GB2533097A

GB2533097A - Creating optical effects

Info

Publication number: GB2533097A
Application number: GB1421823.4A
Authority: GB
Inventors: Behrens Steven
Original assignee: CRYSTAL CLEAR JEWELLERY Ltd
Current assignee: CRYSTAL CLEAR JEWELLERY Ltd
Priority date: 2014-12-08
Filing date: 2014-12-08
Publication date: 2016-06-15
Also published as: GB201521596D0; GB2535292A; GB201515283D0; GB2533182A; WO2016092288A1; GB2535561A; GB201421823D0; GB201512811D0

Abstract

A translucent stone cluster effect article for jewellery having a smooth first face (12) which is not faceted and parallel back face (13) which faceted projections (14). Light (Ri) incident on the first face suffers total internal reflection on at least two facets (14b) of at least one protuberance (14) and leaves through the first face (12). The article may be transparent and may be made from synthetic sapphire, cubic zirconia or moissanite. The projections may have triangular, rectangular, square, hexagonal, octagonal or other polygonal bases. The projections may be similar and in uniform array, or different shapes or arranged irregularly, or have shapes corresponding to conventional stone cuts. The projections may be on a flat, curved or spherical surface. The projections may be spaced by between 2 and 4 millimetres. The projections may be formed by machining the face, or moulding. Ideally, moulded projections are finished mechanically.

Description

Creating Optical Effects This invention relates to creating optical effects, particularly, but not exclusively, in small objects such as jewellery, miniature objets de vertu and objets d 'an.

Jewellery features precious and semi-precious stones, most often transparent, and faceted to sparkle by splitting light into rainbow colours or reflecting light from the facets. Precious stones are characterised by high refractive index, more effective at sparkling, but semi-precious stones, glass, particularly flint glass, and even plastics, particularly acrylics, can be used to good effect.

The 'cut' of a precious or semi-precious stone, its finished shape, is to some extent dictated by its crystal structure presenting preferred lines of cleavage, but the lapidary also has regard to hiding imperfections and the way light is refracted and reflected by the faceting, and, of course, the way the stone fits into the design of the piece in which it is to be mounted. Classic cuts include round, baguette, rose, heart, princess, and these are copied into glass and plastic, the general idea being to make the cheaper 'stones' resemble the precious stones as closely as possible.

The back of a stone, known as the 'pavilion' is of importance for the sparkle as the front, or 'crown' -the pavilion is where light incident on the crown is internally reflected so that it emerges from the crown after diffraction. The crown, the front of the stone, is where the light is refracted, and split into colours because of the different refractive indices for different wavelengths.

Stones, of whatever material, are conventionally mounted in a piece of jewellery, a ring, a brooch, a pendant, which must have provision for holding stones securely and without impeding the sparkle, and this is important when stones are clustered. The usual cluster mount involves claw structures, one per stone, which should, in many designs, when the piece is assembled, be barely visible, or not visible at all -termed a pave setting. Making these structures fine, but strong, so that stones do not fall out, especially in soft metals such as gold and silver, involves intricate craftsmanship.

Stone clusters, precious or otherwise, also feature in decorative objects, not necessarily for personal adornment, such as etuis, decorated 'eggs', and like objects that can be classed as miniature objets de verttt and objets d 'an.

The present invention provides new ways for creating optical effects in jewellery, and miniature objets de vents and objets. d'art.

The invention comprises a translucent stone cluster effect article having substantially parallel faces, comprising a relief pattern of faceted projections on its back face the other, front face being unfaceted, the number of faceted projections, the distance d between the parallel faces and the refractive index n of the article being such that light incident at at least one angle on the unfaceted face will refract so as to strike at least two facets of at least one projection of the faceted face at greater than the critical angle and be totally internally reflected so as to emerge from the unfaceted face.

The article may be transparent, and may be clear or coloured.

The projections may be pyramidal or frusto-pyramidal in form, and may have triangular, rectangular, particularly square, hexagonal, octagonal or other polygonal bases. The projections may be similar and in uniform array. Or the projections may he of different shapes and/or arranged irregularly. At least some projections may have more complex shapes corresponding to known gemstone crown designs, including one or more of kite facets and star facets.

The projections may be on a flat face or a curved, e.g. part-spherical face. When the front face is curved, the back face may be planar or curved The projections may be spaced by a small number of millimetres, particularly between 2 and 4 millimetres, 3 millimetres giving excellent effects.

The projections may be formed by machining the face, or by moulding, though when 20 moulded, the projections may be finished mechanically to polish facets and sharpen edges.

The article may comprise a piece of jewellery or an objet de vertu or objet d'art per se, or may be a component of such a piece or OM. Thus, a heart-shaped article may have a heart-shaped array of projections on one face, surrounded by a flat border, and be pierced to receive a chain to be worn as a pendant. Or an article may be mounted in a larger setting, in a metal, e.g, precious metal, frame or claw structure, with or without another such article or articles and individual stones.

While not having the usual combination of crown and pavilion in individual stones, cluster effect articles according to the invention display excellent sparkle and are easier to mount and offer more design possibilities than when individual stones are mounted in a pave design.

Articles made from high refractive index materials are particularly effective. Synthetic sapphire, cubic zirconia, and moissanite can all be used to good effect.

