FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
5 AND
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
10

SYSTEM AND METHOD FOR MARKING GEMSTONES
15
SAHAJANAND TECHNOLOGIES PRIVATE LIMITED, a company
incorporated under applicable laws of India having its registered office at A1, Sahajanand Estate, Vakhariawadi, Nr. Dabholi Char Rasta, Surat – 395004,
GJ, INDIA
20
The following specification describes the invention
2
DESCRIPTION FIELD OF THE INVENTION
[0001] The following invention is related to marking gemstones, specifically
diamonds.
5 BACKGROUND OF THE INVENTION
[0002] Gemstones are rare pieces of precious or semi-precious stones, which have
been used since generations in jewellery or other adornments. These gemstones
undergo multiple processing techniques such as cutting, polishing, and faceting to
achieve their ornamental form. However, to prevent fraud and provide confidence
10 to buyers, gemstones are marked for identification using serial numbers, logos, or
certification codes.
[0003] Traditional methods of marking a gemstone involves laser marking directly
on the gemstone's surface, which generates contrast through ablation or
discoloration. Such process result in damage to the surface of the gemstone, thereby
15 degrading it’s quality. Even though the marking by the existing methods is often
placed in less prominent areas, but still such degradation is not expected in premium
gemstones.
[0004] Thus, there is a need of a system/method of identification
marking/inscribing gemstones with marking information which preserves the
20 gemstone's visual integrity while ensuring that the mark is legible and verifiable
under standard viewing conditions and/or with appropriate magnification and
illumination condition.
OBJECT OF THE INVENTION
25 [0005] It is the object of the present specification to provide a system and a method
of marking a gemstone which preserves the gemstone's visual integrity
[0006] Yet another object of the specification to provide a system and a method of
marking a gemstone of marking a gemstone while ensuring that the mark is legible
and verifiable under standard viewing condition and/or with appropriate
30 magnification and illumination condition.
3
SUMMARY OF THE INVENTION
[0007] The following presents a simplified summary of the disclosure in order to
provide a basic understanding to the reader. This summary is not an extensive
overview of the disclosure, and it does not identify key/critical elements of the
5 invention or delineate the scope of the invention. Its sole purpose is to present some
concepts disclosed herein in a simplified form as a prelude to the more detailed
description that is presented later.
[0001] The disclosure seeks to provide a method and system for marking a
gemstone with identification information. The disclosure provides a solution to
10 accurately mark/inscribe the gemstone with minimal quality degradation. Thus, the
present disclosure aims at bridging the existing gap in the present technology.
[0008] In an embodiment, the disclosed system includes an imaging unit that
captures a plurality of images of the gemstone. The disclosed system further
includes a processing unit and a marking unit. The processing unit is operable to
15 generate accurate three-dimensional (3D) model of the gemstone based on the
captured images. The processing unit further acquires input data, projects the input
data on the 3D model and divides the input data into a plurality of X-Y coordinates
of a virtual grid.
[0009] The processing unit then project a ray perpendicular to the table facet into
20 the gemstone's interior for a X-Y coordinate of the plurality of X-Y coordinates,
and identifies an exit point of a plurality of exit points of the ray on the nonsignificant sides of the gemstone corresponding to each X-Y coordinate of the
plurality of X-Y coordinates.
[0010] The marking unit is operable to operate a laser assembly to move a laser
25 beam on each identified exit point of the plurality of exit points and engrave a
microscopic dot on each identified exit points.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] These features and advantages of the present disclosure may be appreciated
30 by reviewing the following description of the present disclosure, along with the
accompanying figures wherein like reference numerals refer to like parts. Various
4
embodiments will hereinafter be described in accordance with the appended
drawings, which are provided to illustrate, not limit, the scope, wherein similar
designations denote similar elements, and in which:
5 [0012] Figure 1 depicts various components of a system (100) for marking the
gemstones, in accordance with an embodiment of the present disclosure.
[0013] Figure 2 depicts various components of a gemstone marking machine (101)
for marking the gemstones, in accordance with an embodiment of the present
disclosure.
10 [0014] Figure 3a-c depicts various stages of diamond marking by the system (100)
in accordance to an exemplary embodiment.
[0015] Figure 4 depicts a method (400) of marking the gemstone, in accordance
with an embodiment of the present disclosure.
