Patent Application
20150346693
This application claims priority from European Patent Application No. 14171016.0 filed on Jun. 3, 2014, the entire disclosure of which is incorporated herein by reference.
The invention relates to an external part based on photostructurable glass and particularly an external part of this type including at least one photostructurable glass based portion and at least one other silicon, metal or ceramic based portion.
In the field of horology, an increasing number of external parts are formed with the aid of fragile materials such as those based on silicon or ceramic. For example, it is possible to envisage forming the crystal, the bracelet, wristlet or the crown.
However, techniques for etching these fragile materials limit possibilities as regards the possible shapes of external parts.
It is an object of the present invention to overcome all or part of the aforecited drawbacks by proposing an external part which is less limited in regard to shape yet still retains the possibility of using silicon or ceramic based portions.
Hence the invention relates to an external part including a first photostructurable glass based portion, at least a second portion based on at least a second material, characterized in that one surface of the first portion is made integral with a surface of the second portion so as to form a one-piece external part.
Advantageously according to the invention, it is understood that the external part is of the composite type, i.e. it is formed of photostructurable glass and of at least one other material. It is therefore understood that particular shapes can be obtained with the photostructurable glass portion while retaining a functional silicon, metal or ceramic based element.
In accordance with other advantageous variants of the invention:
The invention relates to a timepiece, characterized in that it includes an external piece according to any of the preceding variants.
Further, according to a first embodiment, the invention relates to a method for manufacturing a one-piece external part including the following steps:
According to a second embodiment, the invention relates to a method for manufacturing a one-piece external part including the following steps:
Finally, regardless of the embodiment, several external parts are made on the same substrate for the mass production thereof.
Other features and advantages will appear clearly from the following description, given by way of non-limiting illustration, with reference to the annexed drawings, in which:
As explained above, the invention relates to an external part formed with the aid of a first portion based on photostructurable glass with a second portion including the same type of material or another type of material, i.e. for example based on silicon, metal or ceramic.
This external part was devised for applications in the field of horology and is made necessary by the structuration limitations of fragile materials such as silicon or ceramic based materials. It is possible, for example, to envisage forming a case, a dial, a flange, a crystal, a bezel, a push-button, a crown, a case back cover, a hand or a bracelet or wristlet completely or partially from fragile materials.
However, always having to use ordinary parts, such as, for example, corundum crystals, the production of which is mastered, is a constraint which is difficult to reconcile with the use of parts having no plastic domain.
Hence the invention relates to an external part including a first portion based on photostructurable glass, at least one second portion based on at least a second material, characterized in that one surface of the first portion is made integral with a surface of the second portion so as to form a one-piece external part.
Advantageously according to the invention, it is understood that the first portion will have greater possibilities in regard to shape while retaining a second portion that utilises the advantages of its material. Further, there is a large variety of possible bonding processes for photostructurable glass. Consequently, it is not essential to use additional material to make the two portions integral, as is the case with adhesive bonding or the use of an intermediate part. Thus, for example, two surfaces of corresponding shapes are sufficient to join or bond the first portion with the second portion.
As explained above, the one-piece external part may be completely or partially formed from a basis of photostructurable glass. Thus, said at least one second material may be based on silicon, metal or ceramic. Further, said at least one second material may also optionally include an intermediate material intended to promote the bonding of two materials that are difficult to attach. Thus, depending on the bonding technique selected, this intermediate material may be likened to a braze intended to attach two materials to each other by joint adherence to the intermediate material, or form a layer intended to produce sufficiently intense heat to cause the two materials to melt.
When said at least one second material is silicon-based, it may include single crystal silicon, doped single crystal silicon, polycrystalline silicon, doped polycrystalline silicon, porous silicon, silicon oxide, quartz, silica, silicon nitride or silicon carbide.
When said at least one second material is ceramic-based, it may include photostructurable glass, borosilicate, aluminosilicate, quartz glass, zerodur, single crystal corundum, polycrystalline corundum, alumina, aluminium oxide, aluminium nitride, single crystal ruby, polycrystalline ruby, zirconium oxide, titanium oxide, titanium nitride, titanium carbide, tungsten nitride, tungsten carbide, boron nitride or boron carbide.
When said at least one second material is metal-based, it may include an iron alloy like 15P, 20AP or 316L steels, a copper alloy such as brass, a nickel alloy such as nickel silver, titanium or an alloy thereof, gold or an alloy thereof, silver or an alloy thereof, platinum or an alloy thereof, ruthenium or an alloy thereof, rhodium or an alloy thereof, or palladium or an alloy thereof.
Further, said at least one second material, even based on silicon, metal or ceramic, may include at least a partial coating of silicon oxide, silicon nitride, silicon carbide or an allotrope of carbon.
Advantageously according to the invention, the first portion and/or the second portion may form a large variety of external parts for a timepiece. By way of non-limiting example and with reference to
By way of example,
It is understood therefore, for example, that dial 22 may be integral via its contact surfaces 28, 29, 30, 31, 32 with appliques 23, 24 and/or decoration 25 and/or feet 2627, the photostructurable glass based portion being formed by dial 22 and/or appliques 23, 24 and/or decoration 25 and/or feet 26, 27. Of course, other types of contact surface may be provided, such as sloping surfaces or non-rectilinear surfaces.
