EP4051047B1 - Élément décoratif - Google Patents

Élément décoratif Download PDF

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Publication number
EP4051047B1
EP4051047B1 EP20807288.4A EP20807288A EP4051047B1 EP 4051047 B1 EP4051047 B1 EP 4051047B1 EP 20807288 A EP20807288 A EP 20807288A EP 4051047 B1 EP4051047 B1 EP 4051047B1
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EP
European Patent Office
Prior art keywords
microstructure
decorative body
faceted
gemstone
facets
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EP20807288.4A
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German (de)
English (en)
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EP4051047A1 (fr
Inventor
Christian Teissl
Christof NEUHAUSER
Günther Blasbichler
Simone RIESER
Sonja KOPP
Michael Muehlberger
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D Swarovski KG
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D Swarovski KG
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Publication of EP4051047A1 publication Critical patent/EP4051047A1/fr
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    • A—HUMAN NECESSITIES
    • A44—HABERDASHERY; JEWELLERY
    • A44C—PERSONAL ADORNMENTS, e.g. JEWELLERY; COINS
    • A44C17/00—Gems or the like
    • A44C17/001—Faceting gems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B9/00—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor
    • B24B9/02—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground
    • B24B9/06—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain
    • B24B9/16—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of diamonds; of jewels or the like; Diamond grinders' dops; Dop holders or tongs
    • B24B9/163—Machines or devices designed for grinding edges or bevels on work or for removing burrs; Accessories therefor characterised by a special design with respect to properties of materials specific to articles to be ground of non-metallic inorganic material, e.g. stone, ceramics, porcelain of diamonds; of jewels or the like; Diamond grinders' dops; Dop holders or tongs of gem stones or convex surfaces, cabochons

Definitions

  • the invention relates to a decorative element, and in particular to a decorative element comprising a faceted body with a flat back surface and a concavo-convex microstructure provided on the flat back surface of the faceted body.
  • Articles comprising the decorative element and methods of making the decorative element are also provided.
  • Faceted decorative components such as gemstones and crystals have been used to embellish products for a long time.
  • Conventional gemstones are usually grinded and polished by means of grinding wheels or rollers to obtain a convex outer shape comprising multiple sets of facets.
  • the optical properties of gemstones are particularly important characteristics in this context, and these properties are defined at least in part by the geometry of the gemstone.
  • the optical properties of a gemstone are often compared to those of a gemstone with a brilliant cut.
  • the brilliant cut is a complex geometry with four different types of crown facets (including a table) and two different types of pavilion facets, all of which interact to create advantageous optical properties such as brilliance.
  • Such components can be combined with a mirrored surface on the flat back in order to create a 'sparkling effect' where light incident on the mirror surface is reflected in multiple directions due to the interaction with the crown facets of the component.
  • flat backed gemstones typically have inferior optical properties compared to e.g. a brilliant cut, due to the absence of pavilion facets, even in the presence of a reflective layer.
  • EP 3 141 142 A1 - in the name of SWAROVSKI D KG - refers, in paragraph [0001] thereof, to "a decorative jewellery element which contains a transparent jewellery stone, a wavelength-selective layer and a bearing surface whose colour can be changed' (according to a machine translation thereof).
  • the invention provides a decorative element comprising: a faceted decorative body with a flat back surface, a microstructure on the flat back surface of the decorative body, wherein the microstructure comprises a faceted region, and an at least partially reflective layer on at least a portion of the faceted region of the microstructure; wherein the combination of the faceted region and the at least partially reflective layer is configured to reflect light incident on the at least partially reflective layer through the decorative body and/or the microstructure.
  • the microstructure is configured to reflect light in multiple directions back through the microstructure and/or the decorative body.
  • light is reflected in a manner similar to that of a decorative body comprising a faceted pavilion rather than a flat back.
  • the microstructure reflects light that passes through the decorative body at angles dictated by the refractive index of the microstructure and the angles of the faceted region, giving the appearance of a multifaceted decorative body, such as a decorative body comprising a pavilion having pavilion facets.
  • a faceted decorative body having a 'flat back' requires that the back side of the decorative body has at least a region that is substantially flat and aligned parallel to a girdle plane and/or table of the decorative body.
  • a flat back implies that at least about 25%, at least about 33%, at least about 50%, at least about 66%, at least about 75%, at least about 80%, or at least about 85% of the surface area of the backside of the decorative body is flat and contiguous (and arranged parallel with the girdle plane / table of the decorative body).
  • the microstructure has a height of less than about 1,000 ⁇ m, less than about 500 ⁇ m, less than about 300 ⁇ m, less than about 200 ⁇ m; and/or at least about 10 ⁇ m, at least about 20 ⁇ m, at least about 30 ⁇ m, at least about 40 ⁇ m or at least about 50 ⁇ m or at least about 100 ⁇ m.
  • the faceted region may be created by concave faceted portions of the microstructure.
  • the concave faceted portions of the microstructure have a depth of between about 1 ⁇ m and about 1,000 ⁇ m, between about 5 ⁇ m and about 500 ⁇ m, between about 10 ⁇ m and about 400 ⁇ m, between about 20 ⁇ m and about 300 ⁇ m, between about 30 ⁇ m and about 200 ⁇ m, or between about 40 ⁇ m and about 100 ⁇ m.
  • the combination of the depth and the angle of the facets relative to the flat-back surface determine the size, appearance and light reflecting effect of the faceted portion of the microstructure. Beneficially the facets are visible to the naked eye of the observer.
  • the facets in the faceted region are each inclined relative to the flat back surface of the faceted decorative body by an angle between about 1° and about 30°, between about 2° and about 25°, between about 3° and about 20°, or between about 4° and about 16°.
  • each of the facets is inclined relative to the flat back surface of the faceted decorative body by substantially the same angle as the other facets of the microstructure.
  • the angles between the facets in the faceted region and the flat back surface of the faceted decorative body are selected from one of two different angles.
  • the facets are selected from one of three or one of four different angles. Where facets at more than one angle are used, the number of facets at each different angle is suitably the same.
  • the facets are arranged symmetrically on the microstructure.
  • the facets of the microstructure may advantageously be defined by forming one or more pyramid profile within the microstructure, wherein each of the sides of the pyramid defines a facet of the faceted region of the microstructure.
  • the sides of the pyramid are suitably planar.
  • the sides of the pyramid may be angled relative to the plane of the surface on which the microstructure is provided by an angle defined above.
  • the facets defined by the pyramid are arranged at angles of between 5° and about 12°, such as about 6°, 7°, 8°, 9°, 10 or 11°.
  • each facet of a pyramid is arranged at the same angle relative to the plane of the surface on which the microstructure is provided.
  • a particularly preferred pyramid structure as facet angles of between about 10° and about 12°; for example, about 11°, such as about 11.2°.
  • the pyramid may have any appropriate number (x) of planar sides, for example, x may be an integer between 4 and 13; beneficially between 5 and 12; preferably between 6 and 11, such as 6, 7, 8, 9, 10 or 11.
  • x may be an integer between 4 and 13; beneficially between 5 and 12; preferably between 6 and 11, such as 6, 7, 8, 9, 10 or 11.
  • the facets / sides of the pyramid are equal size, e.g. for a 9-sided pyramid the sides are oriented at angles of 40° rotation relative to each adjacent side.
  • all sides / facets of the pyramid are not equally sized.
  • a pyramid may include two or three different sizes of facet.
  • the pyramid has rotational symmetry.
  • the microstructure includes a single pyramid of facets.
  • the largest outer perimeter (i.e. the hypothetical base) of the pyramid may be substantially the same size as the surface of the microstructure.
