阅读说明：本技术 着色的表玻璃 (Coloured watch glass ) 是由 玛丽亚-伊莎贝尔·博尔格斯-马查多 亚历山德拉·鲁莱 于 2020-02-17 设计创作，主要内容包括：本发明提供一种透明的钟表部件,特别是表玻璃,其中该钟表部件包括基本上平面或弯曲的内部表面,并且其中该钟表部件主要包括透明材料,该透明材料通过引入该透明材料的至少一种着色化学元素而通过在该部件内的化学成分改变区域来着色,该化学成分改变区域仅在钟表部件的总厚度的一部分中延伸。(The invention provides a transparent timepiece component, in particular a watch glass, wherein the timepiece component comprises a substantially planar or curved internal surface, and wherein the timepiece component essentially comprises a transparent material which is coloured by a chemical composition changing region within the component by introducing at least one colouring chemical element of the transparent material, the chemical composition changing region extending only in a portion of the total thickness of the timepiece component.)

1. A transparent timepiece component, in particular a watch glass, wherein the timepiece component comprises a substantially planar or curved interior surface, and wherein the timepiece component essentially comprises a transparent material that is coloured by a chemical composition changing area within the component that extends only in a portion of the total thickness of the timepiece component via the introduction of at least one colouring chemical element into the transparent material.

2. The timepiece component according to the preceding claim, wherein the chemical composition changing region extends over a thickness which is, on average, at most 25%, including 25%, or even at most 2%, including 2%, or even at most 0.2%, including 0.2%, or even at most 0.07%, including 0.07%, of the total thickness of the timepiece component.

3. The timepiece component according to any one of the preceding claims, wherein the chemical composition changing area extends over a thickness which is at least 0.0002% of the total thickness of the timepiece component on average.

4. The timepiece component according to any one of the preceding claims, wherein the colorless or previously colored transparent material is an inorganic and/or mineral material, such as synthetic single crystal alumina or sapphire or corundum, or wherein the transparent material is a material at least partially composed of an inorganic substance and/or mineral, such as glass, corundum, alumina, a Yttrium Aluminum Garnet (YAG) -based material, a glass ceramic and/or a single crystal or polycrystalline ceramic.

5. Timepiece component according to any one of the preceding claims, wherein at least one coloring chemical element is chosen from metals, and/or metal oxides, and/or metal compounds, and/or metal alloys, and/or transition metals, and/or transition metal oxides, and/or metalloids, and/or non-metals, and/or gases.

6. Timepiece component according to any one of the preceding claims, wherein at least one coloring chemical element is chosen from cobalt, and/or iron, and/or chromium, and/or gold, and/or titanium, and/or vanadium, and/or copper, and/or manganese, and/or magnesium, and/or zinc, and/or silver, and/or boron, and/or nitrogen.

7. The timepiece component according to any one of the preceding claims, wherein the chemical composition changing region comprises cobalt aluminate and/or cobalt in order to obtain a blue and/or green timepiece component, or wherein the chemical composition changing region comprises gold in order to obtain a pink or red timepiece component.

8. Timepiece component according to any one of the preceding claims, wherein the timepiece component has an area greater than or equal to 20mm²And a thickness greater than or equal to 0.85 mm.

9. The timepiece component according to any one of the preceding claims, wherein the timepiece component is a watch glass having an area greater than or equal to 80mm²Or even greater than or equal to 200mm²Or even greater than or equal to 300mm²And a thickness greater than or equal to 0.2mm and/or less than or equal to 15 mm.

10. Timepiece component according to claim 8 or 9, wherein the timepiece component is transparent so as to allow reading of an indication, in particular a time indication, through its thickness and optionally allowing charging and/or discharging of a photoluminescent material through its thickness, and/or wherein the timepiece component comprises a transmission coefficient (Y) greater than or equal to 68%.

11. Timepiece component according to any one of the preceding claims, wherein the timepiece component is a timepiece glass comprising an external surface and comprising a side surface inclined with respect to the external surface, the inclination of the side surface with respect to a direction perpendicular to the internal surface being greater than or equal to 10 °, or even greater than or equal to 15 °, or even greater than or equal to 30 °, in order to adjust the coloring effect of the timepiece glass, and/or wherein the timepiece component comprises a raised and/or indented structured area on at least one surface of the timepiece component and/or a structured area within the thickness of the timepiece component.

12. The timepiece component according to any one of the preceding claims, wherein the inclined side surface is between 1% and 30% of the area of the inner surface, or even between 1% and 18% of the area of the inner surface, or even between 10% and 18% of the area of the inner surface.

13. The timepiece component according to any one of the preceding claims, wherein the timepiece component includes all or some of the following features:

a. the chemical composition changes the thickness gradient of the area in order to adjust the coloring effect of the timepiece component; and/or

b. The chemical composition changes the discontinuity of the area, particularly the forming feature.

14. Timepiece, wherein the timepiece comprises a timepiece component according to any one of the preceding claims.

15. A method of manufacturing a coloured and transparent timepiece component, wherein the manufacturing method comprises the steps of:

a. providing (E0) an initial substrate consisting essentially of a transparent material and comprising a substantially planar or curved interior surface;

b. introducing (E1) at least one coloring chemical element through at least one external or internal surface of said initial substrate;

c. heat-treating (E2) the substrate obtained from the introduction step (E1) comprising at least one colouring chemical element, so as to obtain a transparent and coloured component.

16. Method for manufacturing a timepiece component according to any one of the preceding claims, wherein the step of introducing (E1) includes a step of depositing a coating including at least one coloring chemical element on at least one surface of the initial substrate, in particular Physical Vapor Deposition (PVD) by Magnetron Sputtering (MS) and/or thermal evaporation, and/or by Atomic Layer Deposition (ALD), and/or by Chemical Vapor Deposition (CVD), and/or wherein the step of introducing (E1) includes a step of recoil ion implantation of the at least one coloring chemical element.