[0016] The accompanying drawings illustrate the embodiments of systems,
15 methods, and other aspects of the disclosure. Any person with ordinary skills in the
art will appreciate that the illustrated element boundaries (e.g., boxes, groups of
boxes, or other shapes) in the figures represent an example of the boundaries. In
some examples, one element may be designed as multiple elements, or multiple
elements may be designed as one element. In some examples, an element shown as
20 an internal component of one element may be implemented as an external
component in another and vice versa. Furthermore, the elements may not be drawn
to scale.
DESCRIPTION OF THE INVENTION
25
[0017] The present disclosure is best understood with reference to the detailed
figures and description set forth herein. Various embodiments have been discussed
with reference to the figures. However, those skilled in the art will readily
appreciate that the detailed descriptions provided herein with respect to the figures
30 are merely for explanatory purposes, as the methods and systems may extend
beyond the described embodiments. As used in the description herein and
5
throughout the claims that follow, the meaning of “a,” “an,” and “the” includes
plural reference unless the context dictates otherwise. Also, as used in the
description herein, the meaning of “in” includes “in” and “on” unless the context
dictates otherwise.
5
[0018] References to “one embodiment,” “at least one embodiment,” “an
embodiment,” “one example,” “an example,” “for example,” and so on indicate that
the embodiment(s) or example(s) may include a particular feature, structure,
characteristic, property, element, or limitation but that not every embodiment or
10 example necessarily includes that particular feature, structure, characteristic,
property, element, or limitation. Further, repeated use of the phrase “in an
embodiment” does not necessarily refer to the same embodiment.
[0019] Methods of the present specification may be implemented by performing or
15 completing manually, automatically, or a combination thereof, selected steps or
tasks. The term “method” refers to manners, means, techniques and procedures for
accomplishing a given task including, but not limited to, those manners, means,
techniques, and procedures either known to, or readily developed from known
manners, means, techniques and procedures by practitioners of the art to which the
20 invention belongs. The descriptions, examples, methods, and materials presented in
the claims and the specification are not to be construed as limiting but rather as
illustrative only. Those skilled in the art will envision many other possible
variations within the scope of the technology described herein.
25 [0020] Figure 1 illustrates the gemstone marking system 100 in accordance with an
embodiment of the present disclosure. With respect to Fig. 1, the gemstone
processing machine (100) includes a gemstone holder (not shown), a gemstone
marking machine (101) and a database (102). In an embodiment, the gemstone
marking machine (101) and the database 102 are communicable to each other via a
30 network 103.
6
[0021] The network (103) may be any kind of public/secured network, or a
combination of different networks. In an embodiment, the network (103) may be
the Internet, a Wi-Fi network, a local area network (LAN) network, a wide area
5 network (WAN) network. The network (103) can also be wired, such as an Ethernet
network, or a cellular network including EDGE, 3G and 4G wireless cellular
systems.
[0022] The database (102) can include any storage medium known in the art
10 including, for example, volatile memory, such as static random-access memory
(SRAM) and dynamic random-access memory (DRAM), and/or non-volatile
memory, such as read only memory (ROM), erasable programmable rom, flash
memories, hard disks, magnetic tapes, and optical disks.
15 [0023] In operation, the gemstone marking machine (101) acquires gemstone
information for each gemstone of a plurality of gemstones. In an embodiment, the
gemstone information of a gemstone of the plurality of gemstones includes at least
refractive index information of the gemstone.
20 [0024] The gemstone marking machine (101) selects the refractive index from a
database based on a type of the gemstone.
[0025] In an embodiment, the refractive index information may be pre-fixed,
selectable from the databased based on type of the gemstone or can be entered by
25 an operator. The selected gemstone is mounted on the holder. In an embodiment,
the holder is placed on a rotating table base. The selected gemstone may be
automatically mounted by the gemstone marking machine (101) or it can be
manually placed by the operator.
30 [0026] The gemstone marking machine (101) captures one or more images of the
gemstone. In an embodiment, the gemstone marking machine (101) captures the
7
one or more images of the gemstone using backlight and 360-degree telecentric
photography. The gemstone marking machine (101) is further operable to generate
a three dimensional (3D) model of the gemstone using the captured one or more
images. The one or more captured images corresponds to images of the gemstone
5 that includes one or more of a top facet of the gemstone, a crown of the gemstone,
a girdle of the gemstone, and bottom facets of the gemstone. Thus, the gemstone
marking machine (101) is able to capture precise external dimensions and facet
geometry of the gemstone based on the captures one or more images. This capability
of the gemstone marking machine (101) allows applicability to various gemstones
10 (e.g., diamonds, sapphires) with adjustable refractive indices and cut styles.
