detailed view of a second embodiment of the clock according to the present invention. [Figure 11] Figure 11 is a detailed view of a third embodiment of the clock according to the present invention. [Modes for carrying out the invention]

[0046] Three embodiments of the clock 300 according to the present invention will be described below with reference to Figures 1, 3, 10, and 11. The clock is, for example, a small clock, in particular a wristwatch. The clock includes a clock movement. The clock movement 200 is - Mechanical movements, especially automatic movements, or - Electronic movement, or - Hybrid movement That's fine.

[0047] The watch 300 also includes a case 400 which houses the watch movement 200 and is intended to protect the watch movement from the external environment.

[0048] Case 400 is, - Torso 3, - Glass 100, - Seal 2, and - Depending on the case, the bezel 4, for example, the bezel or bezel portion fixed in place to the case 3, - Depending on the case, the case back, which may be attached to or manufactured integrally with the case. Includes.

[0049] Watch 300, especially case 400 or watch movement 200, transparent watch element 100, especially, - In particular, glass, or intended to adhere to the barrel or case back. - The back cover, or - Crown, or - Bezel, or - Bezel disc, or - Torso, or - A body containing glass, i.e., the body forms glass, or the body is formed integrally with glass, - Indicator discs, especially calendar discs, Includes.

[0050] For this reason, the clock element 100 may be an external part element or a clock movement element.

[0051] Clock element 100 is, - Transparent ceramics, especially transparent polycrystalline ceramics or transparent single-crystal ceramics such as YAG, or - Glass, especially tempered glass, or -sapphire It can be made by hand.

[0052] The clock element 100 includes an axis A1 that extends parallel to the thickness (i.e., minimum dimension) of the clock element. Preferably, axis A1 is centered on the clock element 100.

[0053] According to various embodiments, the watch element 100 is preferably made of sapphire, preferably, - Machining stage, and then - Finishing stage, A method for manufacturing a clock element 100, obtained by carrying out one embodiment of the manufacturing method, further includes a first stress relief heat treatment step at a first temperature higher than 1100°C after the mechanical step.

[0054] The first temperature is preferably, - Higher than 1600℃, and / or - Below 2000°C, or below 1950°C, or below 1800°C, or below 1750°C.

[0055] The first stress relief heat treatment step is: - Between machining and finishing stages, or - Between the two consecutive polishing steps in the finishing stage, It may be done.

[0056] Experimental studies conducted by the applicant have shown that, in particular, the stress relief heat treatment step makes it possible to obtain elements, especially glass, that can better withstand unexpected impacts, especially drops from heights of 1 meter or more, which may occur accidentally when a wearer removes a miniature watch from their wrist. In particular, studies conducted by the applicant have shown that the stress relief heat treatment step can increase the height to which a miniature watch can be dropped before breakage occurs. The equipment used in these studies is a Bélier striker, as described in NIHS91-10 or ISO standard 1413. A series of two different tests were performed on miniature watch cases fitted with sapphire glass of different shapes. In particular, the equipment used is characterized by the provision of an aluminum shoe (rather than a hard material) so that the glass is breakable but the shoe is not. All cases were oriented in the same way so that the shoe first struck the edge or outer circumference of the glass.

[0057] The first series of tests relates to various configurations of flat circular glass having a thickness of 1.8 mm and a diameter of 30.38 mm (as shown in Figure 1), and having a type A crystal orientation obtained by the Bernoulli growth method. The glass further includes an annular groove or slot 1c, which allows the glass to be assembled onto the body via a seal intended to be housed within the groove.

[0058] Various configurations, - A standard first batch A of 100 pieces of glass obtained by the manufacturing method, which includes stress relief heat treatment TT1 at a temperature of 1100°C, performed between the second stage of machining P2 and the third stage of finishing P3. - (In addition to the stress relief heat treatment TT1 at a temperature of 1100°C performed between the second stage of machining P2 and the third stage of finishing P3) an additional stress relief heat treatment at 1650°C was performed during the third stage of finishing, for the second batch B of 100 pieces of glass. - (Instead of the stress relief heat treatment at a temperature of 1100°C performed between the second stage of machining P2 and the third stage of finishing P3) A single stress relief heat treatment at 1920°C was performed between the second stage of machining P2 and the third stage of finishing P3, for the third batch C of 100 pieces of glass. Includes.