  • the pyramid it may be preferable that the pyramid is smaller than the surface of the microstructure.
  • the pyramid it may be convenient to consider the pyramid to have a radius (Pr), wherein the radius (Pr) defines a circle having a circumference that intersects the vertices of the base of the pyramid.
  • the radius defining the size of the pyramid may suitably be between about 20% and about 80% of the radius R of the largest circle that fits within the dimensions of the flat back.
  • the pyramid has a radius (Pr) between about 30% and about 75% of the radius R, and more preferably between about 40% and about 66% of the radius R.
  • Pr may be about 60%, about 62%, about 64%, about 66%, about 68% or about 70% of the radius R.
  • the pyramid has 7 walls (facets), the angle of the facets is approximately 11° (e.g. 11.2°), and the pyramid has a radius Pr that is approximately 64% (e.g. 63.8%) of the radius of the flat back surface.
  • the remainder of the microstructure may be planar, e.g. flat and on a plane parallel to the surface of the decorative body on which the microstructure is provided.
  • the facets of the microstructure may advantageously be formed by a plurality of grooves, wherein the walls of the grooves create the facets in the microstructure.
  • the grooves comprise two planar walls that are angled relative to the flat back surface of the decorative body at angles of ⁇ and ⁇ , respectively.
  • ⁇ and ⁇ may be the same for all of the grooves in the plurality of grooves.
  • ⁇ and ⁇ may be the same, whereas in other embodiments ⁇ and ⁇ may be different.
  • the angle between each of the planar walls of the grooves and the flat back surface of the decorative body is individually selected from between about 1° and about 30°, between about 2° and about 25°, between about 3° and about 20°, or between about 4° and about 16°.
  • the grooves have a V-shape.
  • the grooves may have a polygonal profile that is not strictly a V-shape.
  • each side wall of a groove may have two or more planar surfaces arranged at different angles relative to the flat base of the decorative body on which the microstructure is provided.
  • the base of the groove may be formed with a flat region rather than a sharp vertex.
  • the pattern of facets in the microstructure, or the pattern of grooves defining the facets in the microstructure may be symmetrical.
  • the degree of symmetry of the facets / grooves of the microstructure may be the same or different to the degree of symmetry of the decorative body (where the decorative body has a defined symmetry).
  • each grooves of the plurality of grooves is offset from each adjacent groove by an angle of rotation relative to a centre point or approximate centre point of the microstructure or decorative body (e.g. where the microstructure and/or the decorative body is not substantially circular).
  • the grooves are rotated relative to each other by a constant angle about a(n approximate) centre point of the decorative body, and are located relative to each other to form an n-fold rotational symmetrical pattern.
  • the angle of offset between each groove is selected to be 360°/n.
  • the faceted region of the microstructure may comprise a pattern of facets that has n-fold rotational symmetry.
  • n is an integer between 4 and 13; beneficially between 5 and 12; preferably between 6 and 11, such as 6, 7, 8, 9, 10 or 11.
  • the decorative body is a flat back gemstone having a substantially circular girdle.
  • the faceted region of the microstructure beneficially is formed of 6, 7, 8 or 9 grooves equally spaced and oriented along tangents to an imaginary circle having a radius L R of between 50% and 75% of the radius R of the largest circle that fits within the dimensions of the flat back surface.
  • the facets of the faceted portion are defined by 6 linear grooves arranged respectively at 60° rotations about the imaginary circle relative to each adjacent groove, and at a radius L R between about 64% and 66% of the radius R, or between about 87% and 89% of the radius R.
  • the angle of inclination of each of the walls is between about 4° and about 16°, more suitably between about 5° and about 10°, such as about 5°, about 6°, about 7° or about 8°.
  • the angle of one wall of each groove ( ⁇ ) is different to the angle of the other wall of each groove ( ⁇ ).
  • the angle ⁇ may be about 4.9°, 5.3° or 5.4° and the angle ⁇ may be about 7.9°, 8.2° or 14.6°.
  • the wall of the groove having an angle ⁇ may be arranged towards the centre of the circle that defines the tangent on which the groove is aligned; whereas in some other preferred embodiments, the wall of the alignment of the grooves alternates such that a first groove is oriented such that the wall having an angle ⁇ is positioned towards the centre of the circle, and each adjacent groove is oriented such that the wall having an angle ⁇ is positioned towards the centre of the circle.
  • each of the plurality of grooves has two planar walls that are angled relative to the flat back surface of the decorative body at angles of ⁇ and ⁇ , respectively.
  • ⁇ and ⁇ may be the same for all of the grooves in the plurality of grooves.
  • ⁇ and ⁇ may be the same, whereas in other embodiments ⁇ and ⁇ may be different.
  • the microstructure may be formed integrally with the decorative body.
  • the microstructure may be formed by imprinting the flat back surface of the faceted decorative body.
  • the imprinting is conveniently by imprint lithography, for example, nanoimprint lithography (NIL).
  • NIL nanoimprint lithography
  • the microstructure and decorative element may be formed as a single unit, for example, by sol-gel manufacturing processes, additive manufacturing / 3D printing, or injection molding. This can have the benefit of convenient manufacture and/or enabling the refractive index of the decorative body and microstructure to be exactly matched.
  • the microstructure is made from a material obtained by curing a UV curable resin composition.
  • the microstructure is formed of a material that has a refractive index that is similar to, such as within 30%, within 20%, within 10% or within 5% of that of the material of the decorative body.
  • a refractive index that is similar to, such as within 30%, within 20%, within 10% or within 5% of that of the material of the decorative body.
  • the microstructure is formed of a transparent material.
  • the decorative body is preferably formed of a transparent material.
  • the faceted decorative body is a gemstone.
  • the gemstone may be made of glass, crystal glass, glass ceramic, plastic or cubic zirconium.
  • the decorative body may be of any suitable size and shape; for example, the decorative body may be circular, oval, rectangular or square. In some embodiments the decorative body may be multi-sided and approximating towards a circle, oval, rectangle or square.
  • the lateral dimensions of a decorative body according to the invention may range from between about 1 mm and about 250 mm. For example, between about 1 mm and about 150 mm, between about 2 mm and about 120 mm, between about 2 mm and about 100 mm, between about 3 mm and about 80 mm or between about 3 mm and about 60 mm, When the decorative body is circular, the decorative body may beneficially have a diameter in the above ranges.
  • the term 'diameter' may refer to the diameter of the largest circle that would fit within the geometry of the decorative body.
  • the height of the decorative body may be approximately the same as the diameter of the gemstone; for example, within 25%, within 20%, within 15% or within 10% of the diameter of the gemstone.
  • the decorative body has a height between about 1 mm and about 120 mm, between about 1 mm and about 100 mm, between about 2 mm and about 80 mm, or between about 2 mm and about 60 mm.
  • the decorative element of any preceding claim further comprising one or more protective layers on the at least partially reflective layer; and/or optionally further comprising an adhesive layer on the protective layer.
  • the invention provides a decorative element comprising: a decorative body comprising a front surface and a flat back surface, a microstructure on the flat back surface of the decorative body, wherein the microstructure comprises a faceted region, and an at least partially reflective layer on at least a portion of the faceted region of the microstructure; wherein the combination of the faceted region and the at least partially reflective layer is configured to reflect light incident on the at least partially reflective layer through the decorative body and/or the microstructure.
  • the decorative body may be a sheet material, such as a glass or plastics (polymeric) sheet material (e.g. a window or partition, such as a room divider or door).
  • the front surface may be rounded (e.g. convex), but not faceted.
