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    • 专利摘要:
    A method for determining a cut shape for a gemstone, comprising selecting a generic shape for the cut shape; simulating a plurality of optical quantities for grinding mold designs using simulation models; selecting one or more grinding shape designs thereof based on the simulated optical quantities; cutting and polishing the gem using the optimized cut shape designs with the optimized geometry parameters.
    公开号:BE1020201A5
    申请号:E2011/0452
    申请日:2011-07-14
    公开日:2013-06-04
    发明作者:Garry Holloway
    申请人:Octonus Dia Tech Private Ltd；
    IPC主号:
    专利说明:

    Method for determining a cut shape for a precious stone
    Technical field
    The present invention relates to the field of cut shape optimizations for a gemstone.
    State of the art US 2006/0074588 describes a system for determining the value of a grinding mold using a number of variables with regard to the appearance of the stone to generate scores for a number of grinding mold components that influence the grinding mold quality.
    Summary of the invention
    The invention relates to a method for determining a cut shape for a gemstone. According to an embodiment, the method comprises the following steps. First, a generic shape for the cut is chosen. Next, multiple grinding mold designs (i.e., grinding mold models) with the selected generic shape are selected, for example, a number of commercially available grinding mold designs with the generic shape. Thereafter, a number of optical quantities ("metrics") are simulated for the multiple grinding shape designs using a number of simulation models with model coefficients. On the basis of the simulated optical quantities, one or more grinding shape designs of the multiple grinding shape designs are selected for further optimization. The geometry parameters for each selected cut shape design are varied within a range and a number of optical quantities are simulated for this range of geometry parameters. A further optimized cut shape design with optimized geometry parameters is determined based on the simulation results. Thereafter, the gemstone is polished using the further optimized cut shape design with the optimized geometry parameters, after which the visual appearance of the polished gemstone is analyzed. Based on the visual appearance analysis, the simulation models and / or the model coefficients can be adjusted and / or the range for varying the geometry parameters can be changed and / or a cut shape design of the multiple cut shape designs can be adjusted, and / or one or more new cut designs are added to the set of cut designs. These steps can be repeated a number of times to increase the accuracy and effectiveness of the method according to the invention.
    The generic form can for example be one of the following generic forms: cushion, round, princess, emerald, asscher, oval, marquis, pear, radiant, heart.
    The geometry parameters can include typical crown and pavilion parameters that are used to characterize the cut shape. For a cushion, these can be, for example, the crown angle, the pavilion main facet corner, the pavilion depth, the number of star facets, the depth of the lower facets, and other parameters that are known to those skilled in the art.
    The number of optical quantities can include one or more of the following: light reflection ("brilliance"), fire ("fire"), glare ("scintillation"), life ("life"), a light-independent probabilistic optical quantity, a dark zone quantity.
    The light reflection or brilliance of a gemstone is a measure of the brightness of the gemstone in certain light conditions and is dependent on the brightness and contrast. In other words, the light reflection is the ability of the gem to reflect a fraction of the incident light to the eye of an observer along with attractive contrasting scattered dark areas.
    The fire of a gemstone depends on the brilliance and the dispersion (refraction). Fire is generally considered to be a measure of the ability of the diamond to disperse a white light in spectral iridescent colors observed by the observer.
    The life of a gemstone depends on the fire and the sparkle (the amount of "sparkle" that flashes on and off as bright and dark zones) of the gemstone.
    A dark zone quantity is a quantity that qualifies the amount of light that reflects the shape of the cut from the directions where there is no reality with no light sources. An analysis of the dark zones is based on the idea that it is necessary to model light from directions where there is actually no light, such as regions shielded by an observer's head and body, and the background (the lower hemisphere). below the face).
    The light-independent probabilistic optical quantity may, for example, be an effective total angle-size quantity that uses simulated light spots on a surface that result from a calculation of a portion of the space visible through the grinding shape. This part of the space is formed by a plurality of cones converging in the eye of an observer through the cut, each cone comprising a light source. The effective total angle magnitude can include one or more of the following: a monochrome effective total angle size that takes into account the amount of light spots, a fire-effective total angle size that only takes into account colored light spots, a dynamic effective total angle size that takes into account changing of the position of the light spots on the surface when the cut is tilted. Other examples will be given in the embodiments illustrated in the figures, and in the claims.
    According to a further embodiment, the number of optical quantities can further comprise a value determination quantity which takes into account one or more of the following effects: fish eye (nail), nail (light head), light leaks, dark zones with a negative visual appearance.
    The simulation models used to simulate the optical quantities preferably take into account the stereo-visual effect and / or optical limitations of the human eye such as light effects that are too small or too weak to be perceptible.
    According to an embodiment, analyzing the visual appearance of the polished gemstone includes attaching the gemstone in a container, and moving the gemstone back and forth in different light conditions to examine and measure light reflection, fire and life.
    According to an embodiment, adjusting a grinding shape design consists of adding or removing one or more facets of the grinding shape design. The addition of a new grinding mold design may consist of adding a grinding mold design with a number of facets that is different from the number and / or location of the facets of each of the plurality of grinding mold designs, for example by dividing or breaking a plurality of facets.
    According to a further developed embodiment, simulating a plurality of optical quantities for the plurality of grinding shape designs includes using model coefficients, simulating a first plurality of optical quantities for a first zone of each grinding shape design of the plurality of grinding shape designs and a second plurality of optical quantities for a second zone thereof. These optical quantities will be described in more detail in the figure description. For certain generic shapes or for certain grinding shape designs of a generic shape, it may be decided, for example, to simulate the number of optical quantities for the table on the one hand and for the crown without a table on the other.
    The invention also relates to a computer program product comprising programming code for determining a cut of a gemstone, which programming code comprises instructions for performing one or more of the steps of one of the above described embodiments of the method.
    The invention further relates to a stone made from a (semi) precious stone material, more in particular from natural or synthetic diamond, wherein the stone is cut and polished according to an abrasive shape that has been determined using an embodiment of the method described above. .
    The invention relates in particular to a stone according to any one of claims 17-44. The grinding shapes of the claimed stones have the advantage that they show better results for the optical quantities, the comparison being made using the optimized simulation models and model coefficients to calculate these optical quantities.