[0059] In practice, - For the second batch B, the stress relief heat treatment is carried out in air, and the holding stage at 1650°C lasts for 5 hours. - For the third batch C, the stress relief heat treatment is carried out under neutral or inert gas conditions, particularly in an argon environment, and the holding stage at 1920°C is also sustained for 5 hours.

[0060] Figure 2 shows the gains resulting from heat treatments performed on batches B and C, which were carried out at higher temperatures (instead of the pre-stress relief heat treatment TT1 at 1100°C). The heat treatment of the third batch C is the most preferable, as it results in an average fracture height approximately 3.5 times higher than the average reference height Href measured in batch A. The second batch B also yields good results, with an average fracture height approximately twice that of the average reference height Href. In the graph, the ends of the vertical segments represent the obtained extreme values. Therefore, the box plot (or Tukey box plot) is used to represent the values ​​of the inspected glass. - Extreme values ​​(ends of vertical segments), - Median (horizontal segment within the rectangle), - The first quartile (the bottom of the rectangle), and - Third quartile (upper part of the rectangle), It represents.

[0061] Each rectangular dot represents the average value.

[0062] The second series of tests relates to various configurations of concave glass, i.e., glass having a recess 1d in the center, given a thickness of 1.3 mm and a diameter of 33.3 mm (shown in Figure 3). The glass has a type A crystal orientation obtained by the Bernoulli growth method. The glass further includes an annular groove or slot 1c formed on its outer circumference 100d or outer edge 100d, which allows the glass to be assembled onto the body via a seal intended to be housed within the same groove or slot.

[0063] Various configurations, - A standard first batch A' of 20 glasses obtained by the manufacturing method, which includes stress relief heat treatment TT1 at a temperature of 1100°C, performed between the second stage of machining P2 and the third stage of finishing P3. - (In addition to the stress relief heat treatment TT1 at a temperature of 1100°C performed between the second stage of machining P2 and the third stage of finishing P3) an additional stress relief heat treatment at 1600°C was performed during the third stage of finishing, for the second batch of 20 pieces of glass B'. - (In addition to the stress relief heat treatment TT1 at a temperature of 1100°C performed between the second stage of machining P2 and the third stage of finishing P3) an additional stress relief heat treatment at 1750°C was performed during the third stage of finishing, for the third batch of 20 pieces of glass C'. Includes.

[0064] The second series of tests also shows that the heat treatment performed at a higher temperature, i.e., the heat treatment of the third batch C', which has an average failure height of approximately four times the average failure height Href' of the reference first batch A', is the most preferable, as shown in Figure 4. The second batch B' also yields good results, with an average failure height of approximately 2.4 times the average reference height Href'.

[0065] In this case as well, the two series of tests demonstrate the advantages of the stress relief heat treatment performed at a very high temperature at the end of the method, whether in addition to or in addition to the stress relief heat treatment performed at 1100°C or a lower temperature.

[0066] A method for manufacturing a glass-type clock element 100 is: - At the end of this process, a glass blank is obtained from the sapphire boule or slab, the first stage of preparation P1. - At the end of this process, the second stage of machining P2 yields unfinished glass from the glass blank. - At the end of this process, the final glass is obtained, the third stage of finishing P3. It includes three stages.

[0067] The machining stage P2 and the finishing stage P3 differ in that the machining stage is a material removal stage consisting of material removal steps that obtain at least partially the shape of the watch element 100, and the finishing stage is a finishing stage consisting of finishing steps that obtain at least partially the surface finish of the watch element 100.