17. The method of manufacturing a timepiece component according to any one of the preceding claims, wherein the timepiece component is a watch glass, and wherein the step of introducing (E1) includes a step of depositing a coating having a thickness between 1nm and 10 μm, inclusive, or even between 1nm and 1 μm.

18. The method of manufacturing a timepiece component according to any one of claims 15 to 17, wherein the step of introducing (E1) includes a step of depositing a coating and a preceding step consisting in masking the surface of the substrate so as to prevent it from receiving the coating and/or so as to form a coating of variable thickness.

19. The manufacturing method of a timepiece component according to any one of claims 15 to 18, wherein the heat treatment step (E2) includes a holding temperature between 500 ℃ and 1850 ℃ or even between 800 ℃ and 1400 ℃ or even between 900 ℃ and 1200 ℃ for a duration of between 0.5 and 48 hours or even between 0.5 and 4 days.

20. A method of manufacturing a timepiece component according to any one of claims 15 to 19, wherein the method of manufacturing includes all or some of the following additional steps:

a. processing the transparent and coloured component so as to form a timepiece part; and/or

b. Machining at least one surface of the transparent and coloured component to change its shape and/or form features and/or form side surfaces inclined with respect to the external surface of the timepiece part, the inclination of said side surfaces with respect to a direction perpendicular to the internal surface being greater than or equal to 10 °, or even greater than or equal to 15 °, or even greater than or equal to 30 °, in order to adjust the colouring effect of the timepiece part; and/or

c. Assembling the transparent and coloured component with another timepiece part; and/or

d. Removing residues of the coloring chemical elements from the surface of the transparent and colored member, particularly by chemical peeling or mechanical action such as polishing; and/or

e. Etching features on the timepiece component.

Technical Field

The invention relates to a transparent and coloured timepiece part, in particular a watch glass. The invention also relates to a timepiece, such as a watch, comprising such a timepiece component. The invention also relates to a method for manufacturing a timepiece component, comprising in particular a stage of colouring a transparent substrate.

Background

Watch glasses made of sapphire are transparent and colorless in nature, and it is sometimes desirable to color them to change their appearance. For this reason, there is a method of coloring sapphire while synthesizing it. This method produces a sapphire ball that is colored throughout, and the table glass is then cut from the sapphire ball. This method is described, for example, in document WO 2017/187647. This prior art solution has a number of disadvantages:

it requires complex studies each time the color is changed;

it is not possible to color the part partially, nor to combine several colors;

it is not compatible with certain colors that cannot be obtained or rendering of insufficient quality; it may therefore be incompatible with a timepiece application.

In addition to the above description, it should be pointed out that any manufacturing method of a timepiece component must comply with a number of constraints and that modifications to the process of integrating the colouring step must not reduce the overall quality of the timepiece component obtained. For example, for watch glasses, the following watch requirements must be observed:

the glass must have sufficient transparency to enable time to be read;

glass must have high overall mechanical strength and must also have surface scratch resistance;

the colour of such glasses must be such as to enable predictable and repeatable results;

the perceived color must have a quality rendering that is defect free, perfectly homogeneous or exactly inhomogeneous according to a predetermined selected distribution;

the colour obtained must be suitable for a watch, in particular for a watch dial that can be seen through glass.

These technical problems also apply to other transparent timepiece components, in particular timepiece components having a substantially planar shape, in particular having a substantially planar or curved internal surface and/or made of a mineral material such as sapphire or glass.

The general object of the present invention is to obtain a solution for obtaining a transparent and coloured timepiece component that does not present all or some of the drawbacks of the prior art.

More specifically, the aim of the invention is to obtain a transparent and coloured timepiece-part solution that can achieve a high-quality repeatable and precise visual appearance.

Disclosure of Invention

To this end, the invention is based on a transparent timepiece component, in particular a watch glass, wherein the timepiece component comprises a substantially planar or curved internal surface, and wherein the timepiece component essentially comprises a transparent material which is coloured by a chemical composition changing region within the component by introducing at least one colouring chemical element into the transparent material, the chemical composition changing region extending only in a portion of the total thickness of the timepiece component. Advantageously, the chemical composition change zone does not extend in the entire volume of the timepiece component. More advantageously, it does not extend over its entire thickness. More advantageously, it extends over a small portion of its thickness and/or of its volume.

The invention also relates to a method for manufacturing a coloured and transparent timepiece component, wherein the manufacturing method comprises the following steps:

a. providing an initial substrate comprising a substantially planar or curved interior surface consisting essentially of a transparent material;

b. introducing at least one coloring chemical element through at least one external or internal surface of the initial substrate;

c. the substrate obtained from the introduction step, comprising at least one colouring chemical element, is subjected to a heat treatment in order to obtain a transparent and coloured component.

Advantageously, the step of introducing comprises depositing a coating comprising at least one colouring chemical element.

The invention is more particularly defined by the claims.

Drawings

These objects, features and advantages of the present invention will be set forth in detail in the following description of particular embodiments thereof, given in a non-limiting manner with reference to the accompanying drawings, in which:

fig. 1a to 1e schematically show cross-sectional views of the thickness of a substrate that is a precursor of a timepiece component, according to a number of variants of embodiments of the invention.

Fig. 2a and 2b schematically show a cross-sectional view of the thickness of a base material that is a precursor of a timepiece component, after a first manufacturing step and a second manufacturing step of a manufacturing method according to an embodiment of the invention have been carried out in sequence, respectively.

Fig. 3a shows a comparison of the transmission (T) as a function of the wavelength (L) of various glasses made of sapphire according to the first example, obtained by different variants of the manufacturing method according to an embodiment of the invention.

Fig. 3b is an enlarged view of the box portion in fig. 3 a.

Fig. 3c shows an image taken with a Transmission Electron Microscope (TEM) of a thin section taken from the finally colored transparent member achieved in the manufacturing method according to the embodiment of the present invention. The inset shows an electron diffraction image taken in a region close to the surface (at a distance from the surface less than distance d).

Fig. 4 shows the transmittance (T) as a function of wavelength (L) of various sapphire glasses according to a second example, obtained by different variations of the manufacturing method according to the embodiment of the present invention.