    BRIEF DESCRIPTION OF THE FIGURES
    The attached figures are used to illustrate current non-limiting preferred embodiments of the present invention. The above described and other advantages, features and objects of the invention will become more apparent, and the invention will be better understood from the following detailed description when read together with the attached drawings, in which:
    Figures 1A and 1B show an ETAS and a DETAS graph for a round brilliant cut (RBC);
    Figure 2 illustrates an observer model showing a diamond facet that acts as an additional diaphragm for the pupil for a light source;
    Figure 3 shows an example of flashes with and without fire potential;
    Figure 4 ETAS graphs shows a 1.00 kt Tolkowsky RBC on the left and a 10.00 kt on the right; Figure 5 shows a table with geometry ratios and light reflection / ETAS fire quantities for different square cushion designs;
    Figure 6 is a light reflection / monochrome ETAS graph for the cut designs of the table of Figure 5;
    Figure 7 illustrates the optimized CushionP design and shows bottom and top views of the cut shape design, a simulated photo-realistic image and an ETAS graph; Figure 8 shows a simulated photorealistic image and an ETAS graph of the "MMS Cushion 1" (also called Cushion 1) symmetrical model (left) and the scanned model or actual polished Cushion 1 (right);
    Figure 9 shows an image of a Tolkowsky AGSO Heart and Arrow round brilliant and of the c state cut taken in a specially adapted lighting observation and photography box;
    Figures 10A and 10B illustrate the grinding mold designs Cushion 1 and Cushion 2, respectively;
    Figure 11 shows a chromatic dispersion chart for the "MSS Cushion 2";
    Figure 12 illustrates the Cushion 1 and 2 designs as well as a number of newly added models;
    Figure 13 illustrates the results of a user and expert vote between nine optimized shapes;
    Figure 14 illustrates the Cushion 1 and 2 designs as well as a number of newly added models and the further optimized Cushion 3, 4, 5 and 7 designs;
    Figure 15 shows images of a Tolkowsky RBC, a polished MSS Cushion 3 "," MSS Cushion 4 "and" MSS Cushion 5 "in a specially adapted lighting observation and photographing box;
    Figure 16 is a table containing optical quantities (Mono) for polished Cushions 1-7 for 1 kt stones;
    Figure 17 is a table containing optical quantities (Mono) for polished Cushions 1-7 for 10 kt stones;
    Figure 18 is a table containing optical quantities (Stereo / Tilt) for polished Cushions 1-7 for 1 kt stones;
    Figure 19 is a table containing optical quantities (Stereo / Tilt) for polished Cushions 1-7 for 10 kt stones;
    Figure 20 is a table showing the potential for dispersion in a ring for selected crown height and pavilion depth ranges;
    Figure 21 is a 3D graph illustrating an optical quantity as a function of the pavilion depth and crown height;
    Figure 22 shows the difference between the symmetrical Cushion 4 model and the scanned model of the actually polished Cushion 4; and
    Figure 23 shows a comparison of quantities between the symmetrical model and the actually polished Cushion 4 stone;
    Figure 24 schematically illustrates a first embodiment of a brick according to the invention;
    Figure 25 schematically illustrates a second embodiment of a brick according to the invention;
    Figure 26 Figure 25 illustrates schematically a third embodiment of a brick according to the invention;
    Figure 27 is a table containing optical variables (Mono) for polished Cushions 1-7 for 1 kt stones compared to three commercially available Cushion cut shapes;
    Figure 28 is a table containing optical quantities (Integral) for polished Cushions 1-7 for 1 kt stones compared to three commercially available Cushion cut shapes;
    Figure 29 is a table containing optical quantities (Stereo / Tilt) for polished Cushions 1-7 for 1 kt stones compared to three commercially available Cushion cut shapes.
    An embodiment of the method of the invention will now be illustrated in detail for an exemplary situation where it was decided that it is desirable to have a cushion cut. However, it will be understood by those skilled in the art that the method of the invention is equally well applicable to known other generic forms such as a round, a pear, etc., and to new forms.
    Typically, the purpose of an embodiment of the method of the invention is to find a cushion cut with maximum fire (typically at least greater than for a Tolkowsky RBC) and about the same brightness, while at the same time negative phenomena such as dark zones, fish eyes, etc. are avoided. The cut shape optimisations can be performed using software such as the one sold by the company OctoNus to simulate, for example, the special optical quantities that represent light reflection, contrast and fire, see below. Human stereo vision and optical limitations of the human eye are preferably taken into account. After optimization, the calculated optimized cut designs are cut out and polished and viewed by expert observers. The subjective valuation of the actual stones of observers is then taken into account to improve the following optimizations. An iterative process of these steps leads to a continuous design improvement, which results in an ever better functioning of the method. The grinding shapes that perform best can be further optimized for the commercial grinding of rough diamonds. The automated implementation of the method of the invention results in a reduction in the number of iterations with an actual cutting / polishing rating by a human being required to create a new cut with a desired optical appearance. The method of the invention lowers the time and financial cost required for developing a new grinding mold and also lowers the communication required between geographically separated grinding mold designers and developers.
    Before describing in detail the various steps of an embodiment of the method of the invention, the optical quantities that can be used in the method of the invention will be described, as well as the simulation models that can be used to calculate these optical quantities.
    Optical quantities
    Different light reflections from a 3D model of a gem can be calculated. There are typically three categories of relevant optical quantities: - reflections that are directly observed by the observer (glare, brilliance / light reflection, fire, where glare and fire determine the life of the gem); - a negative valuation by an observer (fish-eye, nail head, light leaks); - optical coefficients that evaluate the value of the cut regardless of the light and viewing conditions, such as the effective total angle, see below.
    The light reflection quantity calculates the brightness of the stone in certain light conditions. Light reflection depends on the light conditions used for the calculation. The light reflection quantity can for example be calculated using the OctoNus software called "Office". The light conditions in the simulation typically simulate a set of light sources that illuminate the diamond in the upper half sphere that surrounds the diamond. The observer does not emit light to the stone.
    Also for the viewing background for the stone it is typically assumed that it is black.
    An optical coefficient that is independent of the light and viewing conditions is ETAS (effective total angle size). ETAS is a simulation of a part of the space that an observer can see through the diamond. An observer sees the light in the diamond if a light source is placed within a cone that meets in our eye through the diamond. The cones that come from the virtual facets (VF) of the stone form the part of the space that is calculated as ETAS. Each virtual facet forms a 3D spatial cone that comes out of the stone and continues until it crosses a modeled light source surface (LSS), on which surface it is assumed that the light sources are placed. It is generally assumed that the LSS is a convex surface with the diamond in its center. The intersection of the cones with the LSS forms the ETAS spots. The size of a spot is determined by complex geometry factors such as the virtual facet, the pupil diameter, etc. The spots are characterized by the Fresnel intensity, the play ("latitude"), the size of a virtual facet, etc.
    Figure 1A shows an ETAS graph where the position of the cones shown is placed on a sphere for a round brilliant cut (RBC). The distribution of the spots on the sphere will only depend on the optical properties of the cut itself and not on the actual lighting conditions. The ETAS quantity is therefore a light-independent probabilistic quantity. The spots will contain white and colored spots. The colored spots have their origin in the dispersion in the diamond rays with a different color (blue, green, red) have a different refractive index, and thus follow a different path inside and outside the stone. On the basis of such an ETAS graph, a number of ETAS coefficients can be calculated to characterize the optical properties of the brick.
    A first ETAS coefficient, called ETAS Monochrome, can be calculated as the sum of the areas of all spots divided by the full sphere area squared. A larger total area of the spots on the ETAS graph results in greater probability for the brick to reflect the light source to the eye of an observer.
    A second ETAS coefficient, called ETAS Fire, only takes into account the colored spots on the sphere and sums up the surface of these colored spots. ETAS Fire is calculated, for example, as the square of this sum divided by the total sphere area. If a white light source were to be placed on the sphere around the stone in place of a colored spot on the ETAS graph, a monoscopic observer looking upwards would see a colored flash in the diamond caused by this light source.
    Figure 1B illustrates a further dynamic ETAS (DETAS) graph for an RBC showing the changing position of the spots on the sphere when the diamond is tilted two degrees. A tilting diamond "scans" a surrounding space and increases the probability of seeing the light source through the diamond during tilting. Depending on the light path in the stone, the position of the spots that are related to the virtual facets will change in different ways during tilting. The longer the spot caused by tilting, the greater the probability that the facet will send back a flash from a light source. The virtual facets that correspond to red lines on a DETAS graph are those that scan the longest paths with the highest angular spread while the stone is tilted. These indicate the greatest potential for the diamond to see a light source while tilting. Shorter blue lines or points have a much shorter path during tilting and green lines indicate an intermediate probability to reflect a light source.
    This third coefficient, called Dynamic ETAS or DETAS, uses the sum of all spot paths on the sphere while the stone is tilted. ETAS spots move over the sphere surface around the stone while the diamond is tilted. The area between the initial position of a monochromatic spot and its end position describes the dynamic ETAS spot. The "red line" will thus have a larger area between the initial position and the end position of a monochromatic stain. This therefore gives a higher DETAS value than "blue" or "green" lines. DETAS is calculated in the same way as ETAS quantities.