[0068] Preferably, the roughness Ra of the visible surface of the clock element 100 is such that the clock element 100, and in particular the other elements of the clock through which the glass 100 is provided, are visible. - Before the finishing stage (and therefore before the glass is installed in the watch), particles larger than 0.2 μm, - After the finishing stage (and therefore measurable especially on a watch), it is smaller than 0.2 μm.

[0069] Alternatively or additionally, the light transmission of the watch element 100, particularly through the visible surface of the glass 100, before the finishing stage (i.e., before the glass is mounted on the watch) is between 40% and 50%, while after the finishing stage it is greater than 80%.

[0070] Regardless of the embodiment or modification, the method includes a first stress relief heat treatment step TT1'. The first stress relief heat treatment step TT1' is - Performed after the second stage of machining P2, and - Includes a temperature maintenance stage where the temperature is constant, and is higher than 1100°C, or even higher than 1100°C, typically between 1600°C and 2000°C.

[0071] As shown in Figure 5, in the first embodiment of the method, this step may be performed between the second stage of machining P2 and the third stage of finishing P3.

[0072] As shown in Figure 6, in the second embodiment of the method, step TT1' may be performed during the third stage of finishing P3, that is, between the two steps relating to the third stage of finishing.

[0073] According to a particular modification of the second embodiment shown in Figure 7, step TT1' may be performed in addition to the second stress relief heat treatment step TT1, which may be performed at a temperature equal to about 1050°C, or at a temperature between 1000°C and 2000°C, and between the second stage of machining P2 and the third stage of finishing P3.

[0074] According to another specific modification of the second embodiment shown in Figure 8, the method includes two other stress relief heat treatment steps prior to the second embodiment, both of which include a temperature maintenance stage at approximately 1050°C, particularly between 1000°C and 1200°C. The method is - A heat treatment step TT3 is performed between the first stage of preparation P1 and the second stage of machining P2, - Heat treatment step TT2 is performed during the second stage of machining P2. It may include.

[0075] The first stress relief heat treatment step TT1' is, - At temperatures higher than 1100°C, even higher than 1100°C, especially above 1600°C, and or - At temperatures lower than 2000°C, or lower than 1950°C, or lower than 1800°C, or lower than 1750°C, It may be implemented.

[0076] As shown in Figure 9, regardless of the embodiment or modification, the first step of preparation P1 is particularly, - First step E11: Providing a sapphire blank, in particular a sapphire boule (obtained especially by the Bernoulli method) or a sapphire slab (obtained especially by the EFG method), - In order to obtain slices that preform the glass blank, the blank, especially the boule or slab, is cut in the second step E12. - Third and fourth steps E13 and E14, respectively, to obtain a glass blank having a flat and / or parallel top and bottom surface and forming a cylindrical blank, lapping and rounding are performed. It may include.

[0077] The heat treatment step TT3 includes a temperature maintenance stage, for example, at about 1050°C, particularly between 1000°C and 1200°C, and possibly occurring at the end of the first stage P1.

[0078] Regardless of the embodiment or modification, the second stage of machining P2 may subsequently include various steps for obtaining the final shape of the glass. The second stage P2 particularly includes a truing or grinding step E21 for forming the outer periphery or outer edge 100d of the glass. Step E21 may particularly include substeps or various substeps for obtaining an annular groove or slot 1c, and in specific cases of methods for manufacturing concave glass, a recess 1d. Other steps E22 may enable the formation of a bevel or angle of the glass. A step E23 may also be provided for shrinking and verdigrising the recess in order to dimension the recess 1d.

[0079] The heat treatment step TT2 includes a temperature maintenance stage, for example, at about 1050°C, particularly between 1000°C and 1200°C, and possibly occurring during various steps or substeps of the second stage of machining P2.