  • the decorative body may be a cabochon shape.
  • the decorative body is transparent.
  • the invention provides a decorative element comprising: a decorative body comprising a front surface and a back surface, a microstructure on the back surface of the decorative body, wherein the microstructure comprises a faceted region, and an at least partially reflective layer on at least a portion of the faceted region of the microstructure; wherein the combination of the faceted region and the at least partially reflective layer is configured to reflect light incident on the at least partially reflective layer through the decorative body and/or the microstructure.
  • the front surface of the decorative body is beneficially a faceted surface, such as present in a gemstone.
  • the back surface of the decorative body on which the microstructure is provided is planar, i.e. it defines a contiguous flat or level surface arranged at a constant relative gradient.
  • the back surface may be the surface of a 'flat back' decorative body / gemstone as defined in the first aspect of the invention.
  • the back surface of the decorative body on which the microstructure is provided may be an inclined surface or 'facet' located on the opposite side of the decorative body to the front surface (e.g. the planar back surface may be a pavilion facet).
  • the back surface may be inclined relative to (i.e. not parallel with) the girdle plane.
  • any angle of inclination may be selected according to the shape and structure of the decorative body.
  • the angle of inclination may be between about 1° and about 80°, between about 2° and about 70°, between about 3° and about 60°, between about 4° and about 50° degrees.
  • the angle of inclination may be between about 5° and about 45°, between about 10° and about 40°, or between about 20° and about 30°.
  • the angle of inclination of the planar back surface may be measured relative to a 'table' of the decorative body. Where the decorative body does not have a classic 'table', e.g.
  • the 'table' may be considered to represent the largest planar surface on the front surface of the decorative body, and/or the girdle may be considered to represent the line / region around the decorative body at which the decorative body has its largest transverse cross-sectional area.
  • the facets of the faceted region of the microstructure suitably have a maximum facet dimension that is at least about 5 times smaller than a maximum dimension of the surface on which the microstructure is provided.
  • the maximum facet dimension is at least about 10 times, at least about 15 times, at least about 20 times, at least about 25 times, at least about 50 times, or at least about 100 times smaller than a maximum dimension of the surface on which the microstructure is provided.
  • the facets of the microstructure have a surface area that is at least about 10 times, at least about 25 times, at least about 50 times, at least about 100 times, at least about 250 times, or at least about 500 times smaller than the surface area of the surface on which the microstructure is provided.
  • the faceted portion of the microstructure is able to increase the proportion and/or distribution of light that is reflected from the respective back surface of the decorative body in comparison to the decorative body in the absence of the microstructure.
  • the facets of the microstructure are beneficially not so small that the reflected light to overly dispersed / fragmented.
  • the facets are a size that creates facet reflections that are visible with the naked eye of the observer.
  • a method of making a decorative element comprising: providing a faceted decorative body having a flat back surface; forming a microstructure on the flat back surface of the decorative body, wherein the microstructure comprises a faceted region; forming an at least partially reflective layer on at least a part of the faceted region of the microstructure, wherein the combination of the faceted region of the microstructure and the at least partially reflective layer is configured to reflect light incident on the at least partially reflective layer through the decorative body and/or the microstructure.
  • a method of making a decorative element comprising: providing a decorative body having a flat back surface; forming a microstructure on the flat back surface of the decorative body, wherein the microstructure comprises a faceted region; forming an at least partially reflective layer on at least a part of the faceted region of the microstructure, wherein the combination of the faceted region of the microstructure and the at least partially reflective layer is configured to reflect light incident on the at least partially reflective layer through the decorative body and/or the microstructure.
  • the decorative body may be a sheet material, such as a glass or plastics (polymeric) sheet material (e.g. a window or partition, such as a room divider or door).
  • the front surface may be rounded (e.g. convex), but not faceted.
  • the decorative body may be a cabochon shape.
  • a method of making a decorative element comprising: providing a decorative body comprising a front surface and a back surface; forming a microstructure on the back surface of the decorative body, wherein the microstructure comprises a faceted region; forming an at least partially reflective layer on at least a part of the faceted region of the microstructure, wherein the combination of the faceted region of the microstructure and the at least partially reflective layer is configured to reflect light incident on the at least partially reflective layer through the decorative body and/or the microstructure.
  • the steps of providing a decorative body comprising a front surface and a back surface and forming a microstructure on the back surface of the decorative body, wherein the microstructure comprises a faceted region comprises forming the microstructure and faceted region integrally with the decorative body, for example using a sol-gel manufacturing process, by additive manufacturing (e.g. 3D-printing) or by injection molding.
  • the method of the fourth, fifth and/or sixth aspects of the invention may further comprise providing a working stamp for use in the method by replicating a master stamp into a polymeric stamp material.
  • the master stamp may be a metallic master stamp, a hard metal master stamp or a non-metallic master stamp.
  • the master stamp and/or the working stamp has a low surface roughness and/or a high flatness.
  • the flatness and roughness parameters match those specified in relation to other aspects and embodiments of the invention described herein.
  • creating a plurality of facets in a metal or non-metallic substrate comprises creating a plurality of facets defining a pyramid in the substrate.
  • the faceted region formed in the microstructure comprises a plurality of facets defining a pyramid shaped profile.
  • the pyramid in the microstructure is a concave pyramid in which the apex points towards the decorative element.
  • providing a faceted decorative body may comprise providing a plurality of faceted decorative bodies and positioning the decorative bodies on a carrier by sieving the decorative bodies.
  • the methods of the invention may further comprise transferring the sieved decorative bodies onto a centring plate, and then transferring the decorative bodies onto the carrier.
  • aspects and embodiments of the fourth, fifth and sixth aspects of the invention may comprise any or all of the features of the first, second and third aspects.
  • any of the features of the decorative body, microstructure and any coatings or layers applied thereon and described in relation to the first, second and third aspects apply equally to the decorative body, microstructure and any coatings or layers applied thereon of the fourth, fifth and sixth aspects.
  • the invention provides an article comprising a decorative element according to any aspect or embodiment of the invention.
  • the article is a decorative article.
  • Embodiments of this aspect may comprise a decorative element having any of the features of the decorative element of the first to sixth aspects.
  • any of the aspects of the invention may comprise any of the features described in relation to any other aspect of the invention, unless such features are clearly not compatible.
  • any of the features of any embodiment of the invention are (where not obviously incompatible), intended and envisaged to be combined in any and all combinations; and all such combinations are hereby encompassed.
  • any one or more optional feature of the decorative body are intended to be combined with any one or more optional features of the microstructure and any one or more optional features resulting from the methods described; and any such resulting decorative element is considered to represent a decorative element according to the invention, which is solely defined by the appended claims.
  • a decorative element with superior optical properties could be obtained by combining a faceted decorative body with a flat back surface (i.e. a flat back gemstone or crystal) with a concavo-convex microstructure on the flat back surface of the decorative body.
  • the terms 'back' / 'bottom', and 'front' / 'top' surface are used to refer to the surfaces of a decorative element / faceted transparent body / gemstone that when incorporated in an article (such as e.g. when applied to the surface of an article), are intended to face towards a viewer (front / top surface), or away from a viewer, such as towards the surface on which the decorative element / faceted transparent body / gemstone is applied or supported (back / bottom surface), respectively.
  • decorative elements / faceted transparent bodies / gemstones may have a complex geometry, as required by the circumstances, and as such a back or front surface may, in fact, comprise a collection of jointed or disjointed surfaces.
  • a front surface is intended to be visible in use, whereas a back surface is intended to be attached to or otherwise combined with an article.