    Note that light reflection and ETAS quantities can be calculated as absolute values and / or as relative values. For the ETAS coefficients, the absolute values are a measure of the surface area on the sphere surface. The relative value is calculated as the absolute value for this quantity divided by the absolute value for the same quantity calculated in the same conditions for a Tolkowsky RBC. Relative values will be used in the discussion below of an embodiment of the method of the invention. This means that a value greater than 1 means that the relevant brick quantity is greater than for a Tolkowsky RBC. It will be understood by those skilled in the art that the method of the invention can also be implemented using absolute values or using another reference sharpening shape to calculate the relative values.
    The optical quantities can be calculated for the upright position of the brick and for a tilted brick. Different zones of a cut can also be taken into account - for example, quantities can be calculated for the entire crown of the cut, for the table alone, or for the crown without the table. Calculations can be made in a "mono" mode (cyclop mode) without taking into account the stereo vision effect or in a "stereo" mode (taking into account that the observer has two eyes). Furthermore, an "integral" mode may be provided that provides a mean quantity for "static, full crown" * "static, single table" * "tilt, full crown" * "tilt / table only".
    Simulation models
    For the method to work properly, it is necessary to use adequate simulation models for the lighting, the diamond and the observer. Psycho-physiological properties of human perception are preferably taken into account.
    The calculation of the ETAS Fire quantity preferably takes into account certain factors such as realistic modeling of a lighting source and the physical dimensions of a pupil.
    In the GIA model (described by Reinitz IM, Johnson ML, Hemphill TS, Gilbertson AM, Guerts RH, Green BD, Shigley JE Modeling the Appearance of the Round Brilliant Cut Diamond: An Analysis of Fire, and More About Brilliance. Gems & Gemology , Vol. XXXVII, Fall 2001, pp. 174-197.) A substantially parallel white light beam from an illumination source is used.
    The use of such an ideal model has the disadvantage that the probability of observing a green ray is the same as that of observing any other color, while in actual diamonds green rays are perceived much less commonly than blue and yellow rays.
    Furthermore, the GIA variable for dispersed color light return (DCLR) is almost independent of the dispersion and cannot accurately model the reflection of colored light.
    Observations have shown that a lighting source model with a convergence angle of the rays of about 6 degrees approximates the actual illumination and the model used in the method of the invention preferably takes this convergence angle into account, see http: //www.gemology. ru / cut / english / gradingl / 5.htm.
    The human eye has a pupil whose typical diameter is approximately 4 mm. This diameter can change depending on the lighting conditions. All the light that enters the eye passes through the pupil. If the eye is looking directly at a light source, the brightness of the source image that forms on the retina is independent of the distance between the eye and the source, provided that the size of this image is larger than the effective dimensions of a cluster of visual receptors in the retina. If there is an object such as a diamond between the eye and the source, its elemental prisms act as additional diaphragms. Consequently, the light passing through such a prism can produce a source image with a considerably reduced brightness. The operation of the elementary prisms depends on their size: a large prism hardly reduces image clarity, while a much smaller prism can produce a dimmed image that is not identifiable to the eye as a separate object. The dimensions of the elementary prisms depend on their quantity, the size of the stone and the location of its facets. Studying this problem makes it possible to determine the optimum combination of a light source and facet dimensions by numerical calculations. The relationship between the source, one of the facets, and the pupil of the eye is illustrated in Figure 2. If the light emitted by the source falls on a stone with few large facets, the stone produces some intense light beams; and if the light falls on a stone with many small facets, the stone produces many weak bundles. When the number of facets is large enough, the intensity of each of these bundles approaches zero.
    In an ETAS graph, the light flashes corresponding to different virtual facets can show more or less fire potential, see figure 3. A virtual facet that causes a white flash in the ETAS graph will result in a white flash in the brick if the light source is located in this position on the sphere surface around the stone, while the virtual facet that gives a wide colored flash on the ETAS image has a higher chance of producing a colored flash. If the light source is large enough to cover the full colored ETAS flash for covering this facet, then one would see a white color, but if the light source only partially covers the ETAS spot of the facet, the facet will have a colored flash deliver.
    To account for these effects in the calculation of the ETAS fire variable, the contribution of each spot for the value of a quantity can generally be expressed as: (squared area spot) x (spatial weight) x (additional weight)
    For each virtual facet, the position of red and violet monochromatic ETAS spots can be determined separately since the refractive index (RI) for red and violet light beams is different. It is possible to calculate the position of the ETAS spot on the bulb surface using the refractive index for red and for violet. The cross section of light spots from red to blue with a similar intensity produces a white zone, see figure 3A. If the light source is located in the white area of the spot, the flash in the stone will be colorless. The fire spots (which are supposed to be slightly colored) are the full colored spot surface minus the cross-section with red and violet spots (white zone). The "spatial weight" factor takes into account the location of the spot on an ETAS sphere surface, i.e. the spatial location of the ETAS spot.
    Furthermore, different parts of the space around the stone have different importance for the appearance of the diamond. Zones that are closer to the zenith have a greater chance of containing light sources than the lower part of the upper hemisphere. Generally, more spatial weight must be assigned to spots that are closer to the zenith. The standard way to assign spatial weight to a spot is to use a factor in the form of (cosine (angle_from_zenith)) n for the contribution of the spot, where the default value of n is, for example, 2. Spots that fall into the zone that is obstructed by a head are rejected from the summation of the quantity (and thus effectively have a spatial weight of zero).
    When the contributions for all ETAS spots are summed, each ETAS quantity can be calculated with various additional weight functions that increase or decrease the contribution of each spot for the total value. In an embodiment of the method below, an "intensity and size weighting" function is used, which implies that the contribution of each ETAS spot is multiplied by its intensity and the linear facets of the virtual facet that are representative of the size of the virtual facet. A virtual facet has both a surface and a length, with a larger or wider virtual facet as a whole or a longer virtual facet having a different effect as a potential light-emitting diaphragm.
    Influence of the size of the stone
    Figure 4 shows a larger number of spots that are the result of larger virtual facets in a 10 kt diamond (right) compared to a smaller 1 kt stone (left). The very small virtual facets in a smaller diamond that would not be able to be distinguished by the eye are preferably ignored by the model used to calculate the ETAS quantity, but a larger stone that has more distinctive flashes, must result in a larger ETAS value. To compare two cut shapes, it is therefore necessary to make an adjustment for size or weight.
    Furthermore, it is also possible to carry out a weighting that takes into account the different spreadings. The scatter parameter is a measure of "being solid" of a diamond crown surface compared to a standard diamond that is, for example, Tolkowsky. has proportions with a medium round thickness. The American Gern Society (AGS) uses for example:
    AGS spread (kt) = (D / 6.47) Λ3 - C
    AGS spread (%) = (1 - C * (6.47 / D) A3) * 100% C - weight of the (kt) D - diameter of the diamond (mm) 6.47 - diameter in mm of a diamond with a 1 kt weight and Tolkowsky ratios.
    A deeper diamond has a smaller spread, or a diamond with a thin roundist can have a larger spread or a larger surface area for a certain weight. In this case, a 1.00 kt RBC with the same raw ETAS value as a particular cushion cut of 1.20 ct with a 20% smaller spread can be weighted to result in the same adjusted ETAS value.