[0080] According to a second embodiment of the method, a heat treatment step TT1 including a temperature maintenance stage at approximately 1050°C, particularly between 1000°C and 1200°C, may occur between the second and third stages P2 and P3. In a first embodiment of the method, this step is absent, and a first step TT1 is performed, including a temperature maintenance stage at a temperature higher than 1100°C, particularly between 1600°C and 2000°C. The first stress relief heat treatment step TT1' is, in particular, - Temperatures higher than 1600℃, and / or - Temperatures lower than 2000℃, or lower than 1950℃, or lower than 1800℃, or lower than 1750℃, It may be carried out in this way.

[0081] Regardless of the embodiment or modification, the third stage of finishing P3 may include various brushing or polishing steps, whether chemical polishing or mechanical polishing. For example, the third stage may include a first brushing step E31, which is intended to round off the bevel or the corners of the bevel-forming edge. Various brushing or polishing steps E32 may be provided to obtain a desired surface finish on each of the glass surfaces. The steps may be mechanical polishing, mechanical brushing, or chemical brushing.

[0082] According to a second embodiment of the method, the heat treatment step TT1', which includes a temperature maintenance stage between 1600°C and 200°C, may occur between the two steps E31 and E32.

[0083] Regardless of the embodiment or modification, the manufacturing method advantageously enables the production of sapphire glass, particularly uncolored sapphire glass, i.e., glass that does not undergo a step exclusively dedicated to coloring, as demonstrated by experimental studies conducted by the applicant. Furthermore, regardless of the embodiment or modification, the method relates to any uncolored glass, regardless of its crystal orientation (A or C) and regardless of the method used to obtain it beforehand (Bernoulli, EFG, or Kilopoulos method). The orientation of the sapphire may be type A, i.e., the optical axis is in the plane of the glass or up to 15° away from the plane of the glass. Such a sapphire orientation is preferred for carrying out the Bernoulli method. Alternatively, the orientation of the sapphire may be type C, i.e., the optical axis is perpendicular or substantially perpendicular to the plane of the glass. For such a sapphire orientation, the Kilopoulos and EFG growth methods are preferred.

[0084] Regardless of the embodiment or modification, the glass is preferably cylindrical or circular, but the method can be applied to any other glass shape, such as parallelepiped or rectangular glass.

[0085] The manufacturing method is intended, in particular, to obtain concave glass with optimal mechanical properties.

[0086] Regardless of the embodiment or modification, one, some, or all of the stress relief treatment steps may include a maintenance stage having a duration of several hours, for example, between 2 and 15 hours, typically 5 hours.

[0087] Regardless of the embodiment or modification, one, some, or all of the stress relief treatment steps are performed under a controlled atmosphere, in particular, - Under vacuum, or - Under neutral or inert gas conditions, or - Under a reducing atmosphere, for example, using a reducing gas such as an H2-N2 mixture, or using a neutral or inert gas combined with a graphite heating element that generates carbon monoxide, or - Under an oxidizing atmosphere, for example, under air, It may be implemented.

[0088] As described above, research conducted by the applicant has shown that stress relief heat treatment steps (multiple stress relief heat treatment steps) improve the mechanical properties of glass.

[0089] Embodiments and variations of the methods relating to the present invention, in particular the methods described above, enable the production of clock elements 100, as detailed below. These clock elements 100 can also be obtained by other means.