[0027] In an embodiment, the operator of the gemstone marking machine (101)
inputs the marking data. In an embodiment, the input data can be pre-stored in the
database 102. In an embodiment, the gemstone marking machine (101) acquires the
15 input data from the database (102). In an embodiment, the input data is virtually
projected onto the table side of the gemstone's 3D model. This virtual projection
simulates how the input data would appear if directly applied to the table facet,
serving as a reference for the dispersion. The projected input data is digitally broken
down into a high-resolution dot matrix. In an embodiment, each "dot" represents a
20 pixel-like element of the marking, with resolution adjusted based on the gemstone's
size and a complexity of the input data.
[0028] Further, a virtual grid is visible on a display associated with the gemstone
marking machine (101). The displayed virtual grid includes a horizontal X-axis,
25 and a vertical Y-axis. In an embodiment, the input data is projected using the virtual
grid, onto the table side of the gemstone's 3D model. This virtual projection
simulates how the input data would appear if directly applied to the table facet,
serving as a reference for the dispersion. The projected input data is further divided
i.e. digitally broken down into a high-resolution dot matrix in form of a plurality of
30 the X-Y coordinates of a virtual grid. In an embodiment, each coordinate of the a
plurality of the X-Y coordinates represents a pixel-like element of the input data,
8
with resolution adjusted based on the gemstone's size and a complexity of the input
data.
[0029] Further, for each coordinate in the virtual grid on the table side of the
5 gemstone’s 3D model, a ray is computationally projected perpendicular to the table
facet into the gemstone's interior. This simulates light paths entering the gemstone
from the viewing direction.
[0030] In an embodiment, each projected ray is traced through the gemstone's
10 volume, accounting for its material-specific refractive index (e.g., ~2.42 for
diamond) based on the ray tracing algorithms. The gemstone marking machine
(101) is operable to calculate refraction, reflection, and path deviation at internal
facet interfaces based on the tracing of the projected ray determining the exit point
on a non-significant side of the gemstone (typically the pavilion facets of the
15 gemstone).
[0031] Furthermore based on the tracing, the gemstone marking machine (101) is
operable to identify an exit point of the projected ray on non-significant sides of the
gemstone. The gemstone marking machine (101) is further operable to identify a
20 plurality of the exit points such that each exit point corresponding to each X-Y
coordinate of the plurality of X-Y coordinates.
[0032] The gemstone marking machine (101) operates a laser assembly to engrave
a microscopic dot on each identified exit points. In an embodiment, the laser
25 corresponds to a focused femtosecond pulse laser. The microscopic dots correspond
to subtle ablation or subsurface modifications that generate contrast without
significant material removal or cracking. The microscopic dots are sized to be
nearly invisible to the naked eye (e.g., <10 microns) and distributed across multiple
facets to avoid clustering.
30
9
[0033] When the gemstone is viewed from the table side under magnification or
appropriate illumination, the microscopic dots that corresponds to each exit point
on the non-significant side of the gemstone, creates a "virtual" marking that is
readable without direct surface alteration on the dominant facets.
5
[0034] Hence, the input data is translated in form of exit points of the laser from
the gemstone, and thereby the input data appears as the contrast generating marking
on the non-significant side of the gemstone.
10 [0035] Figure 2 depicts the various components of the gemstone marking machine
(101) in accordance to an embodiment of the present disclosure. The gemstone
marking machine (101) includes an imaging unit (103), a processing unit (104), and
a marking unit (105).
15 [0036] The imaging unit (103) is operable to capture the plurality of images of the
gemstone placed on the gemstone holder. In an embodiment, the imaging unit (103)
may utilize a back light or 360-degree telecentric photography to capture the
plurality of images of the gemstone. The imaging unit (103) may be, but is not
limited to, a camera. In an embodiment, the imaging unit (103) captures the plurality
20 of images in multiple directions that corresponds to one or more of a top facet of
the gemstone, a crown of the gemstone, a girdle of the gemstone, and bottom facets
of the gemstone. The gemstone holder may be rotated by the gemstone marking
machine (100) such that the imaging unit (103) can capture the images of multiple
facets of the gemstone.
25
[0037] The processing unit (104) is operable to receive the plurality of images of
the gemstone and generate a 3D model of the gemstone based on the plurality of
images. In an embodiment, the processing unit (104) can be implemented as a
microcontroller, a microcomputer, a core processor, or may be any other type of
30 processor which is recognizable by a person skilled in art. In an embodiment, the
processing unit (104) may be a low-power microcontroller (e.g., Arduino Nano).