    "Dispersion Statistics" - the histogram of spatial fire spread
    The ETAS fire quantity takes into account the probability of the entire stone to display fire. However, to predict the spread of a high fire potential within a diamond, a spatial fire spread graph called "Dispersion Statistics Graph (Diamond in Ring)" is used. The graph makes it possible to verify the uniformity of the facets with a high fire spread potential. The "diamond in ring" is used as standard with only the light rays entering through the table and the crown facets taken into account.
    It is also possible to calculate a "chromatic dispersion" quantity. For each virtual facet, the "chromatic dispersion" can be calculated as: (dispersion angle) * (intensity) * (facet size)
    When a white light path leaves an optically dense medium, the colored rays split due to the different wavelength of the light which have a different refractive index in different transparent materials. The dispersion angle is an angle between the blue and green rays. The dispersion of light is also dependent on the angle of incidence and the angle of incidence, as in the example of dispersion created by a prism. "Chromatic dispersion" is a simplified quantity that is only used to verify the fire distribution. The "chromatic dispersion" quantity does not take into account the actual pupil size of the observer and therefore cannot estimate the total fire of the stone. An example of a "chromatic dispersion" chart is shown in Figure 11 which will be further discussed below.
    The chromatic dispersion size is the sum of the chromatic dispersion results for each of the virtual facets of the stone, which sum is normalized by the total crown area or the diameter of the stone when linear facet sizes are used in the summation instead of the surface. In other words, the chromatic dispersion quantity is the average dispersion * intensity.
    Note that the calculated "chromatic dispersion" values are not relative, since the 1 kt Tolkowsky RBD has no average per virtual facet of 1.00. The results can also be very different when the stone is tilted or viewed in stereo: the results for a round diamond increase for a large tilt range and vary depending on the stone orientation. The cushion average per virtual facet drops considerably during tilting.
    Chromatic dispersion is typically used to a limited extent during optimization as it does not take into account three characteristics of the ETAS quantities: the pupil size of an observer, the angle of light and the spatial weighting of the ETAS quantities on the sphere surface. Chromatic dispersion takes into account all dispersion angles, while ETAS fire only takes colored zones into account. Chromatic dispersion is therefore preferably not used for fire optimisations, since it will overestimate the fire for facets with very small dispersion angles. Chromatic dispersion is mainly used to determine the spread over the stone, and can be used, for example, to compare the table only with the crown alone.
    An embodiment of the method of the invention will now be described in detail for determining an optimized cushion cut for a diamond.
    Step 1. Analysis of multiple square cushion cut designs and the selection of optimized cut designs
    Fourteen types of cushion cut designs available on the market today were selected and analyzed by the following optical parameters defined above: - light reflection mono, hereinafter referred to as LRM ("light return mono"); - ETAS mono, hereinafter referred to as ETASM ("ETAS intensity and size weighted mono"); - ETAS fire mono, hereinafter referred to as ETASF ("ETAS Fire intensity and size weighted mono"); - ETAS dynamic (mono only), hereinafter referred to as ETASD ("ETAS Dynamic intensity and size weighted mono").
    For each type of cut design, a number of different crown angles ("crown angle"; Ca) and / or pavilion angles ("pavilion angle"; Pa) were selected. For the weight of the cushion stones it was assumed that this was approximately 1 kt.
    The simulation results for the optical quantities for the fourteen cut shapes are summarized in the table of Figure 5. Two types of cut shape designs showed the best optical performance: Cushion.P32C32B and CushionP. For each type of design, two cut designs were selected for further optimization. In the light reflection ETAS monochrome graph of Figure 6, these four cut shape designs are indicated by circles. The points represent the various analyzed cut designs. Since the Cushion.P32C32B model has limitations with regard to the parameter changes, this cut shape was not selected for further optimization and step 2 below goes further with the CushionP design. The CushionP design is illustrated in Figure 7 which shows a schematic top and bottom view, a photo-realistic image and the ETAS graph for this cut shape design.
    Step 2. Macro optimization of selected cushion cut designs by varying the main geometry parameters
    The selected CushionP design was optimized using four geometry parameters: - crown angle (Ca) - pavilion main facet angle (Pa) - pavilion depth (Pd) - star facets (Ib)
    Two maximums were found:
    pPa Tcä ΓΪ5 [~ Pd LRM ETASM ETASF ETASD
    1 38.6 10.2 8Ö 46.5 1,029 0.916 0.768 0.971 ~ 2 38.8 §78 8Ö 46.75 1.023 0.912 0.722 0.962
    Step 3. Micro-optimization by further varying less important geometry parameters
    The maxima found in step 2 were optimized by varying further minor geometry parameters in addition to the main geometry parameters. The following parameters were used: - crown height (Ch) - pavilion main facet corner (Pa) - lower facet depth (Io)
    Two maximums were found:
    TPa Tch Γϊο LRM ETASM: ETASF ETASD
    1 38.6 10.0 80.0 1,017 0.899 0.723 0.931 "2 35.0 14.0 75.0 0.827 1,025 1,256 1,131
    The first set of geometry proportions was almost the same as those found during the step 2 optimizations. The second set of geometry proportions was different and displayed a high ETAS fire value. Accordingly, the second set of proportions was selected as a test cut for polishing in step 4. This set of proportions was called "MSS Cushion 1".
    Step 4. Polishing the optimized cut shape design and comparison of the predicted and polished diamond "MSS Cushion 1" 0.55 kt was polished. A difference was found between the predicted and polished diamonds. In the polished stone, the cushion rondist shape was not correctly reproduced and, consequently, the azimuth of the main facets differed from those of the optimized cut shape design model. The size of the polished diamond was also smaller than 1 kt. For a comparison between the polished stone and the model, the simulated optical quantities were recalculated for a 0.55 kt diamond, both for the optimized symmetrical model and for the scanned model ( ie a model that matches the polished stone). The results are summarized in the table below and Figure 8 shows the ETAS graphs for the symmetrical model (left) and the scanned model (right).
    Symmetrical model scanned model
    Quantities 0.55 kt 0.55 kt LRM 0.84 0.75 ETASM 0.78 0.75 ETASF 0.93 0.89 ETASD 0.86 0.74
    The difference in quantities was mainly the result of azimuth variations of the rondist and main facets between the planned and the actually polished stone.
    Step 5. Analysis of the visual appearance of the actually polished diamond and control of negative effects
    The following considerations can be made when comparing diamonds. For loose diamonds, jewelers place the stones to be compared between two fingers on the back of their hand. The diamonds are seldom positioned perfectly upwards and often slip away. The resulting preference can vary when the test is repeated and body oils from the fingers can lead to dirt on the diamond, thereby spoiling the results. Furthermore, the lighting at a jewelry store is usually very bright, which can mislead a buyer. It is also difficult to compare the effect of fantasy cut shapes with known standards. The few existing standards for cut shape quality use different scales to compare different fancy cut shapes. Comparing the apparent size or surface of different stones in different stores is difficult for stones that are not round or square.
    To facilitate the comparison, the Applicant has developed a suitable box. This box is adapted for fixing the diamonds to be compared in an upwardly facing position with holders. Furthermore, the box can be provided with swinging means and with lighting means for creating different lighting conditions (for example, one environment to show brightness and another to show fire). The box also makes it possible to compare videos of fantasy cut shapes, in this case cushion cut diamonds, to a known standard: for example the "Tolkowsky AGS 0 Hearts and Arrow" round brilliant. The stones are mounted side by side as shown in Figure 9, and the rocking and lighting is the same for both. Furthermore, the box can be arranged to record high quality stereo videos of the stones to reproduce the human stereo vision. If the stones to be compared have about the same surface or the same carat weight, then real user confidence becomes possible.