Fig. 5 shows the transmittance (T) as a function of wavelength (L) of various sapphire glasses according to a third example, obtained by different variations of the manufacturing method according to the embodiment of the present invention.

Fig. 6a to 6c show the transmittance (T) as a function of the wavelength (L) of various sapphire glasses according to a fourth example, obtained by different variations of the manufacturing method according to the embodiment of the present invention.

Fig. 7 shows the transmittance (T) as a function of the wavelength (L) of various sapphire glasses according to a fifth example, obtained by different variations of the manufacturing method according to the embodiment of the present invention.

For the sake of clarity of description, the same reference numerals will be used for different embodiment variants to indicate the same or equivalent features.

Detailed Description

Furthermore, to simplify the following description, the adjective "external" will denote a volume or surface of a timepiece component intended to face the exterior of the timepiece, including in particular a volume or surface directly visible to an observer looking at the timepiece. Instead, the adjective "internal" will denote the volume or surface of the timepiece component intended to face the interior of the timepiece. Inappropriately, the use of the adjectives "external" and "internal" would extend to the components placed completely inside the timepiece, whose external surface is then the one that might be positioned closest to the external limits of the timepiece.

Furthermore, the adjective "transparent" will be used to indicate the property of the material in question when it produces a transmittance, evaluated by the transmission coefficient Y, which is greater than 68% (including 68%) or even greater than 79% (including 79%) of a light radiation including at least wavelengths in the visible range. The term "transparent material" will be understood to mean a material whose properties, combined with the thickness used, allow at least partial transmission of the above-mentioned optical radiation. Advantageously, the transparent material used also allows at least partial transmission of radiation comprising wavelengths in the ultraviolet range.

An embodiment of the method of manufacturing sapphire glass for a timepiece of the invention will now be described. This same method will be applicable to other timepiece components, as will be explained in detail in the rest of the text. The manufacturing method comprises the following two main steps forming a colouring stage or colouring process after the previous step of providing (E0) a transparent substrate (i.e. a substrate mainly comprising a transparent material):

-introducing (E1) at least one colouring chemical element on at least one external or internal surface of the provided substrate (also called initial substrate);

-heat treatment (E2) of the substrate comprising at least one colouring chemical element resulting from the introduction step, in order to obtain a transparent and coloured component.

As described above, the method performs the previous step of providing (E0) an initial substrate 10. The substrate advantageously has a substantially planar shape comprising an outer surface intended to face towards the outside of the timepiece and a substantially planar or curved inner surface intended to face towards the inside of the timepiece. Advantageously, the substrate is made entirely of transparent material. The transparent material may be colorless. As a variant, it may be coloured. However, the method may be applied to transparent portions of a substrate that are only partially transparent.

In this embodiment, the transparent material is sapphire, more specifically synthetic single crystal alumina. As a variant, the material may be any other transparent material at least partially composed of inorganic and/or mineral substances, such as glass (borosilicate, photostructurable glass, etc.), corundum, alumina, Yttrium Aluminum Garnet (YAG), glass-ceramic and/or monocrystalline or polycrystalline ceramic. The transparent material may also be coloured alumina or any other transparent material as described above which has been coloured beforehand.

The initial substrate additionally advantageously has the same shape or even a similar shape as the future glass, which can be altered by subsequent steps (e.g., processing). The substrate additionally advantageously has the same surface finish as future glass. The outer and/or inner surfaces thereof are preferably polished. As a variant, it may have another surface finish, in particular locally.

The outer and/or inner surfaces may be planar. As a variant, it may be curved, for example concave or convex. It may be curved and preferably continuous, that is to say not consisting of juxtaposed facets. However, it may comprise a bevel or a chamfer, in particular at the level of its peripheral portion, as will be explained in detail later.

As a variant, at least one internal or external surface may comprise features which may particularly represent a time indication or an indication derived from time, such as raised and/or indented structured zones (structured zones) formed by machining.

Fig. 1a to 1e show examples of substrates (referred to as initial substrates) proposed in a previous step for the manufacture of watch glasses according to a number of implementation variants.

Thus, fig. 1a shows an initial substrate 10 according to a first variant, comprising a planar outer surface 2 forming a plane P2, parallel to a planar inner surface 1 forming a plane P1. The substrate also comprises a side surface 3 at the periphery, which forms a flat cylindrical third surface extending perpendicularly to the outer surface 2 to the inner surface 1 around the entire periphery of the substrate. The total thickness e of the initial substrate is defined as the distance between the outer surface 2 and the inner surface 1. In particular, the total thickness e is measured perpendicular to the inner surface 1 in a direction P perpendicular to the plane P1, in particular perpendicular to the planes P1, P2. Of course, the substrate may have any shape, advantageously corresponding to the future timepiece on which it is to be mounted, for example circular, oval, rectangular, etc. Advantageously having an internal surface with an area greater than or equal to 20mm for the manufacture of a single lens or magnifier²Or for the manufacture of watch glass, the area of the internal surface being greater than or equal to 80mm²Or even greater than or equal to 200mm²Or even greater than or equal to 300mm²。

Fig. 1b shows an initial substrate 10 according to a second variant, which differs from the substrate of the first variant in that the lateral surface 3 comprises a portion 4 formed with a chamfer at the periphery of its outer surface 2. The ramp portion 4 is truncated and extends between the outer surface 2 and the rest of the side 3 (between the plane P2 and an intermediate plane P3 parallel to the plane P2). The rest of the side 3 is still perpendicular to the inner surface 1. Advantageously, the beveled portion extends around the entire periphery of the substrate. The bevel portion 4 extends over a thickness f of the substrate measured perpendicularly to the planes P2, P3, which corresponds approximately to slightly less than half the total thickness e of the substrate. Preferably, the thickness f is between 0.07 and 0.6 times the total thickness e of the substrate. The ramp portion 4 forms a constant angle alpha with the direction p. Advantageously, the angle α is between 30 ° and 80 °. Alternatively, the angle α and/or the thickness f may vary around the circumference of the glass.