[0090] In embodiments described in more detail below with reference to Figures 10 and 11, the miniature watch case 400 includes a glass 100, a seal 2, a case 3, and a bezel 4. The glass 100 is preferably machined from a slab of a hard material such as tempered glass, or advantageously sapphire, or more generally clear ceramic. The glass is, - The outer surface 100a, which is intended to come into contact with the external environment, - The inner surface 100b, which is intended to be in contact with the internal volume of the watch case, - An outer edge 100d that connects the outer surface and the inner surface, The outer edge 100d includes a slot 1c. The inner surface includes a recess 1d such that the edge 100d includes a skirt 1f. Thus, the glass 100 has a skirt 1f positioned at the interface between the recess 1d of the glass and the outer edge 100d. The recess 1d may have a recess bottom 1e that is planar, substantially planar, concave, or substantially concave in shape. Preferably, from the recess bottom 1e, the recess 1d has a projection 1h in the skirt 1f, particularly a substantially frustoconical projection. In other words, the portion 1h preferably includes a side wall substantially inclined with respect to the recess bottom 1e. The transition between the recess bottom 1e and the portion 1h has a flat edge 1g. More preferably, the recess bottom 1e of the recess has dimensions, particularly a diameter d1, measured at the base of the flat edge 1g, which is substantially equal to or greater than the opening dimension of the body 3, particularly a diameter d2, particularly at the flange 3b. In other words, the maximum surface area inscribed within the opening dimension d2 is preferably smaller than the surface area of ​​the recess bottom 1e. In other words, the maximum surface area inscribed within the opening dimension d2 can be inscribed on the surface area formed by the recess bottom 1e, or on the projection of the surface area formed by the recess bottom 1e onto a plane parallel to one or the other of these areas. This makes it possible to optimize the readability of the dial and hands by preventing any visual distortion of the dial that tends to occur due to the shape of the skirt 1f through the glass 100.

[0091] When the flange is held by the dial, the opening diameter d2 corresponds to the inner diameter at the base of the dial flange.

[0092] Alternatively, portion 1h may have a side wall substantially straight or perpendicular to the recess bottom 1e, particularly a substantially cylindrical side wall. In another variation, the recess 1d may not include portion 1h and may include only the flat rim 1g. Preferably, the projection of the surface area formed by the flat rim 1g onto a plane parallel to the dial is inscribed within or outside the projection of the surface area of ​​the flange 3b onto the same plane, so that the projection of the surface area of ​​the flat rim 1g along axis A1 does not cover the visible area of ​​the dial.

[0093] In embodiments described in more detail below with reference to Figure 10, the glass 100 includes two portions of different dimensions, particularly different diameters, on its outer edge 100d. The larger portion, particularly the larger diameter portion 1a, is positioned on the outer surface of the small watch case, and the smaller portion, particularly the smaller diameter portion 1b, is positioned on the inner surface of the case once the glass is mounted on the case. A groove 1c or slot 1c, particularly an annular groove 1c, separates portions 1a and 1b.

[0094] The seal 2 has a shape that fits around the glass 100, particularly an annular shape. The longitudinal cross-section of the seal with respect to axis A1 includes a region that extends toward axis A1. This region forms a projection 2a. The seal 2 includes an inner surface 2b intended to cooperate with the glass 100 and the body 3, and an outer surface 2c intended to cooperate with the bezel 4. More specifically, the inner surface 2b cooperates by impact with a portion 1b of the glass 100 and the outer surface 3a of the body 3, which is positioned at substantially the same height as the flange 3b of the body 3. The outer surface 2c cooperates by impact with the inner surface 4a of the bezel 4. Thus, the outer edge 100d, - On the first side of the annular slot 1c is a first portion 1b intended to cooperate with the seal 2, - On the second side of the annular slot 1c, a second part 1a, which is larger in dimensions than the first part 1b, and has a particularly large diameter, Includes.

[0095] The pressing of the bezel 4 into the seal 2 allows the seal 2 to be compressed radially against the glass 100 and the case 3, thereby ensuring that the assembly has optimal strength and water resistance.

[0096] Preferably, the dimensions of the glass portion 1a, particularly the diameter of portion 1a, are very slightly smaller than the dimensions of the outer surface 2c of the seal, particularly the diameter of the outer surface 2c of the seal, such that the seal is largely hidden or covered by the glass (when viewed perpendicular to the glass from the outside). This results in a reduced gap between the glass 100 and the bezel 4 between portion 1a and the inner surface 4a. As a result, the volume of the bezel 4 is advantageously reduced because the bezel does not need to pass over the seal 2 (along an axis parallel to the thickness of the case) to conceal the seal.