    Figure 9 shows a screen shot of the video recorded through the box for a Tolkowsky round brilliant and the polished cushion cut shape. An analysis of the visual appearance of the diamond was also performed in a side-by-side comparison with a Tolkowsky AGS 0 RBC in different light conditions. This analysis can be done by different experts and users. Both video comparisons and direct comparisons therefore help to analyze the visual appearance.
    Analyzing the visual appearance resulted in the conclusion that the actually polished Cushionl cut has the following negative properties: - low light reflection (especially for the table). A clearly visible leak under the table; - low heat under the table; - long radiation path for the facets under the table so that the color may appear lower.
    Figure 10A shows a summary of the features of the Cushion 1 cut shape design.
    Step 6. Further optimisations, polishing and analysis of visual appearance
    Since the disadvantages of the "MSS Cushion 1" were clear and proved by a visual observation in step 5, it was decided to perform a further optimization step. The "MSS Cushion 1" set of geometry proportions was used as a starting point for a new optimization of the geometry parameters. This resulted in new geometry proportions and the corresponding cut shape design is called "MSS Cushion 2". The main features of the Cushion 2 cut design are illustrated in Figure 10B. "MSS Cushion 2" was polished and verified manually with the naked eye. The observers noted the following advantages / disadvantages for the cushion cut: - high light reflection (biggest difference with "MSS Cushion 1"); - no leak under the table; - high heat for the crown facets; - low heat under the table ("MSS Cushion 2" inherits the "MSS Cushion 1" negative characteristic, since both cushions have the same pattern).
    Figure 11 shows a chromatic dispersion chart for the "MSS Cushion 2" cut. It was observed that a diagonal cross is present under the table formed by the pavilion main facets. These facets lack fire as was proven and confirmed by a visual observation of the polished stone.
    Step 7. New simulation models for cushion optimisations The insights obtained from the optical quantities of the "MSS Cushion 1" and "MSS Cushion 2" cut forms a new standard with which cushions must comply. The conclusion is that better optimization results can be obtained if the diamond is divided into two zones (table and crown without table) where both zones must have high light reflection and fire. In other words, the simulation models used in step 1 must be adjusted to allow optimizations in different zones. In the present embodiment, the model was modified to use the following quantities: - light reflection mono; - ETAS mono; - ETAS fire; - ETAS dynamic (mono only); - light reflection mono - table only; - ETAS fire - table only.
    It was further concluded that a chromatic dispersion graph should be taken into account in the simulation models to avoid large matte clusters (without fire).
    Step 8. Design or pattern change based on the found defects of the polished brick "MSS Cushion 1" and "MSS Cushion 2" were based on the same CushionP DLL cut design. The lack of fire under the table is a permanent feature due to the pattern used in this cut design. A pattern change is therefore necessary to eliminate this negative characteristic. For the new optimization step there was an improvement in increasing the range in which the grinding shape parameters can change, see 2009_08_07_Cushion DLL in Figure 12 where the geometry pavilion parameters were changed considerably. Furthermore, a new cut shape design was added in which the main pavilion facets are split vertically, see Oct_16_2009_CushionSymmetry DLL in Figure 13. The next optimization step will then use "MSS Cushion 2" and two new DLL designs as the starting point.
    Step 9. Optimization of cushion with split facets The optimization of the cushion Oct_16_2009_CushionSymmetry DLL shown in Figure 13 by varying the primary and secondary geometry parameters resulted in a list of peaks. The grinding shape designs corresponding to the peaks are shown in Figure 13. The selection of the grinding shape design (s) to be polished was done by having experts and users vote on the basis of the simulated results for the grinding shape designs of Figure 13. "MSS Cushion 3" ( corresponding to number 2 in Figure 13) was selected based on the poll above.
    Following the "MSS Cushion 3", two other further optimized cut designs with the name "MSS Cushion 4" and "MSS Cushion 5" were polished. The optimizations of "MSS Cushion 3-5" resulted in a further change of the cushion pattern as shown in figure 14. Brilliantanting was also added to make the roundist thickness more uniform.
    Step 10. Analysis of the visual appearance of the polished cushions with split facets
    Polished "MSS Cushion 3", "MSS Cushion 4" and "MSS Cushion 5" were studied by different observers in different lighting conditions and compared in the box described above with a Tolkowsky RBC cut, see Figure 15 showing a Tolkowsky RBC, and the shows polished "MSS Cushion 3", "MSS Cushion 4" and "MSS Cushion 5" grinding shapes.
    During this observation it was established that the "MSS Cushion 4" cut has more total fire and also more fire under the table. The total observed brightness for "MSS Cushion 4" was higher than for the RBC. However, the observers found the "MSS Cushion 4" rondist form unusual: too round for the cushion, which is considered unattractive. "MSS Cushion 4" and "MSS Cushion 5" have a total fire and brightness value that is comparable to that of an RBC, but have less fire and brightness than "MSS Cushion 4". Consequently, the further optimization process focused on searching for a cushion cut shape with a more popular rondist shape (such as "MSS Cushion 3") but with high fire and brightness values.
    Step 11. Optimization of the cushion with split facets with quadratic round shape
    Further new cutting mold designs were added for the next cycle optimizations. First became the "MSS
    Cushion 6 ". This differs from the previously developed" MSS Cushions 3-5 "by a more square rondist shape, a larger table and less deep pavilion, but the cut shape continues to have the pattern design of" MSS Cushions 3-5 ". of the larger table and the new pavilion facet corners, "MSS Cushion 6" resulted in a very high ETAS fire value for the table zone.
    Step 12. Comparison of the parameters for the further optimized cushion grinding forms
    The primary optical quantities that were used directly in the further optimization process for the grinding mold designs "Cushion 1 to 6 are shown in Figure 16. There are three primary quantities: - light reflection mono full crown static - this is the light reflection of the stone in upward facing static position compared to a Tolkowsky RBC A light reflection of more than 1.00 means that the cushion is brighter than a Tolkowsky RBC Only Cushion 1 has a light reflection that is smaller than that of the Tolkowsky, Cushions 2-6 have a larger light reflection.
    - ETAS fire mono, full crown static - an ETAS quantity representing the global fire probability for the entire stone compared to a Tolkowsky RBC.
    - ETAS fire mono, table only, static - an ETAS quantity representing the fire probability for the path of the stone under the table.
    Cushions 1-3 have such fire probability that is smaller than that of the Tolkowsky. Cushions 4-5 have an ETAS fire for the table zone that is similar to that of a Tolkowsky RBC. Cushion 6 is characterized by a considerably higher ETAS fire.
    The ETAS quantities in the tables of Figures 16 et seq. Are calculated using two types of weightings: - a square weighting, the cushions in the calculations having the same area as a 1 kt Tolkowsky.
    - a weighting, where the quantities are calculated for 1 kt cushions and are weighted with 1 kt Tolkowsky.
    Cushion 6 is characterized by a high ETAS fire for the table zone and a high ETAS fire for the entire brick.
    After successive iterations based on the quantities and after matching the observations by observers, it is clear that the ETAS quantities are sensitive to the resolution of the eye - quantities calculated for 1 kt cushion and weighted on a 1 kt RBC will be different of the quantities calculated for a 10 kt cushion weighted on a 10 kt RBC. In the table of Figure 17, ETAS quantities are shown for a 10 kt cushion (normalized by a square weighting and by a weighting on an RBC). The weighted ETAS fire quantities for a 10 kt Cushion 6 (and some other cushions) are higher than for a 1 kt Cushion 6. This means that the fire of the Cushion 6 increases faster with the weight than is the case for the fire of a Cushion 6 RBC with the same dimensions. The progress of the quantities for Cushion 1 to Cushion 6 is clearly visible. A cushion with a high global fire value and a high fire value under the table was obtained during the continuous optimization process.