Fig. 1c shows a starting substrate 10 according to a third variant, which forms an intermediate solution between the two variants described above. The at least partly planar side 3 is replaced by a curved side 3 connecting the two surfaces, the outer surface and the inner surface, by a continuous curve. The curve forming the side 3 can be characterized at each point by an angle α defined by the angle between the tangent of the curve and the direction p. The angle α is variable but remains greater than 30 ° over the first portion of the side 3 on the side of the outer surface 2. The remaining part of the curve forming the side 3 on the side of the inner surface 1 may be perpendicular or substantially perpendicular to the inner surface 1 at an angle alpha equal to 0 deg. or tending towards 0 deg.. This first portion of the side 3 is similar to the beveled surface 4 of the second variant.

Fig. 1d shows an initial substrate 10 according to a fourth variant, in which both the external surface 2 and the internal surface 1 are curved in one and the same parallel shape. The outer wall is symmetrically disposed about the central axis and the apex is defined as the outermost point of the outer surface 2 and the plane P2 is a plane tangent to the curved outer surface 2 and passing through the apex. Thus, the plane P2 corresponds to the outermost plane of the outer surface 2. Likewise, the innermost point of the interior surface 1 (that is, the point defining the periphery of the interior surface) may define a plane P1 that is tangential to the interior surface 1 and parallel to the plane P2. The direction P is defined as the direction perpendicular to the plane P1, in particular perpendicular to the planes P1, P2. Thus, the total thickness e of the substrate, measured perpendicular to the plane P1 along the direction P, remains defined as the distance between the two planes P1, P2. The side face 3 constitutes an outer peripheral surface connecting both surfaces. The side 3 comprises at the level of the outer surface 2a curved first portion 4, which curved first portion 4 extends through a portion perpendicular to the planes P1, P2 to the inner surface 1. The curved first portion 4 extends as a whole between planes P2 'and P3 parallel to planes P1, P2 and has a thickness f, measured perpendicularly to planes P2', P3, strictly less than the total thickness e. Alternatively, a substrate having a planar inner surface 1 and a geometric standard which is also equivalent to the geometric standard of fig. 1d can be envisaged.

Fig. 1e shows an initial substrate 10 according to a fifth variant, in which the two surfaces, the external surface 2 and the internal surface 1, are planar and parallel. The side 3 comprises a first portion corresponding to the bevel 4 (similar to the first portion of the second variant) and a second portion comprising a groove. The side surfaces also include rounded corners.

In any case, the total thickness e of the initial substrate 10, and therefore of the surface glass, is comprised between 0.2mm and 15mm, or even between 0.85mm and 15mm, or even between 1.45mm and 11 mm. Moreover, an angle α of the side 3 of greater than or equal to 10 °, preferably greater than or equal to 15 ° or even greater than or equal to 30 °, allows to achieve visual effects corresponding to the chromatic adjustment, whatever the geometry of the glass. Furthermore, regardless of the geometry of the glass, the specific portion 4 of the side 3 may have a variable area compared to the area of the internal surface 1, and may be between 1% and 30% of the internal surface 1, or even between 1% and 18% of the internal surface 1, or even preferably between 10% and 18% of the internal surface 1.

When a substrate is provided at the end of this previous step, the manufacturing method then performs two main steps of the method, which form the initial substrate colouring stage.

The first step consists in introducing (E1) at least one colouring chemical element.

According to a first variant embodiment, this introduction is carried out by depositing on at least one of the two internal or external surfaces of the initial substrate a coating comprising at least one colouring chemical element. To this end, the coating may be deposited by one of the following methods:

-Physical Vapour Deposition (PVD), in particular Magnetron Sputtering (MS); or

Physical Vapour Deposition (PVD), in particular thermal evaporation; or

-Chemical Vapour Deposition (CVD); or

-Atomic Layer Deposition (ALD); or

-liquid deposition of spin-coating, dip-coating or sol-gel type.

In a second embodiment variant, the introduction is carried out by recoil ion implantation, in particular in the case where the diffusion of the coloring chemical element introduced in the form of a coating in the substrate is slow or requires too high a temperature. The term "recoil ion implantation" is intended to mean the deposition of a thin coating consisting of at least one coloring chemical element by PVD, CVD and/or ALD combined with ion implantation of the coating by bombardment with a gas such as argon and/or nitrogen and/or oxygen.

In these variants in which at least one colouring chemical element is introduced, a coating is formed on at least one surface of the initial substrate, in particular on at least one of the external or internal surfaces. The coating may be uniform or may comprise a superposition of layers consisting of various elements. Fig. 2a shows the results obtained after introducing the coating 20 on the inner surface 1 of the substrate. This step makes it possible to deposit the coating thickness e' very precisely. The coating thickness e' can be between 1nm and 10 μm, in particular between 1nm and 1 μm. This thickness e' may define the future color and may also define the transparency of the resulting tinted transparent member, in particular a watch glass. Therefore, there will be a trade-off. Too small a coating thickness to allow for coloration; this defines the lower limit of the thickness e'. The thickness is too large to maintain sufficient transparency of the substrate. This defines an upper limit for the thickness e'. The thickness range depends on the coloring chemical element, the transparent material of the substrate, and the heat treatment to be applied as described in detail below.

Furthermore, the coating may be uniform, that is to say of constant thickness over the entire surface of the substrate, in order to obtain uniform results. As a variant, it may be desirable to obtain non-uniform results; in this case, the coating may be uneven.

For example, the coating may be discontinuous. To this end, the method comprises a preceding step consisting in depositing a mask, for example a resin, on the surface or surfaces to which the coating is introduced, so as to obtain a partial coating only outside the mask area. Next, after the coating is applied, the mask is removed. The mask may be more or less dense so as to form a color gradient according to the mask density.

An alternative approach might consist in coating the surface of the substrate without taking the features into account and selectively removing layers to map the features.