[0097] Furthermore, the seal 2 includes projections 2a, particularly annular projections 2a, which are intended to be positioned within a groove or slot 1c in the glass. The projections 2a are advantageously radially extended inward with respect to axis A1. This shape is advantageous in that it allows the glass 100 to be secured to the seal 2, thus ensuring better displacement strength of the seal for the same given radial force on the skirt 1f, for example, when the inside of the case is subjected to higher pressure than the outside. Thus, the glass 100 is held by the seal 2, advantageously by friction, or by fixation or restraint. For this reason, the slot 1c cooperates with the projections 2a of the seal 2 to secure the glass 100, particularly against the bezel 4 and / or body 3.

[0098] The optimized strength achieved by fixing the glass 100 to the seal 2 is advantageous in that it allows for a very small residual wall thickness e2 between the groove or slot 1c and the recess 1d, and a very small radius of the bezel 1g, without compromising the mechanical strength of the glass 100. In particular, for the same displacement strength of the glass, the fixing allows for limiting the radial forces associated with the assembly, thus minimizing the residual wall thickness e2 and enabling a minimum radius of the bezel 1g. For example, the bezel 1g may be on the order of only 0.1 mm, and the thickness e2 may be on the order of only 0.4 mm. The portion 1h preferably has a side wall substantially inclined with respect to the recess bottom 1e, particularly having a frustoconical surface portion, in order to limit stress concentration at the skirt 1f. These dimensions are particularly achievable for small watch cases of a certain size that are resistant to unexpected impacts in accordance with ISO 1413 and NIHS 91-10 standards, and water resistant to pressures up to at least 100 m, i.e., at least 10 bar. For this reason, the skirt 1f may also advantageously have a cross section with a residual wall thickness e3 measured between the portion 1b and the recess 1d that is smaller than the glass thickness e1 measured between the outer surface of the glass and the bottom of the recess 1d, i.e., e3 / e1 < 1.

[0099] In addition, due to the aforementioned fixing, the recess 1d allows for a further reduction in the volume of the miniature watch case. In particular, this solution advantageously allows for obtaining a minimum thickness e1 defined by material strength calculations at the center of the glass 100 without altering the attractive appearance of the miniature watch case on the glass side. As a result, the movement's hands can advantageously be positioned, at least partially, within the recess 1d. This allows for offsetting the movement towards the glass side, and further reduces the thickness of the miniature watch case on the case back side. Advantageously, the fixing and water resistance of the glass 100 are provided to be offset as far as possible toward the case, and the assembly of the bezel 4 is also offset inward, reducing the thickness of the miniature watch case. As a result, the material thickness e5 between the edge of the skirt 1f in part 1b and the groove or slot 1c is advantageously less than the depth e4 of the recess 1d. Thus, the ratio of e5 to e4 is advantageously less than 1, i.e., e5 / e4 < 1.

[0100] In the embodiment shown in Figure 10, the glass 100 is dimensioned to withstand immersion in water to a depth of 100 m with a thickness e1 of 1.3 mm and a recess 1d with a depth e4 of 0.5 mm. The remaining wall thickness between the groove or slot 1c and the recess 1d has a thickness e2 of 0.49 mm. The cross-sectional thickness e3 of the skirt 1f is 0.55 mm and has a flat edge 1g with a radius of 0.3 mm. The ratio of e3 to e1 is equal to 0.42. The thickness e5 is 0.38 mm. Therefore, the ratio of e5 to e4 is equal to 0.76.

[0101] In the embodiment shown in Figure 11, the glass 100 is dimensioned to withstand immersion in water to a depth of 100 m with a glass thickness e1 of 1.3 mm and a recess 1d with a depth e4 of 0.5 mm. The remaining wall thickness between the groove or slot 1c and the recess 1d has a thickness e2 of 0.390 mm. The cross-sectional thickness e3 of the skirt 1f is 0.45 mm and has a flat edge 1g with a radius of 0.6 mm. The ratio of e3 to e1 is equal to 0.35. The thickness e5 is 0.38 mm. Therefore, the ratio of e5 to e4 is equal to 0.76. Compared to the embodiment shown in Figure 10, the skirt 1f does not include a frustoconical portion 1h.