10
Further in an embodiment, the processing unit (104) may be implementable on one
of an Field Programmable Gate Array (FPGA), a Programmable Logic Device
(PLD), or may be implementable using discrete logic circuits, as one of ordinary
skill in the art would recognize. Further, the processing unit (104) can be
5 implemented as a unit by combining multiple processors that works in parallel to
execute the operations of the processing unit (104).
[0038] In an embodiment, the processing unit (104) is operable to display the
projected 3D model of the gemstone on the virtual grid, on the display associated
10 with the gemstone marking machine (101).
[0039] In an embodiment, the processing unit (104) is further operable to receive
the input data through an input unit (not shown) included in the gemstone marking
machine (101). Further the processing unit (104) is operable to project the input
15 data onto the table side of the displayed gemstone's 3D model. The processing unit
(104) is operable to divide the input data into a plurality of X-Y coordinates of the
virtual grid. Each coordinate of the plurality of the X-Y coordinates represents a
pixel-like element of the input data, with resolution adjusted based on the
gemstone's size and a complexity of the input data. The processing unit (104)
20 projects a ray perpendicular to the table facet into the gemstone's interior for each
coordinate of the plurality of the X-Y coordinates. The processing unit (104) trace
each ray through the gemstone's volume based on the ray tracing algorithms.
[0040] The processing unit (104) identifies an exit point of the plurality of exit
25 points of the rays based on the traced ray. In an embodiment, each exit point
corresponds to each X-Y coordinate of the plurality of X-Y coordinates.
[0041] The processing unit (104) instructs the marking unit (105) to operate the
laser assembly to engrave a microscopic dot on each identified exit points. The
30 microscopic dots are sized to be nearly invisible to the naked eye (e.g., <10 microns)
and distributed across multiple facets to avoid clustering.
11
[0042] The microscopic dots that correspond to each exit point on the nonsignificant side of the gemstone, creates a "virtual" marking that is readable without
direct surface alteration on the dominant facets. As the input data is marked using
the microscopic dots, thus this technique provides high level of security as altering
5 the microscopic dots would require precise knowledge of the ray tracing model.
[0043] Figures 3A, 3B, and 3C show various images of the gemstone that
corresponds to various stages of marking of the gemstone as executed by the
gemstone marking machine (101). The red markings 302 shown in Figures 3A, 3B,
10 and 3C corresponds to the plurality of exit points identified based on the input data.
For example, the input data is “A” that needs to be marked on the gemstone. FIG.
3A shows the exit points corresponding to “A” from the non-significant side of the
gemstone. FIG. 3B shows the exit points corresponding to “A” from the lateral side
of the gemstone. FIG. 3C shows the image of the non-significant side of the
15 gemstone with marked input data.
[0044] The method performed by the gemstone marking machine 101 may be
explained with respect to Fig. 4. Fig. 4 illustrates a method (400) of marking the
gemstone. The method (400) includes step (401), step (402), step (403), step (404),
20 step (405), step (406), step (407), and step (408).
[0045] The operation of marking the gemstone initiates with the step (401). At the
step (401), a plurality of images of the gemstone placed on the holder are captured
by the imaging unit (103) using backlight and 360-degree telecentric photography.
25 At the step (402), a 3D model of the gemstone is generated by the processing unit
(104) based on the images captures at the step (301).
[0046] The method now moves to the step (403). At the step (403), an input data is
acquired by the processing unit (104). In an embodiment, the input data may be
30 provided by the operator associated with the gemstone marking machine (101). At
12
the step (404), the acquired input data is projected on the table side of the gemstone's
3D model.
[0047] At the step (405), the projected input data is divided into the plurality of X5 Y coordinates of the virtual grid. In an embodiment, the virtual grid is being
displayed on the display associated with the gemstone marking machine (101). In
an embodiment, the virtual grid includes X-Y axes, which are perpendicular to each
other. Any point on the grid can be represented by a X-coordinate and a Ycoordinate. In an embodiment, each coordinate of the a plurality of the X-Y
10 coordinates represents a pixel-like element of the input data, with resolution
adjusted based on the gemstone's size and a complexity of the input data.
[0048] In the step (406), for each coordinate in the virtual grid on the table side of
the gemstone’s 3D model, a ray is computationally projected perpendicular to the
15 table facet into the gemstone's interior by using ray tracing algorithms.
[0049] In the step (407), a plurality of exit points are identified on the nonsignificant side of the gemstone based on tracing of the projected rays. In an
embodiment, each exit point may correspond to each X-Y coordinate of the
20 plurality of X-Y coordinate. Thus, referring to the example provided on FIG. 3A,
the red markings correspond to the plurality of exit points.