Deposition of coatings of variable thickness can be achieved, for example, by a directional vacuum method such as MS PVD deposition. The thickness gradient of the coating 20 may be obtained by tilting the substrate during deposition or by means of a suitable mask or any other suitable method.

Alternatively, the at least one coloring chemical element may be introduced by direct ion implantation without involving a coating. The latter alternative has the disadvantage that it is difficult to control the amount of colouring chemical elements that may be introduced into the substrate and to obtain a precise definition of the features through the mask.

Preferably, the introduction of the at least one colouring chemical element is carried out on a single internal or external surface of the substrate. As a variant, this introduction can be carried out on both the internal and external surfaces or even on all or part of the side 3.

The colouring chemical elements may be selected from the following non-exhaustive list:

-a metal element, in particular a metal element selected from transition metals; or

-oxides, in particular metal oxides formed from transition metals; or

-a metal alloy; or

-a metalloid, a non-metal or a gas.

The coloring chemical elements are combined with the material of the substrate to obtain the desired color. In particular, for the blue coloration of alumina substrates, the use of cobalt is a known practice. Of course, coloring elements such as iron, titanium, gold, chromium, vanadium, copper, manganese, magnesium, zinc, silver, boron, nitrogen, etc. may be used alone or in combination to achieve other colors. Thus, several different elements may be combined, for example several colouring chemical elements in the above list. For example, the addition of chromium or gold to alumina may produce a red color, while the combined addition of titanium and iron may produce a blue color.

It should be noted that the method advantageously comprises a step of cleaning the substrate before the step of introducing the one or more colouring chemical elements. Cleaning may include detergent washing followed by one or more rinsing operations and one or more drying operations.

Next, the method comprises a second main step E2 of carrying out a heat treatment of the substrate obtained from the introduction step E1, comprising at least one colouring chemical element. The heat treatment comprises the following steps: the substrate resulting from the previous step is heated and then held at the holding temperature for a holding period of time before the step of cooling the substrate.

The maximum holding temperature is particularly important for performing the function of transferring one or more colouring chemical elements into the initial substrate. The length of the holding time can have an influence on the amount of already diffused and/or already reacted colouring chemical elements, so that a somewhat intense final colour is set. Therefore, the time period can be selected according to a very wide range. Finally, the rate of temperature change is of secondary importance in the colouring function and will be chosen to avoid any attack on the initial substrate, in particular to avoid any thermal shock.

Advantageously, the temperature is maintained between 500 ℃ and 1850 ℃, or even between 800 ℃ and 1400 ℃; more particularly, in the case of the initial substrate comprising a cobalt coating made of single-crystal alumina resulting from the introduction of step E1, the temperature is maintained between 900 ℃ and 1200 ℃. The associated hold duration may be long (up to several days); for the particular case of a starting substrate comprising a cobalt coating made of monocrystalline alumina obtained at the end of step E1, the duration of the hold is advantageously between 0.5 and 48 hours, or even more generally between 0.5 and 4 days.

The heat treatment may be carried out in ambient air. According to a variant, it is carried out in a controlled inert, oxidizing or reducing atmosphere or even under vacuum. In particular, the heat treatment may be performed under a nitrogen atmosphere. According to other variations, the gas flow rate and pressure may be varied. Furthermore, this second heat treatment step E2 may be carried out in a second apparatus different from the first apparatus provided for carrying out the first introduction step E1. Alternatively, this second step E2 may be carried out in the same equipment as used for the first introduction step E1.

Fig. 2b schematically shows the results obtained after heat treatment of the substrate obtained in the first step represented in fig. 2 a. At the end of the heat treatment, near the inner surface 1, a chemically altered area 30 of thickness d is obtained within the volume of the substrate. The region of altered composition performs a coloring function. For example, the composition which is initially colorless and transparent is Al₂O₃Can be modified by formation of CoAl by metered addition of cobalt₂O₄Can be changed to blue and/or can be changed to green by the addition of cobalt in a metered amount to form a region of changed composition by substitution of cobalt in the alumina. According to another example, alumina Al₂O₃Magnesium is added to obtain magnesium aluminate MgAl₂O₄. According to yet another example, alumina Al is added₂O₃The addition of gold can achieve coloration by the plasma effect. Coloring by the formation of intermetallic compounds is also conceivable. This step completes the conversion of the initial substrate into a transparent and colored member. The chemical composition-altering regions 30 are therefore coloured and surprisingly produce the same visual effect as glass which has been coloured throughout its volume and therefore throughout its thickness. However, the chemical composition-change zone extends only over a very small thickness d of between 30 and 500nm, which, in the case of colouring on a single internal or external surface, is on average at most 25% (including 25%), or even at most 2% (including 2%), or even at most 0.2% (including 0.2%), and preferably at most 0.07% (including 0.07%) of the total thickness e of the timepiece component. Thus, formed therebyThe transparent and colored component always consists mainly of a transparent material originating from the starting substrate 10 and a small amount of chemically modified and colored transparent material.

By the process thus carried out, a transparent and coloured component is obtained which does not require any further finishing of its surface finish or even of the treated surface. In fact, the thickness e' of the coating formed by one or more colouring chemical elements may be provided in the following way: the one or more coloring chemical elements completely diffuse into the substrate 10 and/or completely react with the substrate 10 during the heat treatment. Potentially, since the process can be implemented in such a way that the entire amount of the coloring chemical element is consumed by the process during the heat treatment, it is not necessary to remove the excess coloring chemical element. Alternatively, any residue of the coloring chemical element on the surface of the member may be removed by any means known to those skilled in the art (stripping, dissolving, chemical etching, polishing, etc.) if desired.

At the end of this second step, the method may comprise a step of finalizing the timepiece component, in particular the watch glass. For example, if the starting substrate is not a finished watch glass, for example, which does not have the desired shape, it can be obtained by working the obtained transparent and tinted member, in particular by working the sides of the glass. For example, a wide sapphire sheet can be produced and coloured and then processed, for example with a laser, to obtain smaller timepiece components, such as pallets, wheels, glazings, etc. Preferably, the finalizing step does not alter the chemical composition altered region within the component.