    Step 13. The optimization process for the cushion in stereo
    Obtained Cushions 1 to 6 show the possibility of creating a cushion cut with specific optical properties through a computer-aided optimization method. The Cushions 1 to 6 were mainly optimized for mono-optical quantities in a static position of the stone. The next step in the optimization process is to develop a cushion cut that is optimized for the highest possible fire when viewed in stereo mode (through two eyes) and when the stone is tilted.
    "MSS Cushion 7" was created by optimizing the cushion cut with stereo variants when the cut is tilted. To achieve the desired result, the pattern of Cushion 6 was changed by changing the azimuth of the crown main facets and by splitting the corner pavilion facets, see Figure 14. Cushion 7 ratios were found due to optimizations with stereo / tilt ETAS quantities. in an ETAS fire for a tilt of the stone for the entire crown and table that is higher than for a Tolkowsky RBC, see the table in figure 18. These stereo tilt ETAS fire quantities take into account the stereo vision of a person and the tilt of the stone by a real observer while examining the stone.
    Finally, "integral" quantities can be calculated as the average for the "static, full crown" * "static, table only" * "tilt, full crown" * "tilt, table only", see the table of Figure 19.
    Step 14. The best-functioning cut shapes are optimized for commercial production from rough diamonds
    After reaching a final optimal design, the commercial feasibility and viability can be considered. A range of ratios that achieve a desired result will allow an economical fitting of the desired shape into the available rough diamonds in a better way than a single set of ratios.
    There are different sets of facet relationships that can be varied such that a wider range of diamonds with the desired optical effect is possible. These parameters are programmed in rough diamond scanners and the most valuable outcome is predicted by the computer planning software.
    Figure 20 illustrates a simple example where only the crown height and pavilion depth were varied.
    The selected presentation concerns the dispersion in a ring. All the above-mentioned quantities can also be calculated for the example of parameter variations that were generated for the comparative example used in Figure 20 and these can be represented as in the 3D graph in Figure 21 where multiple peaks and ranges with good performance are present. This data can then be used to predict various parameters to ensure the most favorable weight for the planned polished stone for each piece of a rough diamond.
    Step 15. The difference between the actually polished diamond and the symmetrical model of the Cushion 4 example
    The Cushion 4 symmetrical cut shape design was used to cut an actual 1.02 kt diamond. The actually polished 1.02 kt stone was analyzed using the 3D scanned model of the polished stone. The actually polished stone shows a difference for the angles / azimuth for facets of the same type, due to the limited accuracy of the grinding devices. The technology of multi-step parameter control, however, helps to achieve very high accuracy for the cut. Figure 22 shows the difference in patterns between the symmetrical Cushion 4 model and the scanned model of the polished cut. It is observed that the rondist form of the symmetrical and actual cushions is well matched. Some facet connections on the crown and the pavilion are, however, somewhat offset. The accuracy for the main facets is better than 0.3 degrees. For the secondary facets, the difference of the angles between the symmetrical model and the actually polished diamond is greater and can be up to 1.5 degrees.
    The situation is similar for the azimuts: the reproducibility is better than 0.5 degrees for the main facets, and the difference can be up to 3 degrees for the secondary facets.
    The comparison of the main quantities for the symmetrical model and the actually polished Cushion 4 is shown in Figure 23. The light reflection quantity is almost the same. Main ETAS quantities (ETAS fire full crown static, ETAS monochrome full crown static and DETAS full crown static) are somewhat lower for the actually polished cushion. Only the "ETAS fire table only" quantity is considerably lower for the actually polished cushion.
    Finally, it is noted that as part of the pricing methodology, it is possible to estimate, for example, the efficient (beauty and / or the efficiency of a cut) using the ETAS quantities. In this way it can be compared how effectively the rough diamond material has been used to achieve optical effects (fire). Two types of weightings can be used: a square weighting, where the cushion ETAS quantities are weighed with Tolkowsky RBC quantities with the same area as the cushions, or a weighting, where cushion ETAS
    greats are weighted by Tolkowsky RBC greats with the same weight as the cushions.
    Figures 24, 25 and 26 show a first, second and third embodiment of a brick of the invention. The cut shape of these stones corresponds to the "Cushion 2" cut design defined above, the "Cushion 4, 5, 6" cut design (Cushions 4, 5 and 6 use the same pattern but have different geometry parameters) and the "Cushion 7" cut design . The cut comprises a pavilion with a pavilion height Ph and a collet C; a crown with a crown height Ch, and a table T with a table width Tw; and a round G between the pavilion and the crown.
    In the embodiment of figures 24 and 25, the crown comprises eight crown facets with a point adjacent to the roundist. The eight crown facets comprise four main crown facets 1 that are substantially symmetrically distributed around the roundist; and four corner crown facets 2, wherein each corner crown facet is located between two of the main crown facets. The crown preferably also comprises eight crown star facets 3 between the table and the crown facets. Furthermore, the crown comprises a number of further crown facets 8 with an edge adjacent to the roundist and located between a main crown facet and a corner crown facet 2. According to an optimized design, the main crown facets 1 describe an angle with respect to the plane of the roundist located between 31 and 36 degrees; and / or the angular crown facets 2 describe an angle with respect to the plane of the rondist that is between 28 and 36 degrees and / or the crown star facets 3 describe an angle with respect to the plane of the rondist that is between 18 and 26 degrees and / or the table width Tw is between 50 and 65% of the width W of the brick; and / or the crown height Ch is between 12 and 20% of the width W of the stone, preferably between 13 and 19%; and / or the pavilion height Ph is between 45 and 60% of the width W of the stone, preferably between 48 and 56%.
    For the embodiment of Figure 25, the pavilion comprises eight upper pavilion facets with a point adjacent to the rondist, which eight pavilion facets have four main pavilion facets 4 that are substantially symmetrically distributed around the rondist; and four corner pavilion facets 5. Each corner pavilion facet is located between two of the main crown facets. The pavilion further comprises a plurality of lower pavilion facets 6 adjacent to the collet. Furthermore, a number of additional facets 7 may be provided between the main pavilion facets 4 and the lower pavilion facets 6. A number of facets 9 may also be provided with an edge adjacent to the roundist and which are located next to a main or corner pavilion facet. According to a preferred cut shape, the main pavilion facets 4 describe an angle with respect to the plane of the rondist that is between 55 and 58 degrees; and / or the corner pavilion facets 5 describe an angle with respect to the plane of the rondist that is between 55 and 58 degrees; and / or the corner pavilion facets 5 describe an angle with respect to the plane of the rondist that is between 41 and 44 degrees; and / or the lower pavilion facets 5 describe an angle with respect to the plane of the roundist that is between 38 and 41 degrees.
    For the embodiment of Figure 24, the pavilion comprises eight upper pavilion facets with an edge adjacent to the roundist. The eight pavilion facets include four main pavilion facets 25 that are substantially symmetrically distributed around the rondist, and four corner pavilion facets 26, each corner pavilion facet being located between two main pavilion facets. The pavilion further comprises eight intermediate pavilion facets 28 with a point adjacent to the rondist, each intermediate pavilion facet being located between a main pavilion facet and a corner pavilion facet, and a plurality of lower pavilion facets 27 adjacent to the collet. According to a preferred embodiment, the main pavilion facets 25 describe an angle with respect to the plane of the rondist that is between 55 and 63 degrees; and / or the corner pavilion facets 26 describe an angle with respect to the plane of the rondist that is between 50 and 58 degrees; and / or the lower pavilion facets 27 describe an angle with respect to the plane of the roundist that is between 35 and 41 degrees; and / or the intermediate pavilion facets 28 describe an angle to the plane of the roundist that is between 38 and 44 degrees.