[0050] The method now moves to step (408). In the step (408), the laser is moved
on each of the identified plurality of exit point and a microscopic dot is engraved
25 on each exit point.
[0051] It may be noted that the steps 401, 402, 403, 404, 405, 406, 407, and 408
respectively, are only preferable steps and other alternatives may be provided where
few more steps are added, few steps are removed, or few steps are provided in a
30 different sequence without departing from the scope of the claims herein.
13
[0052] Thus, the disclosed method, as described above, results creating a "virtual"
marking that is readable without direct surface alteration on the dominant facets.
[0053] While the preferred embodiments of the present disclosure have been
5 described herein above, it should be understood that various changes, adaptations,
and modifications may be made therein without departing from the spirit of the
invention and the scope of the appended claims. It will be obvious to a person
skilled in the art that the present invention may be embodied in other specific forms
without departing from its spirit or essential characteristics. The described
10 embodiments are to be considered in all respects only as illustrative and not
restrictive.
[0054] Features described as separate implementations may be implemented, in
combination, in a single implementation, while features described as a single
15 implementation may be implemented in multiple implementations, separately, or in
any suitable sub-combination. Operations or processes or methods described and
claimed in a particular order should not be understood as requiring that the
particular order, nor that all illustrated operations must be performed (some
operations can be optional). As appropriate, multitasking or parallel-processing (or
20 a combination of multitasking and parallel-processing) can be performed.
[0055] No language in the specification should be construed as indicating any nonclaimed element as essential to the practice of the invention.
25 [0056] All device elements and units described herein the present disclosure could
be implemented in the software or hardware elements or any kind of combination
thereof. All steps which are performed by the various entities described in the above
describes disclosure can be implemented in corresponding software or hardware
elements, or a combination thereof.

[0057] It will be apparent to those skilled in the art that various modifications and
variations can be made to the present specification without departing from the scope
of the invention. There is no intention to limit the invention to the specific form or
forms enclosed. On the contrary, the intention is to cover all modifications,
5 alternative constructions, and equivalents falling within the scope of the invention,
as defined in the appended claims. Thus, it is intended that the present specification
covers the modifications and variations of this invention, provided they are within
the scope of the appended claims and their equivalents.

CLAIMS
I/We claim:

1. A system (101) for marking a gemstone, the system (101) comprising:
a) an imaging unit (103) configured to capture a plurality of images of the
gemstone; and
b) a processing unit (104) configured to:
generate accurate three-dimensional (3D) model of the gemstone
based on the captured images;
acquire input data;
divide the input data into a plurality of X-Y coordinates of a virtual
grid; and
identify a plurality of exit points on the non-significant sides of the
gemstone corresponding to each X-Y coordinate of the plurality of X-Y
coordinates;
c) a marking unit (105) configured to:
operate a laser assembly to move the laser beam on each identified
exit point of the plurality of exit points and engrave a microscopic dot on
each identified exit points.
2. The system (101) as claimed in claim 1, wherein
a refractive index of the gemstone is one of pre-fixed, or set based on an
operator input, or the refractive index is selected based on the gemstone type.
3. The system (101) as claimed in claim 1, wherein the input data is provided by an
operator.
4. The system (101) as claimed in claim 1, wherein the gemstone is placed on a
holder.
5. The system (101) as claimed in claim 1, wherein the processing unit (104) is
further configured to project a ray, perpendicular to the table facet, into the
gemstone's interior for a X-Y coordinate of the plurality of X-Y coordinates.
6. The system (101) as claimed in claim 5, wherein the processing unit (104) is
further configured to identify an exit point of the plurality of exit points,
corresponding to the X-Y coordinate, based on tracing of the projected ray using
Ray Tracing algorithms.
7. A method (400) of marking a gemstone, the method (400) comprising:
capturing a plurality of images of the gemstone;
generating a three-dimensional (3D) model of the gemstone based on the
captured images;
acquiring an input data;
dividing the input data into a plurality of X-Y coordinates of a virtual grid;
identifying a plurality of exit points on the non-significant sides of the
gemstone corresponding to each X-Y coordinate of the plurality of X-Y
coordinates; and
moving the laser beam on each identified exit point of the plurality of exit
points to engrave a microscopic dot on each identified exit points.
8. The method (400) as claimed in claim 5, wherein
a refractive index of the gemstone is one of pre-fixed, or set based on an
operator input, or the refractive index is selected based on the gemstone type.
9. The method (400) as claimed in claim 5, wherein the input data is provided by
an operator.