Alternatively, additional processing steps may be carried out in order to finalize the timepiece component, in particular the watch glass, for example simply by forming the bevel or any peripheral portion 4, in particular the bevel portion shown in fig. 1b to 1e, and/or by forming the groove or a single lens or magnifying glass.

As a variant, this step may comprise structuring the features in a coloured transparent member purely for decorative or marking purposes, for example with a laser. Advantageously, therefore, the laser etching carried out on the watch glass does not require adjustment of the parameters, since it acts on the colourless areas of the glass, that is to say outside the chemically altered areas, independently of the colour of the glass obtained according to the invention.

As a variant, this step may consist in forming a configuration of colouring members (structuring). "texturing" may be the formation of raised and/or indented areas on at least one external or internal surface of the coloured component, in order to create distinct reliefs or to vary the thickness of the colouring, so as to form one or more coloured features or features with a colour gradient or colour features of the starting substrate. The configuration may be any hole formed in the surface or thickness of the coloring member, which is not a through hole. Such pores may be micropores or nanopores, preferably of a sufficiently small size to be invisible or substantially invisible to the naked eye. Alternatively, such pores may have a larger macroscopic size, such that they are intentionally visible. In general, the holes may have any cross-section, which is not necessarily circular. The cross-section may be rectangular or star-shaped in nature, for example, or may have any other suitable geometry. Such a configuration can be obtained in particular by any conventional processing technique or by laser processing, in particular by femtosecond laser processing or by Deep Reactive Ion Etching (DRIE) or by chemical etching. It should be noted that the structuring step can be carried out directly on the initial substrate provided in an initial stage of the method, before carrying out the two main steps of the method according to the invention. As a variant, the structuring step can be carried out directly on the coating deposited on the substrate after the first introduction step E1 of the process and before carrying out the second heat treatment step E2 of the process according to the invention.

Additional steps may also include a transparent and colored member obtained by assembly with another component, which may or may not be obtained by the same method. For example, this additional step may consist in assembling the glass with a single lens or magnifying glass, or in assembling the glass, in particular by gluing, with a support having a skirt for assembling the glass on a watch case, or in assembling a plurality of glasses.

Finally, the manufacturing method according to the invention has the following advantages:

the introduction of one or more coloured chemical elements is well controlled in terms of quantity and position, so that it can be calibrated and repeated to obtain the same result required in each implementation;

-also the heat treatment is controlled and repeatable, so as to obtain also in each execution the same coloured transparent member required;

the method is therefore compatible with mass production and horological requirements.

The method is equally applicable to the manufacture of any transparent timepiece component, and transparent timepiece components can be manufactured, the transparent timepiece component includes a substantially planar or curved interior surface, and consists essentially of a transparent material, the transparent material is colored by introducing at least one coloring chemical element through a chemical composition-altering region within the component, this chemical-composition-changing zone extends only in a portion of the total thickness of the timepiece component (that is, not over its entire width), this fraction is on average at most 25% (including 25%) or even at most 2% (including 2%) of the total thickness of the timepiece component, or even at most 0.2% (including 0.2%), and preferably at most 0.07% (including 0.07%), the total thickness of the timepiece component being measured perpendicular to the interior surface of the component or perpendicular to a tangent line formed at the apex of the interior surface of the component. Advantageously, the chemical composition-altering area extends on average over a thickness which is at least 0.0002% of the total thickness of the timepiece component. It should be noted that this thickness of the timepiece component is advantageously substantially the thickness of the starting substrate. As an implementation variant, this thickness of the timepiece component may be reduced with respect to the initial total thickness of the initial substrate, but in such a way as to maintain the above-mentioned range of thicknesses of the chemically altered regions.

The invention is therefore suitable, for example, for the manufacture of watch glasses, single lenses, magnifying glasses, parts of backplates, dials, date plates, timepiece movements jewellery, pallets, wheels.

By the method according to the invention, a timepiece component is obtained with the following advantages:

the coloration is predictable (in terms of shading, especially blue shading, and saturation), repeatable, and distributed in a desired manner: it is uniform over the entire intended surface, which may be very large, for example in the case of sapphire glass, or non-uniform and controlled, for example according to a controlled gradient or predetermined characteristics or inscriptions. It gives the impression of overall coloration despite the thinner areas of chemical composition change. It also gives a visual impression independent of the treated internal or external surface and independent of the overall thickness of the timepiece component.

Ensuring transparency to allow, in the case of watch glasses, reading of the time or indications derived therefrom, viewing of the dial, viewing of the flange of the middle of the case, etc. In addition, this transparency also allows optional charging (excitation) and discharging (emission) of luminescent materials, in particular photoluminescent (phosphorescent and/or fluorescent) materials, which may be present under the glass (on/in the applied characters, needles, pad prints, etc.);

the overall mechanical strength of the initial substrate is maintained at the output of the process: the process does not cause a reduction in mechanical properties;

-at the end of the process, maintaining the surface hardness of the initial substrate on the tinted transparent member;

the appearance of the timepiece component is free of defects, such as accidental uncolored, differently colored or "over-colored" areas, pits, partial milky appearance, through holes, halos. The absence of such defects is achieved on the entire surface of the obtained tinted transparent member, which may be large and may be fully visible to the user, optionally even under backlighting.

The effect can be adjusted by an additional surface inclined at the level of the side of the timepiece component, which may for example have the shape of a bevel;

other geometrical considerations may adjust these effects, such as raised and/or indented structured areas on at least one surface of the timepiece component and/or structured areas within the thickness of the timepiece component.

The invention will now be illustrated by using several series of embodiments examples.

In a first series of examples of implementation, the colorless and transparent single-crystal alumina substrate 10 has a geometry corresponding to the final geometry of the finished watch glass suitable for mounting on a timepiece. This transparent embodiment corresponds to the "reference" embodiment in the table below and in the various examples below.