    In the embodiment of Figure 26, the crown comprises sixteen first crown facets with an edge adjacent to the rondist. The sixteen first crown facets comprise eight main crown facets 11 which are substantially symmetrically distributed around the rondist; and eight corner crown facets 12. Each corner has two corner crown facets located between two of the main crown facets. The crown further comprises eight second crown facets 14 with a point adjacent to the rondist and a point adjacent to the table, each second crown facet being located between a corner crown facet and a main crown facet. The crown preferably comprises eight crown star facets 13 between the table and the corner crown facets. According to a preferred embodiment, the main crown facets 11 describe an angle with respect to the plane of the rondist which is between 38 and 43 degrees; and / or the angular crown facets 12 describe an angle with respect to the plane of the rondist that is between 36 and 42 degrees; and / or the crown star facets 13 describe an angle with respect to the plane of the roundist that is between 25 and 30 degrees; and / or the second crown facets 14 describe an angle with respect to the plane of the rondist that is between 35 and 41 degrees. The pavilion preferably comprises sixteen upper pavilion facets 15 with an edge adjacent to the rondist, which sixteen upper pavilion facets are substantially symmetrically distributed around the rondist; eight corner pavilion facets 16 with a point adjacent to the rondist, which eight corner pavilion facets are substantially symmetrically distributed in the corners; and a plurality of lower pavilion facets 17 adjacent to the collet. The upper pavilion facets 15 preferably describe an angle to the plane of the roundist that is between 57 and 63 degrees; and / or the corner pavilion facets 16 describe an angle with respect to the plane of the rondist that is between 36 and 42 degrees; and / or the lower pavilion facets 17 describe an angle with respect to the plane of the roundist that is between 37 and 43 degrees; and / or the table width Tw is between 50 and 60% of the width W of the brick; and / or the crown height Ch is between 16 and 21% of the width W of the stone; and / or the pavilion height Ph is between 45 and 55% of the width W of the stone.
    The advantages of the grinding shapes of the embodiments of Figures 24-26 are illustrated in Figures 27-30 which show the different ETAS quantities for Cushions 1-7 compared to three commercially available square cushion grinding shapes. In particular for Cushion 6 (cut with the pattern of Figure 25) and Cushion 7 (Figure 26) it can be observed that the ETAS
    quantities are considerably higher in comparison with prior art stones.
    Although the principles of the invention have been set forth above for specific embodiments, those skilled in the art will appreciate that the description is only an example and not a limitation of the scope of protection defined by the appended claims.
    权利要求:
    Claims (44)
    [1]
    Method for determining a cut shape for a gemstone, comprising: - selecting a generic shape for the cut shape; - selecting a plurality of grinding shape designs from a group of grinding shape designs with the selected generic shape; - simulating a number of optical quantities for the plurality of grinding mold designs using simulation models with model coefficients; - selecting one or more grinding shape designs from the plurality of grinding shape designs based on the simulated optical quantities; - varying the geometry parameters for each selected cut shape design within a range, simulating a number of optical quantities for this range of geometry parameters, and determining an optimized cut shape design with optimized geometry parameters based on the simulated number of optical quantities for this range; - cutting and polishing the gem using the optimized cut designs with the optimized geometry parameters; - analyzing the visual appearance of the polished gemstone; - modifying or adjusting the simulation models and / or their model coefficients and / or the range for varying the geometry parameters and / or a grinding shape design of the multiple grinding shape designs, and / or adding one or more new grinding shape designs to the group of grinding mold designs, based on the visual appearance analysis.
    [2]
    The method of claim 1, wherein the generic form is one of the following generic forms: cushion, round, princess, emerald, asscher, oval, marquis, pear, radiant, heart.
    [3]
    A method according to any one of the preceding claims, wherein the generic shape is a cushion shape and wherein the geometry parameters include one or more of the following parameters: crown angle, pavilion main facet angle, pavilion depth, number of star facets, depth of bottom facets.
    [4]
    A method according to any one of the preceding claims, wherein the number of optical quantities comprises one or more of the following quantities: light reflection (brilliance), fire, glare (scintillation), life, a light-independent probabilistic optical quantity.
    [5]
    The method of claim 4, wherein the light-independent probabilistic optical quantity is an effective total angle-size quantity that uses light spots on a surface that result from a calculation of a portion of the space visible through the grinding shape design, which portion of the space is formed by a plurality of cones that converge in an observer's eye through the cut design, each cone comprising a light source.
    [6]
    The method of claim 5, wherein the effective total angle magnitude quantity comprises one or more of the following: a monochrome effective total angle magnitude that takes into account the light spots, a fire effective total angle magnitude that takes into account colored light spots, a dynamic effective total angle magnitude that takes into account changing the position of the light spots on the surface when the grinding shape design is tilted.
    [7]
    A method according to any one of the preceding claims, wherein the number of optical variables comprises a value determination quantity that takes into account one or more of the following effects: fish eye (nail), light leaks.
    [8]
    A method according to any one of the preceding claims, wherein the simulation models used to simulate the optical quantities are adapted to take into account the stereo vision effect and / or optical limitations of the human eye.
    [9]
    The method of any one of the preceding claims, wherein analyzing the visual appearance of the polished gemstone securing the gemstone in a container, measuring the gemstone in a static state and measuring the gemstone while it is being reciprocated moved under different light conditions to measure a set of optical quantities.
    [10]
    The method of claim 9, wherein the measured set of optical variables comprises one or more of the following variables: light reflection, fire and life.
    [11]
    A method according to any one of the preceding claims, wherein adjusting or changing a grinding shape design consists in adding or removing one or more facets of this grinding shape design.
    [12]
    A method according to any one of the preceding claims, wherein adding a new grinding mold design comprises adding a grinding mold design with a number of facets that is different from the number of facets of each of the plurality of grinding mold designs.
    [13]
    A method according to any one of the preceding claims, wherein adding a new grinding shape design consists of adding a new grinding shape design that differs therein from the optimized grinding shape design that has the shared facets.
    [14]
    A method according to any one of the preceding claims, wherein simulating a plurality of optical quantities for the plurality of grinding shape designs using model coefficients, simulating a first plurality of optical quantities for a first zone of each grinding shape design of the plurality of grinding shape designs and simulating a second number of optical quantities for a second zone thereof.
    [15]
    Method according to one of the preceding claims, characterized in that the steps of claim 1 are repeated a number of times for the same generic shape of the cut form.
    [16]
    A computer medium for storing a computer program with a programming code for determining a cut of a gemstone, which programming code comprises instructions for carrying out a number of steps of the method according to any one of the preceding claims, and in particular the following steps: selecting multiple cut shape designs with a selected generic shape; - simulating a number of optical quantities for the plurality of grinding mold designs using model coefficients; - selecting one or more grinding shape designs from the plurality of grinding shape designs based on the simulated optical quantities; - varying the geometry parameters for the selected one or more grinding shape designs within a range, simulating a number of optical quantities for this range of geometry parameters, and determining an optimized grinding shape design with optimized geometry parameters based on the simulated number of optical quantities for this range.
    [17]
    A stone that has been cut and polished in accordance with a cutting shape that has been determined using the method according to any one of the preceding claims, and which is made from a (semi) precious stone material, more particularly from natural or synthetic diamond, which stone has been cut and polished is in a square cushion shape with four corners, comprising: - a pavilion with a pavilion height (Ph) and a collet; - a crown with a crown height (Ch), which crown has a table with a table width (Tw); and - a roundist between the pavilion and the crown, characterized in that the crown comprises: - eight crown facets with a point adjacent to the roundist, said eight crown facets four main crown facets (1) substantially symmetrically distributed around the roundist; and comprises four corner crown facets (2), wherein each corner crown facet is located between two of the main crown facets; - eight crown star facets (3) between the table and the crown facets.