  • FIGs 1A, 1B and 1C show schematic top ( Figure 1A ), bottom ( Figure 1B ) and side ( Figure 1C ) views of a brilliant cut gemstone 1 as known in the art.
  • the gemstone 1 comprises a crown 2, a pavilion 6, and a girdle 4.
  • the crown 2 forms the top (or 'front') part of the gemstone 1.
  • the crown comprises a large flat facet 12 called the 'table' which is parallel to the plane of the girdle 4, and three types of crown facets 8, 10, 14 provided between the table 12 and the girdle 4.
  • Facets 8 are commonly referred to as 'bezel facets'.
  • Facets 10 are commonly referred to as 'star facets'.
  • Facets 14 are commonly referred to as 'upper half facets'.
  • the gemstone illustrated on Figures 1A to 1C has an eight-fold symmetry in both the crown 2 and the pavilion 6.
  • the crown comprises an octagonal table 12, eight star facets 10, eight bezel facets 8, and sixteen upper half facets 14. Pairs of upper half facets 14 alternate with single bezel facets 8 around the upper perimeter of the girdle 4.
  • the pavilion 6 forms the bottom (or ⁇ back' or 'lower') part of the gemstone 1.
  • the pavilion 6 comprises two types of facets.
  • a first set of pavilion facets 16 is commonly referred to as 'pavilion main facets' and meet at an apex 20.
  • the apex 20 may be an apex in the strict geometric sense of the word, or may be in the form of a small flat facet referred to as a 'culet'.
  • the culet when present, is typically significantly smaller than the other pavilion facets.
  • a second set of pavilion facets 18 is commonly referred to as ⁇ lower half facets'.
  • the pavilion 6 comprises eight pavilion main facets 16 and sixteen lower half facets 18. Pairs of lower half facets 18 alternate with single pavilion main facets 16 around the lower perimeter of the girdle 4.
  • the girdle 4 is the region that forms the junction between the crown 2, and the pavilion 6, if present. As such, the girdle 4 is the region at which the gemstone has its largest transverse dimension.
  • the girdle is associated with an imaginary plane P G , referred to as the 'plane of the girdle' or 'girdle plane', illustrated by the dashed line on Figure 1C .
  • the plane P G is arranged such that all of the crown facets (and all of the pavilion facets, if present) within a set of facets have essentially the same orientation and distance to the plane P G , when taking into account symmetries in the set.
  • the upper half facets 14 are provided in pairs where each pair comprises facets that mirror each other.
  • a ⁇ set' or ⁇ type' of facets refers to a group of facets that are substantially identical in shape, and that have the same or symmetrical orientations relative to the girdle plane P G . Further, the plane P G is arranged such that it is parallel to the table 12.
  • the light return is the extent of internal and external reflections of 'white' light seen in a polished gemstone when viewed face-up.
  • the scintillation is the appearance of spots of light seen in a polished gemstone when viewed face-up that flash as the gemstone, observer, or light source moves (also referred to as ⁇ sparkle') and the relative size, arrangement, and contrast of bright and dark areas seen in a polished gemstone when viewed face-up while that gemstone is still or moving (also referred to as 'pattern'). Scintillation can be quantified using an apparatus and set up defined by the American Gemological Society in J. Sasian et al.
  • the system for measuring parameters of a gemstone as illustrated in Figure 2 comprises using a light source around a hemisphere H centred on the gemstone 1 and extending from the girdle plane P G of the gemstone 1 under evaluation, and evaluating the influence of light coming from different angles along the hemisphere H on light reflections seen by an observer O looking at the gemstone from the front / top (i.e. perpendicular to the girdle plane P G , through the table 12 of the gemstone if present).
  • the hemisphere H is divided into three distinct segments 22, 24, 26, and the light reflections caused by illumination of these segments are separately evaluated.
  • the hemisphere H is divided into a segment 26 of shallow-angle light, a segment 24 of intermediate angle light, and a segment of steep angle light 22.
  • An ideal brilliant cut should also preferably have a high fraction of intermediate-angle light areas (shown as dark areas in the pattern 24'), and a small fraction of shallow-angle light areas (shown as dark areas in the pattern 26').
  • a gemstone with such properties such as e.g. the brilliant cut of Figures 1A to 1C can have light return and fire values of about 69% and 50%, respectively, for light return and fire, for an Ideal Cut (Tolkowsky) diamond, where light return and fire may be measured according to the Gemological Institute of America (GIA) standard as set out in Moses et al., 2004 (Gems & Gemology, Fall 2004, Vol. 40, No. 3, https://www.gia.edu/gemsgemology/fall-2004-grading-cut-quality-brilliant-diamond-moses ), as implemented in WO 2015/027252 A1 .
  • GAA Gemological Institute of America
  • fire can be quantified as a percentage of the maximum possible fire (all white light incident on the gemstone is reflected onto a measurement area and the colour saturation of this reflected light is complete), and the light return can be quantified as a percentage compared to the light return that would be obtained from a sample of Spectralon ® of the same size as the gemstone under evaluation.
  • the decorative element 400′′′ further comprise a layer of pre-applied adhesive 260.
  • pre-applied adhesive may enable easy application of the finished decorative element to the surface of an article.
  • the features of the layer of pre-applied adhesive 260 and/or protective layer 250 may be combined with any geometries of the microstructure, including, in particular, geometries where the second major surface comprises a continuous pattern of facets that extends substantially over the whole area of the second major surface 220, and geometries where the second major surface 220 comprises a first faceted region 220A and a second, substantially flat region 220B.
  • the adhesive may be a non-reactive thermal adhesive, also known as hot-melt adhesive.
  • a pre-applied hot-melt adhesive may enable easy application of the gemstone to many surfaces including e.g. garments and textiles, etc.
  • the layer of adhesive may have a thickness between about 50 ⁇ m and about 400 ⁇ m, such as between about 100 ⁇ m and about 200 ⁇ m.
  • layers of hot melt adhesive in the above ranges may provide for sufficient adhesion even on porous substrates such as textiles.
  • the layer of hot melt adhesive is too thick, the risk of the hot melt adhesive spilling out when the decorative element is applied to a surface increases, resulting in possible application problems, loss of aesthetic quality, and waste of adhesive.
  • the optimal amount of hot-melt adhesive to be applied may depend on the particular geometry of the microstructure.
  • the hot melt glue is a copolyamide-based glue, such as Griltex ® 1A from EMS-CHEMIE.
  • the hot melt glue is a thermoplastic polyurethane-based glue, such as VP 1006 by Collano ® AG.
  • the refractive index of the material of the gemstone / faceted body may be at least about 1.45.
  • the material of the gemstone has a refractive index of at least about 1.5 and not more than about 1.8, such as between about 1.55 and about 1.7.
  • Physical properties such as the refractive index influence the path of the light through a gemstone. As such, refractive indices within these ranges may further increase the brilliance of the gemstone.
  • the faceted body / gemstone is made of a transparent material.
  • the term 'transparent' is used throughout this disclosure to refer to a material that has a transparency higher than zero.
  • a material is called transparent if it allows the transport of light, suitably at least visible light.
  • the material is transparent in the conventional sense, i.e. allowing (at least visible) light to pass through the material without being scattered.
  • the gemstone can be made of a wide variety of materials.
  • the gemstone may be made of glass, plastic or cubic zirconium.
  • the gemstone is made of crystal glass.
  • Transparent bodies made of glass or plastic are preferred, because they are low cost, non-conductive and are most readily provided with facets.
  • Gemstones made of glass, and in particular crystal glass are particularly preferred, for their superior optical properties.