According to this example, the reference watch glass has a diameter of 29.5mm and a total thickness of 1.8 mm. It has a geometry similar to that shown in fig. 1e, with a chamfer on the periphery of its outer surface inclined at 36 ° at a height f of 0.8mm, and also with grooves and various machining portions at the remaining height of the side 3. Both the outer and inner surfaces thereof are polished.

The starting substrate corresponding to the reference table glass specified above was cleaned in a detergent cleaning bath, then rinsed and dried before being placed in the chamber of a thermal evaporation PVD apparatus. Thus, a cobalt metal coating is deposited on the inner surface of the initial substrate, which corresponds to the first main step of the above-described method. The deposition rate and time are calibrated to give a coating of a specified thickness. The deposit thickness was confirmed by X-ray refraction. This operation was repeated to form a series of coloured elements comprising several different coating thicknesses e' (set values) in the range of 5 to 80nm summarized in the table below. The heat treatment according to the second main step of the process was carried out identically for all the components of the series by holding at a temperature of 1060 ℃ for 2 hours.

A spectrophotometric colorimetric measurement is performed, which is a transmission of the colored member obtained by the method according to the present embodiment, which forms several samples 1.1 to 1.9 at the end of the heat treatment step. The results in the CIELab space are given in the table below. The transmission measurement was carried out by the observer at 2 ° and with a light source D65 between 360nm and 740 nm. The lightness L, the colorimetric values a and b, the saturation C and the hue h (or hue angle) are measured. Transmittance values (T in%) were recorded at 360nm and 460 nm. Y is a transmission coefficient; it takes into account the sensitivity of the eye and the type of illumination: it is determined by the human eye response function (centered on the green part of the visible spectrum) and the "colorimetry technique report" CIE 15: the integral of the spectrally weighted transmission spectrum of light source D65, defined in 2004. These results show in particular that the difference in coating thickness e' directly affects the saturation and hue of the blue color obtained in a manner perceptible to the naked eye. At the end of the introduction step E1, the glass obtained has an increasingly metallic grey appearance and is increasingly opaque as the thickness E' increases. At the end of the heat treatment step E2, the glass had an increasingly saturated blue appearance, while remaining transparent in the cobalt thickness range E' between 5nm and 45 nm. Beyond this thickness, for a given heat treatment, the transparency decreases and therefore the transmittance decreases.

For example, for sample 1.9 (e' ═ 80nm), the transmission was equal to:

55.0% at 460nm, so that the readability through the glass is no longer sufficient, and

38.0% at 360nm, so that the charging of the photoluminescent (phosphorescent and/or fluorescent) material that is transmitted through the glass is no longer sufficient.

In the particular case of this series of examples, it is noted that samples with a thickness e' less than or equal to 12nm have excellent readability. Readability of those samples with a thickness e' less than or equal to 45nm is acceptable. For a thickness e' of 80nm, the sample obscures the reading since the glass is translucent. For a thickness e' of 80nm, reading becomes more difficult due to the reduced transparency of the glass.

The following table gives the results obtained for this series of samples according to the first example:

to illustrate these results, fig. 3a shows the transmittance (T in%) spectra as a function of wavelength (L in nm) for several coating thicknesses according to the series of first examples. Fig. 3b is an enlargement of this fig. 3 a.

In addition, it is noted that when looking at the glass, the coloration looks more intense through the slope of the periphery than through its planar outer surface. In other words, the coloring effect is adjusted by the angle α. The reason for this is the geometry of the components. As mentioned previously and shown in fig. 1b to 1e, this may illustrate the advantage of providing an inclined portion at the level of the outer surface of the glass.

It should be noted that the blue hue observed comes from the formation of cobalt aluminate (possibly CoAl) during the heat treatment at the level of the areas of altered chemical composition of the colored transparent member obtained₂O₄) Cobalt, alumina and oxygen. Fig. 3c is an image of a thin section taken perpendicular to the inner surface of the resulting colored transparent member on the colored transparent member by a Focused Ion Beam (FIB) using a Transmission Electron Microscope (TEM). The inset of the figure represents an electron diffraction image obtained in the treated area close to the inner surface, more specifically at a distance from the surface of less than d. This image makes it possible to confirm the formation of cobalt aluminate and also the thickness d during the colouring phase of the sapphire glass.

The method according to the invention is carried out without reducing the overall mechanical properties of the glass obtained. This result was confirmed on a batch of additional watch glass samples, always taken from the same reference substrate, coated with cobalt layers of various thicknesses by magnetron sputtering, and then heat treated at 1000 ℃ for 3 hours. The breaking strength and hardness of the glass are in no way affected by any presence of the colored chemically altered areas.

In a second series of implementation examples, the colourless, transparent, single-crystal alumina starting substrate 10 used has a geometry corresponding to the final geometry of the finished watch glass (called reference) in the same way as the series according to the first example described above. By varying the heat treatment applied, more specifically by varying the temperature maintained for three hours, a sample of a coloured component is formed. All of these samples were previously coated with a 10nm cobalt metal deposit by thermal evaporation on the interior surface of the substrate.

The following table summarizes the results obtained for these examples:

in addition, according to this series of second examples, fig. 4 shows the transmittance (T, expressed in%) spectra as a function of wavelength (L, in nm) at several holding temperatures (Tp, in ° c).

Of particular note, samples 2.1 to 2.3 have hue angles that increase with holding temperature, and sample 2.1 is green, while samples 2.2 and 2.3 are blue. Above 1400 ℃ (sample 2.4), the sapphire glass becomes colorless and transparent, similar to the untreated sapphire glass (reference sample).

The third series of examples of implementation makes it possible to obtain samples in a similar way to the second series, but with the heat treatment applied simultaneously varying from 30 minutes to 48 hours, keeping the temperature always equal to 900 ℃. All these samples were previously coated with a 5nm cobalt metal deposit on the inner surface of the substrate by thermal evaporation.