[0102] The two embodiments described include glass having a flat outer surface. However, regardless of the embodiment or modification, the solution is also applicable to glass having a domed outer surface. This is also applicable to the bottom of a recess, which may have a concave or domed surface.

[0103] Regardless of the embodiment or modification, the flat edge 1g may coincide with the bottom 1e of the recess 1d, in which case it has a concave or substantially concave surface extending from the center to the edge of the glass 100.

[0104] Regardless of the embodiment or modification, preferably, seal 2 is - Nylon or polyamide such as polyamide 6 or 6.6, or Zytel® or Grilamid®, or - Thermoplastic elastomers or thermoplastic elastomer copolyesters such as Hytrel (registered trademark), It is made by [manufacturer name].

[0105] The watch element 100, as described with reference to Figures 1, 3, 10, and 11, is a glass intended to allow the dial, or more generally, any display device of the watch, to be seen through it. However, regardless of the embodiment or modification, the watch element 100 may also be a case back glass, i.e., a glass through which the watch movement or any mechanism of the watch movement can be seen. The glass can be mounted directly on the case, or on any intermediate element that allows it to be mounted on the case. As a result, the case back glass can be mounted on a case back, for example, in the form of an annular element that can be mounted on the case.

[0106] The clock element 100 described with reference to Figures 1, 3, 10, and 11 is circular. However, regardless of the embodiment or modification, the clock element 100 may be non-circular. The clock element may, in particular, take the shape of a barrel, or have a substantially rectangular or substantially square shape. As a result, the slot 1c has a similar circular or non-circular shape.

[0107] Regardless of the embodiment or modification, the clock element 100 may include slots 1c all around itself, or it may include slots 1c around some parts whose extent is angularly limited around axis A1, i.e., it may include some cavities. These parts or cavities are preferably, - Uniformly distributed around axis A1, and / or - It can cooperate with the same number of internal protrusions of seal 2.

[0108] Regardless of the embodiment or modification, the clock element 100 is preferably sized to withstand a pressure of at least 10 bar (water resistance up to 100 m), particularly 20 bar (water resistance up to 200 m), or 30 bar (water resistance up to 300 m) applied to its outer surface.

[0109] Regardless of the embodiment or modification, the first thickness e1 measured between the outer surface and the bottom of the recess may be 1 mm or more and 1.5 mm or less, or typically reach about 1.3 mm.

[0110] Regardless of the embodiment or modification, the second thickness e2 measured between the bottom of the slot and the side wall of the recess may be 0.35 mm or more and 0.5 mm or less.

[0111] Regardless of the embodiment or modification, the third thickness e3 of the skirt measured between portion 1b and recess 1d may be 0.4 mm or more and 0.6 mm or less.

[0112] Regardless of the embodiment or modification, the ratio of the third thickness e3 to the first thickness e1 may be less than 1, and may be between 0.3 and 0.5, or typically reach 0.35 or 0.42.

[0113] Regardless of the embodiment or modification, the depth e4 of the recess 1d may be 0.2 mm or more and 0.6 mm or less.

[0114] Regardless of the embodiment or modification, the thickness e5 of the first part 1b may be 0.3 mm or more and 0.4 mm or less, or typically reach about 0.38 mm.

[0115] Regardless of the embodiment or modification, the ratio of the thickness e5 to the depth e4 of the recess 1d may be less than 1, and may be between 0.7 and 0.8, or typically reach 0.76. However, in particular cases where the depth e4 is small, such as about 0.2 or 0.3, the thickness ratio may be greater than 1.

[0116] Regardless of the embodiment or modification, the flat edge 1g may have a radius between 0.1 mm and 0.7 mm, or typically reaching 0.3 mm or 0.6 mm.

[0117] Regardless of the embodiment or modification, the seal 2 is preferably positioned between the bezel and the watch element 100.

[0118] Regardless of the embodiment or modification, the width e6 of the slot, measured parallel to axis A1, may be 0.2 mm or more and 0.5 mm or less.