    [18]
    Stone according to claim 17, wherein the main crown facets (1) describe an angle with respect to the plane of the roundist that is between 30 and 38 degrees, preferably between 31 and 36 degrees.
    [19]
    A stone according to claim 17 or 18, wherein the angle crown facets (2) describe an angle with respect to the plane of the rondist that is between 27 and 38 degrees, preferably between 29 and 36 degrees.
    [20]
    A stone according to any one of claims 17-19, wherein the crown star facets (3) describe an angle with respect to the plane of the rondist that is between 17 and 27 degrees, preferably between 18 and 26 degrees.
    [21]
    A brick according to any one of claims 17-20, wherein the table width (Tw) is between 50 and 65% of the width (W) of the brick.
    [22]
    Stone according to one of claims 17 to 21, wherein the crown height (Ch) is between 12 and 20% of the width (W) of the stone, preferably between 13 and 19%.
    [23]
    A brick according to any one of claims 17-22, wherein the pavilion height (Ph) is between 45 and 60% of the width (W) of the brick, preferably between 48 and 56%.
    [24]
    A stone according to any one of claims 17-23, wherein the pavilion comprises: - eight upper pavilion facets with a point adjacent to the roundist, said eight pavilion facets four main pavilion facets (4) which are substantially symmetrically distributed around the roundist; and comprises four corner pavilion facets (5), each corner pavilion facet being located between two of the main crown facets; - several lower pavilion facets (6) adjacent to the collet.
    [25]
    The stone according to claim 24, wherein the main pavilion facets (4) describe an angle with respect to the plane of the rondist that is between 52 and 60 degrees, preferably between 55 and 58 degrees.
    [26]
    A stone according to any one of claims 24-25, wherein the corner pavilion facets (5) describe an angle with respect to the plane of the roundist that is between 39 and 46 degrees, preferably between 41 and 44 degrees.
    [27]
    Stone according to any of claims 24-26, wherein the lower pavilion facets (6) describe an angle with respect to the plane of the roundist that is between 36 and 43 degrees, preferably between 38 and 41 degrees.
    [28]
    A stone according to any one of claims 17-23, wherein the pavilion comprises: - eight upper pavilion facets with an edge adjacent to the rondist, said eight upper pavilion facets four main pavilion facets (25) substantially symmetrically distributed around the rondist, and four corner pavilion facets (26), wherein each corner pavilion facet is located between two main pavilion facets; - eight intermediate pavilion facets (28) with a point adjacent to the roundist, each intermediate pavilion facet being located between a main pavilion facet and a corner pavilion facet; - several lower pavilion facets (27) adjacent to the collet.
    [29]
    The stone of claim 28, wherein the main pavilion facets (25) describe an angle with respect to the plane of the rondist that is between 55 and 63 degrees.
    [30]
    The stone of any one of claims 28-29, wherein the corner pavilion facets (26) describe an angle with respect to the plane of the roundist that is between 50 and 58 degrees.
    [31]
    A stone according to any one of claims 28-30, wherein the lower pavilion facets (27) describe an angle with respect to the plane of the rondist that is between 35 and 41 degrees.
    [32]
    The stone of any one of claims 28 to 31, wherein the intermediate pavilion facets (28) describe an angle with respect to the plane of the roundist that is between 38 and 44 degrees.
    [33]
    33. Stone which has been cut and polished according to an abrasive shape which has been determined using the method according to any one of claims 1-16, and which is made from a (semi) precious stone material, more particularly from natural or synthetic diamond, which stone is cut and is polished in a square cushion shape with four corners, comprising: - a pavilion with a pavilion height (Ph) and a collet; - a crown with a crown height (Ch), which crown has a table with a table width (Tw); and - a circle between the pavilion and the crown, characterized in that the crown comprises: - sixteen first crown facets with an edge adjacent to the circle, said sixteen first crown facets eight main crown facets (11) substantially symmetrically distributed around the roundist; and comprises eight corner crown facets (12), wherein each corner is provided with two corner crown facets located between two of the main crown facets; - eight second crown facets (14) with a point adjacent to the circle and a point adjacent to the table, each second crown facet being located between a corner crown facet and a main crown facet; - eight crown star facets (13) between the table and the corner crown facets.
    [34]
    The stone of claim 33, wherein the main crown facets (11) describe an angle with respect to the plane of the rondist that is between 38 and 43 degrees.
    [35]
    The stone of any one of claims 33 to 34, wherein the angular crown facets (12) describe an angle with respect to the plane of the rondist that is between 36 and 42 degrees.
    [36]
    A stone according to any one of claims 33-35, wherein the crown star facets (13) describe an angle with respect to the plane of the rondist that is between 25 and 30 degrees.
    [37]
    The stone of any one of claims 33 to 36, wherein the second crown facets (14) describe an angle with respect to the plane of the rondist that is between 35 and 41 degrees.
    [38]
    The stone of any one of claims 33-37, wherein the pavilion comprises: - sixteen upper pavilion facets (15) that have an edge adjacent to the roundist and that are substantially symmetrically distributed around the roundist; - eight corner pavilion facets (16) with a point adjacent to the rondist, which corner pavilion facets are substantially symmetrically distributed in the corners; - a plurality of lower pavilion facets (17) adjacent to the collet.
    [39]
    The stone of claim 38, wherein the upper pavilion facets (15) describe an angle with respect to the plane of the rondist that is between 57 and 63 degrees.
    [40]
    The stone of any one of claims 38-39, wherein the corner pavilion facets (16) describe an angle with respect to the plane of the roundist that is between 36 and 42 degrees.
    [41]
    A stone according to any one of claims 38-40, wherein the lower pavilion facets (17) describe an angle with respect to the plane of the roundist that is between 37 and 43 degrees.
    [42]
    The brick of any one of claims 33 to 41, wherein the table width (Tw) is between 50 and 60% of the width (W) of the brick.
    [43]
    A brick according to any one of claims 33 to 42, wherein the crown height (Ch) is between 16 and 21% of the width (W) of the brick.
    [44]
    A brick according to any one of claims 33 to 43, wherein the pavilion height (Ph) is between 45 and 55% of the width (W) of the brick.
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    同族专利:
    公开号 | 公开日
    EP2713800A1|2014-04-09|
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    WO2006087702A1|2005-02-17|2006-08-24|Dialit Ltd.|Means and method of computer-aided manufacturing of polished gemstones from rough or semi processed gemstones|
    US7146827B2|2001-05-18|2006-12-12|Diamond Innovations, Llc|Mixed cut gemstone|
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    US7992410B2|2005-11-23|2011-08-09|Worldwide Diamond Trademarks Ltd.|Modified princess cut diamond having hearts and arrows pattern and method|
    US8639479B2|2007-11-27|2014-01-28|Ideal-Scope Pty. Ltd.|Method and system for improved optical modeling of gemstones|
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    US9265311B2|2013-12-23|2016-02-23|Hasenfeld-Stein, Inc.|Cushion cut gemstone with excellent optical brilliance|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    EP11167969|2011-05-27|
    EP11167969|2011-05-27|US13/997,687| US9311435B2|2011-05-27|2012-03-20|Method for determining a cut for a gemstone|
    PCT/IB2012/051323| WO2012164410A1|2011-05-27|2012-03-20|Method for determining a cut for a gemstone|
    EP12711283.7A| EP2713800B1|2011-05-27|2012-03-20|Method for determining a cut for a gemstone|
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