The following table summarizes the results obtained for these samples:

sample (I)	t[h]	L*	a*	b*	C*	h*	360nm of T [% ]]	460nm T [% ]]	Y[％]	Perceived color
											Reference to	0	93.5	0.0	0.4	0.4	87.0	82.1	83.6	86.0	Colorless and colorless
3.1	0.5	90.2	-1.6	3.3	3.7	116.3	70.2	74.4	78.3	Grayish green
											3.2	1	92.3	-1.4	0.4	1.5	165.6	77.1	81.1	81.4	Green colour
3.3	3	92.9	-1.0	-1.3	1.6	230.3	81.9	84.5	82.7	Blue color
											3.4	48	93	-1.0	-1.3	1.6	234.6	82.8	84.7	82.8	Blue color

In addition, fig. 5 shows the transmission (T, expressed in%) spectra as a function of wavelength (L, in nm) for several holding times (T, in hours) for a series according to this third example.

Of particular note, as the duration of the heat treatment increases, the coating reacts more effectively with the glass, which results in increased transmission and formation of a blue color. After three hours of heat treatment (example 3.3), the sapphire glass is blue and has sufficient transparency at a wavelength that allows good readability and optional charging and discharging of the photoluminescent material.

In the fourth series of implementation examples, the initial substrate 10 used corresponds always to the reference finished watch glass in the same way as the series according to the first example described above. Examples are carried out by varying the heat treatment applied, more specifically the temperature and/or duration of the applied hold. All these samples were previously implanted with iron, cobalt or titanium by an ion beam ion implantation process (direct implantation of ions in an ion beam).

The following table summarizes the results obtained with these samples:

in addition, fig. 6a to 6c show the transmittance (T, expressed in%) spectra as a function of wavelength (L, in nm) of the samples forming the series of the fourth example.

Of particular note, iron gives an orange color (at 900 ℃ and 1000 ℃), cobalt gives a gray color at 900 ℃, blue color at 1000 ℃, and titanium gives a pale yellow color (at 900 ℃ and 1000 ℃). Treatment at 1600 ℃ gave a clear, colorless glass, whether with iron or cobalt.

The values of hardness and modulus of elasticity obtained by the nano-indentation on the samples forming the series of this fourth example can be concluded as follows: under the test conditions, the mechanical properties (hardness and elasticity) of the sapphire glass are not affected by the coloring process including ion implantation and heat treatment.

In a fifth series of implementation examples, the colourless, transparent, single-crystal alumina starting substrate 10 used has a geometry corresponding to the final geometry of the finished watch glass, called reference watch glass, in the same way as the series according to the first example described above.

The initial substrate corresponding to the reference watch glass was cleaned in a detergent cleaning bath, then rinsed and dried before being placed in the chamber of a thermal evaporation PVD apparatus. Thus, a cobalt metal coating is deposited on the inner 1 or outer surface and bevel 2+4 of the initial substrate. This operation was repeated to form a series of coloured elements comprising several different coating thicknesses e' (set values) of 3, 6 or 9nm, summarized in the table below. For all components of the series, performing recoil injection in the same manner by argon ion bombardment in the same equipment through a plasma immersion method; only the dose of implanted ions (in "atoms/cm" at an energy of 10 kV)²"D for D), this is summarized in the table below. These operations correspond to the first main step of the method described above.

The heat treatment according to the second main step of the process was carried out in the same way for all the members of the series by holding at a temperature of 1000 ℃ for 3 hours.

The following table summarizes the results obtained for these samples:

in addition, fig. 7 shows the transmittance (T, expressed in%) spectrum as a function of wavelength (L, in nm) for several values of the coating thickness e' and the implanted ion dose D according to this fifth example series.

Of particular note, the samples obtained were blue; samples 5.1 to 5.3 and 5.4 to 5.6 have an increasing saturation C with the coating thickness e'. The results were similar using the same treatment parameters, regardless of whether the treated surface (surface 1 or surface 2+4) was used.

The sixth example focuses in particular on the effect on a coloured watch glass (blue in this example), the charging (excitation) and discharging (emission) performance characteristics of a photoluminescent material that may be placed on the dial below the inner surface of the watch glass. A blue glass (sample 6) was prepared according to this embodiment, in which a 9nm cobalt deposit was produced by thermal evaporation on a colorless transparent single crystal alumina substrate 10, followed by a heat treatment comprising holding at 1060 ℃ for 2 hours.

The results of the spectrophotometric measurements of transmission on sample 6 and the reference glass are given in the table below.

Two glasses (reference glass and glass sample 6) are shown in succession on the same table, which includes the markings and the pointers with the application of the commercial photoluminescent material. The luminescence properties of the assemblies with blue glass (sample 6) and reference glass were compared after keeping the table in the dark for 24 hours, followed by standard illumination (using light source D65 for 20 minutes at 400 lux). The decrease in luminescence as a function of time of retention in the dark was measured photometrically [ nCd ]. The relative decrease in the quality of the luminescence properties of the blue glass (sample 6) was evaluated as a percentage of the luminescence intensity of the reference glass.

The relative decrease in the quality of the luminescence properties due to the coloration of sample 6 was 0.8% in 0 to 8 hours and 1.7% in 0 to 22 hours.

Thus, the use of the blue glass according to example 6 has no effect on the quality of the performance of the photoluminescent material tested, compared to a colourless reference glass, as can be seen by the person wearing the watch.

Naturally, the above examples are given in a non-limiting manner in order to illustrate the results obtained by implementing the inventive concept. They can be reproduced with similar effect on any transparent timepiece component other than a watch glass.

The results clearly illustrate the advantages obtained by the process of the invention. On this basis, the person skilled in the art will know how to adjust the deposition thickness e', the material to be used and the heat treatment parameters according to the results desired, in particular in terms of colour and transparency. In particular, it is advantageous to choose to achieve a transmission coefficient (Y) greater than or equal to 68% (including 68%) or even greater than or equal to 79% (including 79%). The substrate may also be chosen such that the average hardness of the outer surface of the timepiece component obtained is greater than or equal to 30GPa and/or greater than or equal to 2016HV0.2, in particular in the case of a watch glass.