[0119] Compared to prior art solutions, the solution of the present invention makes it possible to manufacture a small watch case with reduced thickness and no visual distortion, for example, having a seal that is hidden by a glass or bezel protruding thereon.

[0120] The method relating to the present invention provides glass that is resistant to impact and has strength properties that are particularly superior to the very high requirements specified by the applicant. This makes it possible to manufacture thin sapphire glass having recesses. [Explanation of Symbols]

[0121] 1a Second part 1b first part 1c slot 1d recess 1e Recessed bottom 1F Skirt 1g flat edge 1h frustum-shaped section 2 seals 3 Torso 4 Bezels 100 clock elements 100a External surface 100b Inner surface 100d outer edge 300 clocks 400 watch cases

Claims

1. The element (100) of the glass type watch case (400) (300), wherein the element is The outer surface (100a) is intended to come into contact with the external environment, An inner surface (100b) intended to be in contact with the internal volume of the watch case, An outer edge (100d) connecting the outer surface and the inner surface, Includes, The outer edge (100d) includes a slot (1c), and the inner surface includes a recess (1d) such that the outer edge (100d) includes a skirt (1f). element.

2. The aforementioned element (100) is Transparent ceramics, especially transparent polycrystalline ceramics or transparent monocrystalline ceramics, Glass, especially tempered glass, or sapphire, It is made by The element described in claim 1.

3. The aforementioned outer edge (100d) is On the first side of the slot (1c) is a first portion (1b) intended to cooperate with the seal (2), On the second side of the slot (1c), there is a second portion (1a) which is larger in dimensions than the first portion (1b), and in particular has a larger diameter. including, The element according to claim 1 or 2.

4. The second thickness (e2) measured between the bottom of the slot and the side wall of the recess is 0.35 mm or more and 0.5 mm or less. The element according to any one of claims 1 to 3.

5. The third thickness (e3) of the skirt is 0.4 mm or more and 0.6 mm or less. The element according to any one of claims 1 to 4.

6. The ratio of the third thickness (e3) to the first thickness (e1) measured between the outer surface and the bottom of the recess is less than 1, or 0.3 or more and 0.5 or less, typically 0.35 or 0.

42. The element described in claim 5.

7. The ratio of the thickness (e5) of the first portion (1b) to the depth (e4) of the recess (1d) is less than 1, or 0.7 or more and 0.8 or less, typically 0.

76. The element according to any one of claims 1 to 6 and claim 3.

8. The element is obtained by a method including a machining step and a subsequent finishing step, the method further including a first stress relief heat treatment step at a temperature higher than 1100°C after the machining step. The element according to any one of claims 1 to 7.

9. A watch case (400) comprising a watch element (100) according to any one of claims 1 to 8.

10. The bezel (4) and the seal (2) positioned between the bezel and the watch element (100) are included. The watch case (400) according to claim 9.

11. The device includes a case back and a seal (2) positioned between the case back and the element (100), The watch case (400) according to claim 9.

12. The seal (2) is Nylon or polyamide such as polyamide 6 or 6.6, or Zytel® or Grilamid®, or Thermoplastic elastomers or thermoplastic elastomer copolyesters such as Hytrell® It is made by A watch case (400) according to any one of claims 9 to 11.

13. Including the case (3), the slot (1c) cooperates with the projection (2a) of the seal (2) to secure the watch element (100) in particular to the bezel (4) and / or the case (3) and / or the case back. A watch case (400) according to any one of claims 9 to 12.

14. The body (3) includes an opening dimension (d2), particularly an opening diameter (d2), wherein the dimensions of the bottom of the recess, particularly the diameter (d1) of the bottom of the recess, are greater than or equal to the opening dimension (d2), particularly the opening diameter (d2). A watch case (400) according to any one of claims 9 to 13.

15. A clock element (100) according to any one of claims 1 to 8, and / or A watch case (400) according to any one of claims 9 to 14, Including watches (300), especially wristwatches.

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