  • the invention is not limited in principle with respect to the composition of the glass.
  • 'Glass' in this context means any frozen supercooled liquid that forms an amorphous solid.
  • Oxidic glasses, chalcogenide glasses, metallic glasses or non-metallic glasses can be employed.
  • Oxynitride glasses may also be suitable.
  • the glasses may be one-component (e.g. quartz glass) or two-component (e.g. alkali borate glass) or multi-component (e.g. soda lime glass) glasses.
  • the glass can be prepared by melting, by sol-gel processes, by shock waves or by any other appropriate means. Such methods are known to the skilled person.
  • Inorganic glasses, especially oxidic glasses, are preferred. These include silicate glasses, soda lime glasses, borate glasses or phosphate glasses. Lead-free crystal glasses are particularly preferred.
  • the gemstone is made of soda lime glass.
  • the faceted transparent body may alternatively be made of lead and barium-free crystal glass. Examples of suitable lead and barium-free crystal glass compositions for use in accordance with the present invention are disclosed in e.g. EP 1725502 and EP 265' 49 .
  • plastics can be employed as another raw material for the preparation of the gemstone.
  • Transparent plastics are preferred.
  • acrylic glass polymethyl methacrylates, PMMA
  • PC polycarbonate
  • PVC polyvinyl chloride
  • PS polystyrene
  • PPO polyphenylene ether
  • PE polyethylene
  • PMMI poly-N-methylmethacrylimide
  • a preferred plastic is poly-N-methylmethacrylimide, which is sold, for example, by Evonik under the name Pleximid ® TT70.
  • Pleximid ® TT70 has a refractive index of 1.54, and a transmittance of 91% as measured according to ISO 13468-2 using D65 standard light.
  • the gemstone is coloured.
  • the colouring may be provided as a colouring agent throughout the material of the gemstone.
  • a colouring may be provided as a coating or surface treatment on at least a region of a surface of the gemstone.
  • a coating or surface treatment may be provided on at least a region of the crown facets and/or at least a region of a substantially flat back surface of the gemstone.
  • Colouring and decorative coatings may enable the gemstone to be provided with a variety of decorative effects, improving their flexibility of use. Such colourings and decorative coatings are preferably configured so that the gemstone remains transparent to light entering through the crown facets.
  • the largest transverse dimension of the gemstone (also referred to herein as its diameter) may be between about 1 and 250 mm, between 1 and about 150 mm or between 1 and about 100 mm.
  • the transverse dimension may be between about 1 and 80 mm, between 1 and 60 mm, between 1 and 40 mm, between 1 and 20 mm, or between 2 and 12 mm.
  • the girdle may be substantially circular. In embodiments where the girdle is not substantially circular, the term 'diameter' may refer to the diameter of the smallest circle that would fit the geometry of the girdle.
  • the microstructure 200 may be formed from a polymeric material, which is suitably obtained by curing a resin or lacquer.
  • the microstructure 200 may be obtained by shaping and curing a curable resin or lacquer to obtain a solid microstructure.
  • the microstructure is made from a transparent material.
  • the use of a transparent material enables visible light to travel through the material of the microstructure such that it can be at least partially reflected by the at least partially reflective layer, where the combination of faceting and reflection results in an improvement in the optical properties of the decorative element compared to a flat back gemstone with a reflective layer.
  • the microstructure may be made from any polymer that is suitable for imprinting, as known in the art.
  • the microstructure is made from hybrid polymers.
  • hybrid polymers commercialised under the name OrmoClear ® from micro-resist technology GmbH may be suitable.
  • the microstructure is made from UV-curable or thermally curable resins / lacquers.
  • the microstructure may be made from a thermosetting material, such as e.g. sol-gel or polycarbonate.
  • the microstructure may be made from a material obtained by curing a curable resin composition, for example, a UV curable resin composition. This may enable the microstructure to be provided by forming a resin composition in a plastic state then curing it to obtain a substantially solid structure.
  • the microstructure is beneficially made from a material that has a refractive index that is similar to that of the material of the gemstone / faceted body.
  • the microstructure may be made from a material that has a refractive index between about 1.4 and about 2.42, and beneficially between about 1.52 and about 2.18.
  • the microstructure may be made by curing a resin / lacquer that, when cured, has a refractive index within the above ranges and, preferably, that is similar to that of the material of the gemstone / faceted body.
  • the material of the microstructure is chosen to be compatible with the material of the gemstone / faceted body and/or with the material of the at least partially reflective layer.
  • the materials may be considered to be compatible if they show good levels of adhesion and/or do not adversely react with each other. The skilled person is able to determine whether such materials are compatible using his / her common general knowledge and/or by routine experimentation.
  • the microstructure is made by curing a resin / lacquer that, in the uncured state, has a viscosity that is sufficient to remain on the surface on which it is applied during imprinting, but not so high as to be difficult to apply.
  • the curable resin / lacquer composition has a viscosity below about 3.5 Pas or below about 3.3 Pas: for example, between about 0.5 and about 3.5 Pas, between about 1.0 and about 3.4 Pas, between about 1.5 and about 3.3 Pas; and suitably between about 2.0 and about 3.2, or between about 2.6 and about 3.2 Pas.
  • a preferred composition has a viscosity of around 2.9 Pas.
  • curable compositions with a pre-cured viscosity in the above ranges may be conveniently applied as thin uniform coating films.
  • a suitable resin composition may have a pre-cured viscosity such that the compositions can be applied in layers of the thickness described above in relation to layer 200; for example, between about 1 ⁇ m and about 300 ⁇ m. This may be particularly advantageous for use in nanoimprint lithography.
  • the microstructure is made by curing a resin / lacquer that exhibits low shrinkage during curing.
  • a resin / lacquer composition may be considered to have low shrinkage if the volumetric shrinkage during curing (i.e. difference in volume between the uncured composition and the cured composition) is below about 10%, below 7%, below 5% or below 2%.
  • the facets 230 of the microstructure 200 are each inclined relative to the plane of the flat back surface 150 of the gemstone by a characteristic angle ⁇ , ⁇ .
  • all of the facets 230 of the microstructure are inclined by the same characteristic angle, or are adjacent to facets that are inclined by the same characteristic angle, as shown on Figure 5B .
  • the microstructure comprise a first group of facets 230a inclined relative to the surface 150 by a first angle ⁇ , which are adjacent to a second group of facets 230b inclined relative to the surface 150 by a second angle ⁇ , where ⁇ and ⁇ are different, as shown on Figure 5C .
  • the relatively simple pattern of grooves shown on Figure 6C can be used to generate a microstructure with a complex pattern of facets that has the ability to, when combined with an at least partially reflective layer, reflect light back through the gemstone in multiple directions in a gem-like manner.
  • the grooves are arranged to generate a pattern that has high light return, fire and scintillation as explained above, in a similar way to that of gemstone cuts.
  • a master stamp for imprinting is provided.
  • a master stamp is typically a metallic structure that can be used to replicate a pattern onto a working stamp.
  • a nickel or nickel phosphorus stamp may be used.
  • the step of providing a metallic master stamp may comprise creating a plurality of facets in a metal substrate using a monocrystalline diamond cutting tool.
  • the plurality of facets may be created by forming a plurality of grooves, as explained above.
  • the plurality of facets may be created by forming a pyramid shape (or reverse groove) as shown on Figure 4B and Figure 22C , using a monocrystalline diamond cutting tool.
  • the one or more working stamps are typically provided on a support, such as, for example, an imprinting roller.
  • the working stamps may be fixed directly on a solid support (e.g. a metallic roller) or may be separated from the solid support by one or more flexible layers.