Translucent stone cluster effect articles according to the invention will now be described with reference to the accompanying drawings, in which: Figure I is a view of one article formed as a pendant; Figure 2 is a section on the line 11-11 of Figure 1; Figure 3 is a view of an article like that of Figure 1, differently faceted, Figure 4 is a section on the line TV-IV of Figure 3 Figure 5 is a view of an article used in a finger ring; and Figure 6 is a section on the line VI-VI of Figure 5; The drawings illustrate translucent stone cluster effect articles 11, each having substantially parallel faces 12, 1 3, comprising a relief pattern of faceted projections 14 on its back face 13, the other, front face 12 being unfaceted, the number of faceted projections 14, the distance d between the parallel faces and the refractive index n of the article 11 being such that light incident at at least one angle on the unfaceted face 12 will refract so as to strike at least two facets of at least one projection 14 of the faceted face 13 at greater than the critical angle and be totally internally reflected so as to emerge from the unfaceted face 12.

In the embodiment of Figures 1 and 2,the projections 14 are essentially pavilions of individual gemstones, having Quiets 14a and main facets 14b.

Incident and emergent rays Ri, Re are shown in Figure 2, the incident ray Ri being refracted at the front face 12, totally internally reflected at a main facet 14b of projection 14 onto the culet 14a, totally internally reflected again on to the opposite main facet 14b, emerging through face 12 where it is again refracted.

The embodiment of Figures 3 and 4 is like that of Figures 1 and 2, but having fully pyramidal projections 14. These projections 14 are shallower than those of Figures 1 and 2, so that the ray is totally internally reflected off one main facet 14b onto the opposite main facet 14b, thence emerging through face 12.

At each refraction, of course, at the front face 12, the ray is split into rainbow colours.

The articles 11 can be translucent or transparent, and can be clear or coloured, so that incident light can be refracted and reflected, both internally and from the facets of the projections 14.

The projections 14 illustrated are pyramidal or frusto-pyramidal in form, and have square bases, but rectangular, hexagonal, octagonal or other bases can be used. In the square pendant 11 of Figures 1 to 4, the projections 14 are similar and in uniform array.

In the embodiment of Figures 5 and 6, the projections 14 are of different sizes, and the faceted face 13 is curved. However, projection shapes can be different and/or arranged irregularly. The illustrated projections 14 have shapes corresponding to pavilions of known gemstone cuts, but, so long as it is capable of being cast or moulded, or mechanically produced as by machining or by laser cutting, any shape can be adopted. The projections can be spaced one from the next by a small number of millimetres -Figure 3 indicates a scale -and particularly between 2 and 4 millimetres, 3 millimetres giving excellent effects.

The projections 14 can be formed by machining the face 13, or by moulding, though when moulded, the projections can be finished mechanically to flatten facets and sharpen edges, whereby to increase a sparkle effect.

The articles 11 can comprise a piece of jewellery or an objet de vertu or objet d'art per se, or may be a component of such a piece or objet. Thus, the square article 11 of Figure 1 has a square array of projections 14 on one face 13, surrounded by a flat border 15. It has a pierced lug 16 to receive a chain 17 to be worn as a pendant Articles 11 made from high refractive index materials are particularly effective. Synthetic sapphire, cubic zirconia, and moissanite can all be used. Plastics, particularly high refractive index plastics such as acrylics, can be used to make attractive and inexpensive jewellery and small decorative objects.

While machining and moulding have been mentioned as manufacturing techniques, hand crafting may well be appropriate for high value items. Other techniques might also be used, depending on the nature of the material involved, such as sintering, high definition 3D printing, laser cutting and spark erosion.

Claims

Claims: A translucent stone cluster effect article having substantially parallel faces, comprising a relief pattern of faceted projections on its back face the other, front face being unfaceted, the number of faceted projections, the distance d between the parallel faces and the refractive index n of the article being such that light incident at at least one angle on the unfaceted face will refract so as to strike at least two facets of at least one projection of the faceted face at greater than the critical angle and be totally internally reflected so as to emerge from the unfaceted face.
An article according to claim 1which is transparent.
3 An article according to claim I or claim 2, in which the projections are pyramidal or frusto-pyramidal in form.
4 An article according to claim 3, in which the projections have triangular, rectangular, particularly square, hexagonal, octagonal or other polygonal bases.
An article according to any one of claims 1 to 4, in which the projections are similar and in uniform array.
6 An article according to any one of claims 1 to 4, in which the projections are of different shapes and/or arranged irregularly.
7 An article according to any one of claims 1 to 6, in which at least some projections have shapes corresponding to conventional stone cuts.
8 An article according to any one of claims I to 7, in which the projections are on a flat face.
9 An article according to any one of claims I to 7, in which the projections are on a curved, e.g. part-spherical face.
An article according to any one of claims I to 9, in which the projections are spaced one from the next by a small number of millimetres.
11 An article according to claim 10, in which the projections are spaced one form the next by between 2 and 4 millimetres.
12 An article according to any one of claims 1 to 11, in which the projections are formed by machining the face.
13 An article according to any one of claims 1 to 11, in which the projections are formed by moulding.
14 An article according to claim 13, in which moulded projections are finished mechanically to flatten facets and sharpen edges.
An article according to any one of claims I to 14, comprising a piece of jewellery or an objet tie vertu or objet d 'art per se, or a component of such a piece or objet.
16 An article according to claim 15, made from a high refractive index material such as synthetic sapphire, cubic zirconia, or moissanite.