As explained above, the first portion and/or the second portion may form a variety of external parts. By way of additional example in
Further, a first portion could form a crystal 14 and be integral with a second portion forming a bezel 5 or a magnifying glass, a first portion could form a push-button 6 and be integral with a second portion forming a push-button arbor, a first portion could form a crown 7 and be integral with a second portion forming a winding stem, a first portion could form a case back cover 8 and be integral with a second portion forming a crystal intended to show the timepiece movement, a first portion could form a bracelet attachment link and be integral with a second portion forming a clasp or a first portion could form a bracelet link 11 and be integral with a second portion forming a counter-link.
According to a first preferred embodiment, the invention relates to a manufacturing method including a first step a) intended to provide a first wafer 51 based on photostructurable glass including a first etched pattern 53 as shown in
Advantageously according to the invention, photostructuration of a photostructurable glass allows for a greater variety of shape than etching of silicon or ceramic based materials. The photostructuration process consists, in a first phase, of illumination at a wavelength corresponding to photostructurable glass through a mask that is partially opaque to said wavelength. Areas of the photostructurable glass wafer are structured according to the quantity, orientation and distribution of illumination.
It is thus understood that by using a mask with areas of variable opacity and/or a source with controllable focus, it is possible to create shapes such as the aforementioned appliques 23, 24. The illumination source may for example by a UV lamp with a spectral distribution peak at a wavelength comprised between 200 and 400 nm.
A second phase consists in subjecting the photostructurable glass wafer to a heat treatment. The heating temperature varies according to the photostructurable glass and may be up to approximately 600° C. This heat treatment makes more selective illuminated areas for the last elimination phase by a chemical etching. This chemical etching may be performed, for example, in a 10% hydrofluoric acid bath, at ambient temperature and using ultrasounds. A wafer 51 as shown in
A second step b) is intended to provide at least a second wafer 55 made of at least a second material including at least a second etched pattern 57 as shown in
A third step c) is intended to join or bond first wafer 51 with said at least one second wafer 55 to form a one-piece substrate and, by superposition of said patterns 53, 55, to form a one-piece external part including a first thickness based on photostructurable glass and at least a second thickness of said at least one second material based on silicon, metal or ceramic.
Depending on the materials used, there are several possible bonding methods. In a non-limiting manner, one may mention the direct welding of surfaces by electromagnetic radiation using a laser, as, for example, explained in EP Patent No 1436830, which is incorporated by reference in this description. It is also perfectly possible to envisage using anodic bonding, fusion bonding, thermocompression bonding, reflow bonding, eutectic bonding, ultrasonic bonding or thermosonic bonding.
Finally, the method includes a final step d) intended to release the one-piece external part from the substrate. Advantageously according to the invention, a large variety of materials can thus be used to form external parts in an industrial manner.
As illustrated in
According to an alternative of the first embodiment, step b) may consist in forming several second wafers formed from the same material or from several different materials. In this alternative of the first embodiment, it is therefore understood that in step c) it is possible to obtain a one-piece substrate with three bonded wafers thus forming an external part including a first thickness based on photostructurable glass forming the body of dial 22 and at least two second thicknesses formed from the same material or from several different materials forming the appliques 23, 24 and feet 26, 27 of the dial.
According to a second embodiment, the invention relates to a manufacturing method including a first step e) intended to join or bond a first photostructurable glass based wafer with at least a second wafer made of at least a second material to form a one-piece substrate with the aid of the same methods described in step c) of the first embodiment.
The second embodiment continues with step f), intended to etch a pattern in each of the wafers of the substrate and, by superposition of said patterns, to form a one-piece external part including a first thickness based on photostructurable glass and at least one second thickness of said at least one second material with the aid of the same methods described in steps a) and b) of the first embodiment.
Finally, the method includes a final step g) intended to release the one-piece external part from the substrate. Advantageously according to the invention, a large variety of materials can thus be used to form external parts in an industrial manner.
As illustrated in
According to an alternative of the second embodiment, similar to that of the first embodiment, step e) may also consist in making a substrate with the aid of several second wafers formed from the same material or from several different materials. In this alternative of the second embodiment, it is therefore understood that it is possible to obtain a substrate with three bonded wafers thus forming an external part including a first thickness based on photostructurable glass and at least two second thicknesses formed from the same material or from several different materials as for the first embodiment.
Of course, regardless of the embodiment, the method permits several external parts 61 to be manufactured on the same substrate 63 as illustrated in
The present invention is not limited to the illustrated example but is capable of various variants and modifications which will be clear to those skilled in the art. In particular, if the same pattern is required for each portion, the wafers may be bonded to each other and then a single etching may be provided.
Likewise, as in the example of the multiple appliques 13, 23, 24 of dial 4, 22, the method using wafers is preferred, i.e. all of appliques 13, 23, 24 are structured in the same photostructurable glass wafer and made integral with another wafer. However, there is nothing to prevent appliques 13, 23, 24 from being detached one-by-one and then gradually made integral with another finished part, such as dial 4, 22.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14171016.0 | Jun 2014 | EP | regional |