  • the use of flexible layers between the wording stamp and solid support may help to increase the tolerance of the process to sight difference in distances between the working stamp and the material to be imprinted (for example due to slight differences in the height of the gemstones on which the microstructure is provided).
  • Suitable materials for use as the one or more flexible layers are known to the skilled person.
  • a soft PVC material may be used.
  • a soft PVC layer may have a thickness of approx. 2 to 3.5 mm, for example, about 2.7 mm. Subsequent process parameters can be adapted to the hardness of the flexible layers, as would be known to the person of skill in the art.
  • the sieved gemstones may then optionally be centred 730b by transferring the gemstones from a sieving plate to a centricity plate.
  • a centricity plate may for example comprise a plurality of rubber rings in which the gemstones are centred in the x-y direction. Transfer to a centricity plate may further increase the positional accuracy compared to sieving alone.
  • the gemstones are positioned with a precision (tolerance) below about 0.1 mm.
  • the gemstones are then fixed onto a carrier. For example, this may be achieved by transferring the gemstones from the sieving plate / centricity plate to a vacuum plate and then applying on the gemstones a plate of thermoplastic material in a plastic state such that the gemstones are at least partially embedded in the carrier.
  • the carrier is made from or comprises an elastic material, such as e.g. a rubber-like material. Some elasticity in the carrier may advantageously help to compensate for differences in the level (height) of the surface to be imprinted, between the gemstones on the carrier.
  • the carrier is made from or coated with a material that has chemical resistance to the chemicals used in the production process (including e.g. any coatings, cleaning agents, etc.) and to the process parameters used during production (e.g. temperature, humidity etc.).
  • the carrier is preferably made from or comprises a material that enables the fixation of the gemstones in the x, y and z directions (using an adhesive or by embedding the gemstones in the material, as explained above).
  • the layer of imprintable material is imprinted using the working stamp, for example, provided on a roller.
  • the decorative bodies on their carrier and the stamps on their support may, if necessary, be aligned by relative movement of the support and carrier, for example using one or more mechanical stop onto which the carrier (or a structure supporting the carrier) can be pushed.
  • the microstructure geometry is designed such that rotational alignment between the gemstones and the working stamps is not necessary, as explained above.
  • the imprintable material may be provided on the gemstone (standard NIL) or on the working stamps (reverse NIL, see for example, X. D. Huang, et al.: Reversal imprinting by transferring polymer from mold to substrate, J. Vac. Sci. Technol., B, Vol. 20, 2078, 2002 ).
  • the imprintable material is cured.
  • the imprintable material is a light (e.g. UV) curable resin
  • the resin may be cured through the stamp and/or through the support by exposing the resin to electromagnetic (e.g. UV) radiation.
  • the imprintable material is cured at the same time as (simultaneously with) imprinting, in order to reduce the risk of reflow of the imprintable material and/or the risk of the imprintable material adhering to the stamp.
  • the imprinting material is cured at least partially by exposing the imprintable material to electromagnetic radiation through the support. This may advantageously remove requirements on the stamp to be transparent to the electromagnetic radiation used.
  • the decorative elements according to the invention are particularly suitable for use on garments, wearables, fashion accessories, etc. where the combination of a flat back surface as well as the aesthetic potential afforded by the use of a decorative element with improved ⁇ gem-like' optical properties are important.
  • gemstones with flat backs were studied for their optical properties.
  • Figure 8A shows a schematic front side perspective view of a flat back gemstone 1000 according to the prior art, with a simple cut (referred to as 'A2000 cut') comprising a single set of crown facets 1100 extending between a table 1200 and a girdle 1400.
  • Figure 8B shows a schematic front side perspective view of a flat back gemstone 1000' according to the prior art, with an advanced cut (referred to as 'A2078 cut') comprising a first and second set of crown facets 1100', 1300' extending between a girdle 1400' and a flat table 1200'.
  • the gemstone 1000 has a diameter of 3.1 mm; a girdle height of 0.31 mm; and the table 1200 has a shortest diameter of 1.55 mm. Facets 1100 have an angle of 42.0° relative to the plane of the girdle.
  • the gemstone 1000' has a diameter of 3.1 mm, a girdle height of 0.18 mm height, and the table 1200' has a shortest diameter of 1.15 mm.
  • Facets 1300' have an angle of 34.2° relative to the plane of the girdle, and facets 1100' have an angle of 40.7° relative to the plane of the girdle.
  • the gemstone 1000" has a diameter of 3.1 mm, a girdle height of 0.245 mm height, and the table 1200" has a shortest diameter of 1.242 mm. Facets 1100" have an angle of 25.0° relative to the plane of the girdle.
  • the gemstone 1000′′′ has a diameter of 3.1 mm, a girdle height of 0.328 mm height, and the table 1200′′′ has a shortest diameter of 1.109 mm. Facets 1100'", 1300′′′ have an angle of 42° relative to the plane of the girdle.
  • the table facet 1200, 1200', 1200" and 1200′′′ has an angle of 0° to the girdle plane.
  • a directed white light source illuminating the gemstone from the top through an aperture of 2x0.25°, i.e. 0.5° was used.
  • the coloured reflections on an observing surface (a 1 m ⁇ 1 m flat observing surface placed parallel to the girdle plane and at 0.5 m above the girdle plane), from the light incident on the gemstone were analysed.
  • Figure 9 shows the quantified fire value (relative to the maximum fire possible) and light return value (relative to the light return of Spectralon ® ) for the cuts of Figure 8A (A2000), Figure 8B (A2078), Figure 8C (A2034) and Figure 8D (A2038).
  • flat back gemstones according to the prior art have light return values of about 45% for simple cuts like that of Figure 8A , and about 50-70% for advanced cuts such as those of Figures 8B, 8C and 8D .
  • gemstones according to the prior art have fire values in the range of about 30% for simple cuts like that of Figure 8A , and about 35-50% for advanced cuts such as those of Figures 8B, 8C and 8D .
  • the pattern of light reflections associated with the gemstone of Figures 8A, 8B and 8C were also simulated for shallow, intermediate and steep-angle light, as explained above in relation to Figure 2 .
  • Figures 11A, 11B, 11C and 11D show the pattern of light reflections associated with the gemstone of Figure 8B .
  • Figure 11A shows the pattern of light reflections from shallow angle light
  • Figure 11B shows the pattern of light reflections from intermediate angle light
  • Figure 11C shows the pattern of light reflections from steep angle light
  • Figure 11D shows the combined light reflections from shallow, intermediate and steep angle light.
  • the gemstone 1000' comprised a smaller compact steep-angle light area in the centre of the gemstone (see Figure 11C ) compared to gemstone 1000 of Figure 8A , but this was still relatively large (about 1.15-1.2 mm). Additionally, the steep-angle light areas were not distributed in a star-like pattern (see Figure 11C ).
  • Figures 12A, 12B, 12C and 12D show the pattern of light reflections associated with the gemstone of Figure 8C .
  • Figure 12A shows the pattern of light reflections from shallow angle light
  • Figure 12B shows the pattern of light reflections from intermediate angle light
  • Figure 12C shows the pattern of light reflections from steep angle light
  • Figure 12D shows the combined light reflections from shallow, intermediate and steep angle light.
  • the gemstone 1000" comprised a large compact steep-angle light area in the centre of the gemstone (see Figure 12C ) compared to gemstone 1000 of Figure 8A , and gemstone 1000' of Figure 8B . Additionally, the steep-angle light areas were not distributed in a star-like pattern (see Figure 12C ).
  • the inventors sought to improve on the flat back gemstones of the prior art (Example 1), by providing decorative elements according to the invention, which combine the gemstones of the prior art with a microstructure and reflective layer.
  • Microstructure geometry was designed to optimise the brilliance (fire and light return) of the decorative element for each gemstone cut.
  • Figure 13A shows a perspective view of a microstructure according to an embodiment of the invention.
  • Figure 13B is a diagram that shows the pattern of grooves that was used to create the geometry shown on Figure 13A .
  • nine identical triangular grooves with a first planar wall inclined at an angle of 5.4° and a second planar wall inclined at an angle of 14.6° were created.
  • Each groove was located with the first planar wall nearer the centre of the microstructure, and at a distance L R from the centre of the structure, where L R is equal to 64.5% the radius of the microstructure.
  • Each groove was rotated by 40°, producing a pattern that has nine-fold rotational symmetry.
  • Figures 15A, 15B, 15C and 15D show the pattern of light reflections associated with the decorative element of Figure 14.
  • Figure 15B shows the pattern of light reflections from shallow angle light
  • Figure 15C shows the pattern of light reflections from intermediate angle light
  • Figure 15D shows the pattern of light reflections from steep angle light
  • Figure 15A shows the combined light reflections from shallow, intermediate and steep angle light.
  • the decorative element of Figure 14 has about 13.2% of steep angle light reflection areas (compared to an ideal of about 15%, and about 32% for the gemstone of Figure 8A ), with 82.2% intermediate and 4.6% of shallow light reflections (compared to 64% and 4% for the gemstone of Figure 8A ). Whilst the total amount of light return is not necessarily significantly higher than for the corresponding prior art gemstone at all angles (shallow, medium, high), the distribution of light return for the gemstone of the invention ( Figure 14 ) is more visually pleasing, in comparison to the prior art, as is clear from the comparison of Figures 10A to 10D against Figures 15A to 15D for the gemstone of the invention.
  • Figure 16A shows a perspective view of a microstructure according to an embodiment of the invention.
  • Figure 16B is a diagram that shows the pattern of grooves that was used to create the geometry shown on Figure 16A .
  • nine identical triangular grooves with a first planar wall inclined at an angle of 8.2° and a second planar wall inclined at an angle of 4.9° were created.
  • Each groove was located with the first planar wall towards / nearest the centre of the microstructure, and at a distance L R from the centre of the structure equal to 88.6% the radius of the microstructure.
  • Each groove was rotated by 40°, producing a pattern that has nine-fold rotational symmetry.
  • Figures 18A, 18B, 18C and 18D show the pattern of light reflections associated with the decorative element of Figure 17.
  • Figure 18B shows the pattern of light reflections from shallow angle light
  • Figure 18C shows the pattern of light reflections from intermediate angle light
  • Figure 18D shows the pattern of light reflections from steep angle light
  • Figure 18A shows the combined light reflections from shallow, intermediate and steep angle light.
  • Figure 19A shows a perspective view of a microstructure according to an embodiment of the invention.
  • Figure 19B is a diagram that shows the pattern of grooves that was used to create the geometry shown on Figure 19A .
  • six identical triangular grooves with a first planar wall inclined at an angle of 5.3° and a second planar wall inclined at an angle of 7.9° were created.
  • Each groove was located with either the first planar wall or the second planar wall towards the centre of the microstructure, i.e.
  • Figures 21A, 21B, 21C and 21D show the pattern of light reflections associated with the decorative element of Figure 20.
  • Figure 21B shows the pattern of light reflections from shallow angle light
  • Figure 21C shows the pattern of light reflections from intermediate angle light
  • Figure 21D shows the pattern of light reflections from steep angle light
  • Figure 21A shows the combined light reflections from shallow, intermediate and steep angle light.
  • Figure 22A shows a plan view of a microstructure according to another embodiment of the invention.
  • Figures 22B and 22C show the stamp parts that were used to create the geometry shown on Figure 22A .
  • a faceted pyramid with 7-fold rotational symmetry and a radius of 63.8% of the radius of the gemstone was combined with a flat outer ring.
  • the latter part can for example be obtained using a monocrystalline diamond tool, as explained above.
  • Each of the facets of the pyramid had an angle of 11.2° relative to the flat back surface of the gemstone.
  • the microstructure shown on Figure 22A was combined with the gemstone of Figures 8A, 8B and 8C .
  • Figure 23 shows the appearance of a gemstone according to Figure 8B combined with the faceting arrangement of Figure 22A .
  • the resulting decorative element has a light return of 39.36% and a fire of 46.03% - compared to about 55% and about 48%, respectively, for the corresponding flat back gemstone according to the prior art.
  • Figures 24A, 24B, 24C and 24D show the pattern of light reflections associated with the decorative element of Figure 23.
  • Figure 24B shows the pattern of light reflections from shallow angle light
  • Figure 24C shows the pattern of light reflections from intermediate angle light
  • Figure 24D shows the pattern of light reflections from steep angle light
  • Figure 24A shows the combined light reflections from shallow, intermediate and steep angle light.

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Claims (15)

  1. Un élément décoratif (400) comprenant :
    un corps décoratif à facettes (100) avec une surface arrière plane (150),
    une microstructure (200) sur la surface arrière plane (150) du corps décoratif (100), où la microstructure (200) comprend une zone à facettes (220A), et
    une couche au moins partiellement réfléchissante (240) sur au moins une partie de la zone à facettes (220A) de la microstructure (200),
    où la combinaison de la zone à facettes (220A) et de la couche au moins partiellement réfléchissante (240) est configurée de façon à réfléchir une lumière incidente sur la couche au moins partiellement réfléchissante (240) au travers du corps décoratif (100) et/ou de la microstructure (200) dans une pluralité de directions.
  2. L'élément décoratif (400) selon la Revendication 1, où : la microstructure (200) possède une hauteur (HM) inférieure à 1 000 µm, inférieure à 500 µm, inférieure à 300 µm, inférieure à 200 µm, et/ou d'au moins 10 µm, d'au moins 20 µm, d'au moins 30 µm, d'au moins 40 µm ou d'au moins 50 µm ou d'au moins 100 µm, éventuellement où la zone à facettes (220A) est créée par des parties à facettes concaves de la microstructure (200).
  3. L'élément décoratif (400) selon la Revendication 1 ou 2, où les facettes (230) de la zone à facettes (220A) ou des parties à facettes concaves de la microstructure (200) possèdent une profondeur située entre 1 µm et 1 000 µm, entre 5 µm et 500 µm, entre 10 µm et 400 µm, entre 20 µm et 300 µm, entre 30 µm et 200 µm ou entre 40 µm et 100 µm.
  4. L'élément décoratif (400) selon l'une quelconque des Revendications précédentes, où les facettes (230) dans la zone à facettes (220A) sont chacune inclinées par rapport à la surface arrière plane (150) du corps décoratif à facettes (100) d'un angle (α, β) entre 1° et 30°, entre 2° et 25°, entre 3° et 20° ou entre environ 4° et environ 16°, éventuellement où chacune des facettes (230) est inclinée par rapport à la surface arrière plane (150) du corps décoratif à facettes (100) de sensiblement le même angle (α, β), ou où les angles (α, β) entre les facettes (230) dans la zone à facettes (220A) et la surface arrière plane (150) du corps décoratif à facettes (100) sont sélectionnés parmi un angle de deux angles (α, β).
  5. L'élément décoratif (400) selon l'une quelconque des Revendications précédentes, où la zone à facettes (220A) de la microstructure (200) comprend une pluralité de facettes (230) de la forme d'une pyramide, où chaque facette (230) est formée d'une paroi planaire (28, 28b) de la pyramide, et l'angle (α, β) entre chacune des parois planaires (28, 28b) de la pyramide et la surface arrière plane (150) du corps décoratif (100) est sélectionné individuellement parmi entre 1° et 30°, entre 2° et 25°, entre 3° et 20° ou entre 4° et 16°, de préférence, où l'angle (α, β) est le même pour chaque facette (230) de la pyramide.
  6. L'élément décoratif (400) selon la Revendication 6, où la pyramide possède entre 4 et 13 faces planaires, entre 5 et 12 faces planaires ou entre 6 et 11 faces planaires, éventuellement où les facettes (230) de la pyramide sont d'une taille égale, ou où les facettes (230) de la pyramide sont de deux ou plus tailles différentes.
  7. L'élément décoratif (400) selon l'une quelconque des Revendications 1 à 5, où la zone à facettes (220A) de la microstructure (200) comprend une pluralité de rainures (28) créant un motif de facettes (230) où les rainures (28) comprennent deux parois planaires (28, 28b), et les angles (α, β) entre chacune des parois planaires (28, 28b) des rainures (28) et la surface arrière plane (150) du corps décoratif (100) sont sélectionnés individuellement parmi entre 1° et 30°, entre 2° et 25°, entre 3° et 20° ou entre 4° et 16°.
  8. L'élément décoratif (400) selon la Revendication 8, où la pluralité de rainures (28) sont pivotées les unes par rapport aux autres par :
    (i) un angle constant autour d'un point central du corps décoratif (100), et sont placées les unes par rapport aux autres de façon à former un motif symétrique rotatif à n plis, ou
    (ii) deux ou plus angles différents autour d'un point central du corps décoratif (100), et la pluralité de rainures (28) définissent un motif possédant une symétrie rotationnelle où le degré de symétrie rotationnelle est inférieur au nombre de rainures (28).
  9. L'élément décoratif (400) selon l'une quelconque des Revendications précédentes, où la zone à facettes (220A) comprend un motif de facettes (230) qui possède une symétrie rotationnelle à n plis et où le corps décoratif à facettes (100) possède une symétrie rotationnelle à m plis, et m est un entier différent de n, éventuellement où les nombres n et m sont sélectionnés indépendamment de façon à être entre 4 et 13, entre 5 et 12 ou entre 6 et 11, comme par exemple 6, 7, 8, 9, 10 ou 11.
  10. L'élément décoratif (400) selon l'une quelconque des Revendications précédentes, où les facettes (230) de la microstructure (200) sont des surfaces planaires avec une rugosité de surface faible et un degré de planéité élevé, éventuellement où la rugosité de surface est inférieure à 100 nm, inférieure à 50 nm, inférieure à 20 nm, inférieure à 10 nm ou inférieure à 5 nm, et/ou la planéité présente un écart de planéité dε inférieur à 2 µm, inférieur à 1 µm, inférieur à 800 nm, inférieur à 500 nm ou inférieur à 250 nm.
  11. L'élément décoratif (400) selon l'une quelconque des Revendications précédentes, où :
    (i) la microstructure (200) est formée à partir d'une couche de matériau appliquée sur la surface arrière plane (150) du corps décoratif à facettes (100), ou
    (ii) où la microstructure (200) est formée d'un seul tenant avec le corps décoratif à facettes (100),
    où la microstructure (200) est formée à partir d'un matériau qui possède un indice de réfraction qui est à moins de 30%, à moins de 20%, à moins de 10% ou à moins de 5% de celui du matériau du corps décoratif (100),
    éventuellement où la partie à facettes de la microstructure (200) est formée par une impression de la surface arrière plane (150) du corps décoratif à facettes (100) ou d'une couche ou d'un matériau appliqué sur la surface arrière plane (150) du corps décoratif à facettes (100), comme par exemple par impression lithographique.
  12. L'élément décoratif (400) selon l'une quelconque des Revendications précédentes, où la microstructure (200) et/ou le corps décoratif (100) est/sont fabriqué(s) à partir d'un matériau transparent, éventuellement où le corps décoratif à facettes (100) est une pierre gemme, par exemple, où la pierre gemme se compose de verre, de verre de cristal, de vitrocéramique, de plastique ou de zirconium cubique.
  13. L'élément décoratif (400) selon l'une quelconque des Revendications précédentes, comprenant en outre une ou plusieurs couches de protection (250) sur la couche au moins partiellement réfléchissante (240), et/ou éventuellement comprenant en outre une couche adhésive sur la couche de protection (250) ou la couche au moins partiellement réfléchissante (240).
  14. Un procédé de fabrication d'un élément décoratif (400), le procédé comprenant :
    la fourniture d'un corps décoratif à facettes (100) possédant une surface arrière plane (150),
    la formation d'une microstructure (200) sur la surface arrière plane (150) du corps décoratif (100), où la microstructure (200) comprend une zone à facettes (220A),
    la formation d'une couche au moins partiellement réfléchissante (240) sur au moins une partie de la zone à facettes (220A) de la microstructure (200), où la combinaison de la zone à facettes (220A) et de la couche au moins partiellement réfléchissante (240) est configurée de façon à réfléchir une lumière incidente sur la couche au moins partiellement réfléchissante (240) au travers du corps décoratif (100) dans une pluralité de directions.
  15. Le procédé selon la Revendication 14, où :
    (i) la formation d'une microstructure (200) sur la surface arrière plane (150) du corps décoratif (100) comprend l'application d'une couche de matériau imprimable et l'impression d'une microstructure (200) dans la couche de matériau imprimable au moyen d'une estampille, éventuellement où le procédé comprend en outre le durcissement du matériau imprimable, ou
    (ii) la fourniture d'un corps décoratif (100) comprenant une surface avant et une surface arrière, et la formation d'une microstructure (200) sur la surface arrière plane (150) du corps décoratif (100) comprend la formation de la microstructure (200) et d'une zone à facettes (220A) d'un seul tenant avec le corps décoratif (100), par exemple, au moyen d'un procédé de fabrication sol-gel, par une fabrication additive (par exemple une impression 3D) ou par moulage par injection.
EP20807288.4A 2019-10-30 2020-10-21 Élément décoratif Active EP4051047B1 (fr)

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EP19206351.9A EP3815566A1 (fr) 2019-10-30 2019-10-30 Élément décoratif
PCT/EP2020/079670 WO2021083772A1 (fr) 2019-10-30 2020-10-21 Élément décoratif

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Publication number Priority date Publication date Assignee Title
US2511510A (en) * 1948-02-03 1950-06-13 Ralph S Mukai Artificial asteria
GB2197162B (en) 1986-10-23 1991-03-27 Plessey Co Plc Decoding of convolutional encoded signals
DE8701681U1 (fr) * 1987-02-04 1987-07-09 Moeck H Sbm Bernstein Mannf Ohg
AT414310B (de) 2004-03-19 2007-01-15 Swarovski & Co Blei- und bariumfreies kristallglas
EP2289361A1 (fr) * 2005-12-06 2011-03-02 California Institute of Technology Amélioration des caractéristiques optiques d'une pierre précieuse
AT514332B1 (de) 2013-08-27 2014-12-15 Swarovski D Kg Anordnung zur Analyse eines durch Brechung und Reflexion an einem Schmuckstein hervorgerufenen Lichtmusters
EP3141142A1 (fr) * 2015-09-09 2017-03-15 D. Swarovski KG Pierre decorative a couleur modifiable

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EP4051047A1 (fr) 2022-09-07
WO2021083772A1 (fr) 2021-05-06

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