U.S. patent application number 11/029191 was filed with the patent office on 2006-07-06 for method for engraving irreproducible pattern on the surface of a diamond.
This patent application is currently assigned to Academia Sinica. Invention is credited to Yuh-Lin Wang.
Application Number | 20060144821 11/029191 |
Document ID | / |
Family ID | 36639175 |
Filed Date | 2006-07-06 |
United States Patent
Application |
20060144821 |
Kind Code |
A1 |
Wang; Yuh-Lin |
July 6, 2006 |
Method for engraving irreproducible pattern on the surface of a
diamond
Abstract
The present invention provides a method for engraving desired
irreproducible patterns on the surface of gemstones including
diamond by the use of an energetic ion beam. The pattern has a
characteristic topological texture, which is irreproducible even
using the same ion beam to engrave onto the same location of the
same diamond.
Inventors: |
Wang; Yuh-Lin; (Taipei,
TW) |
Correspondence
Address: |
COHEN, PONTANI, LIEBERMAN & PAVANE
551 FIFTH AVENUE
SUITE 1210
NEW YORK
NY
10176
US
|
Assignee: |
Academia Sinica
|
Family ID: |
36639175 |
Appl. No.: |
11/029191 |
Filed: |
January 4, 2005 |
Current U.S.
Class: |
216/66 |
Current CPC
Class: |
H01J 2237/31737
20130101; A44C 27/00 20130101; A44C 17/005 20130101 |
Class at
Publication: |
216/066 |
International
Class: |
C23F 1/00 20060101
C23F001/00 |
Claims
1. A method for engraving an irreproducible pattern on the surface
of a diamond, comprising the step of: exposing an energetic ion
beam onto the surface of the diamond at an angle from the normal of
the surface of about 45.degree.-85.degree..
2. The method according to claim 1 wherein the angle is of about
50.degree.-70.degree..
3. The method according to claim 1 wherein the angle is of about
55.degree.-65.degree..
4. The method according to claim 1 wherein the angle is of about
60.degree..
5. The method according to claim 1 further comprising the step of
engraving a second pattern on the surface of the diamond.
6. A method according to claim 5 wherein the size of the entire
said second pattern can be as large as the area of the surface of
the diamond.
7. The method according to claim 5 wherein said second pattern is
at least one selected from the group consisting of a photograph,
printed character, drawing, and signature.
8. The method according to claim 1 wherein said energetic ion beam
is a focused ion beam.
9. The method according to claim 8 wherein the diameter of said
focused ion beam is about 5 nm.
10. A method for engraving an irreproducible pattern on the surface
of a diamond, comprising the steps of: positioning a mask between
an output of an ion beam and the surface of the diamond; and
exposing the ion beam on the exposed area of the mask at an angle
from the normal of the surface of about 45.degree.-85.degree..
11. The method according to claim 10 wherein the angle is of about
50.degree.-70.degree..
12. The method according to claim 10 wherein the angle is of about
55.degree.-65.degree..
13. The method according to claim 10 wherein the angle is of about
60.degree..
14. The method according to claim 10 wherein the step of
positioning a mask comprises the steps of: covering the surface of
the diamond with a resist layer; and removing selected portion of
the resist layer to expose an area to said energetic ion beam.
15. The method according to claim 10 wherein said energetic ion
beam is a broad ion beam.
16. The method according to claim 15 wherein said broad ion beam is
Ar+.
17. A diamond having a surface on which is a pattern has been
applied using the method comprising the step of: exposing an
energetic ion beam onto the surface of the diamond at a angle from
the normal of the surface of about 45.degree.-85.degree..
18. A method of authenticating an object comprising permanently
attaching to the object a diamond according to claim 17.
Description
FIELD OF THE INVENTION
[0001] The present invention is in the field of ion beam marking on
gemstones, and more specifically on diamonds.
BACKGROUND OF THE INVENTION
[0002] Historically, marking of a diamond was not considered
practical because it is the hardest material on Earth. Thanks to
the invention of modem laser and ion beams, it is now possible to
conduct lithography on the surface of diamond using these energetic
beams. The mark created on a diamond can be reduced to such a small
scale that it is invisible to the naked eye or under the
observation of a loupe with a ten times magnification; and it does
not affect the clarity or the color grade of the diamond. The mark
can also be made so large that it is visible to the naked eye, and
certain desired special visual effects can be produced by the
lithographic processes to enhance the appeal of a diamond. Such a
mark on a diamond can be, for instance, the logo of the company
responsible for the cutting, polishing, and setting of the diamond.
It can also be the miniaturized signature or even photograph of the
jeweler or artist. In principle, the marks created by either laser
or ion beam can be used as a form of identification.
[0003] Various energetic ion beam marking techniques are known to
be employed to produce patterns on a gemstone surface. For example,
see U.S. Pat. Nos. 5,773,116 and 6,391,215. U.S. Pat. No. 5,773,116
discloses an ultrahigh vacuum focused ion beam micromilling
apparatus and process. Additionally, a durable data storage medium
using the micromilling process is disclosed, wherein the durable
data storage medium is capable of storing, e.g., digital or
alphanumeric characters as well as graphical shapes or characters.
U.S. Pat. No. 6,391,215 discloses an information mark invisible to
the naked eye which is applied to the polished facet of a diamond
gemstone by coating the diamond gemstone surface with an
electrically conductive layer so as to prevent the diamond from
becoming charged, forming the mark with a focused ion beam, and
cleaning the diamond surface with a powerful oxidizing agent to
reveal a mark having an appropriate depth. The information mark
does not detrimentally affect the clarity or color grade of the
diamond.
[0004] However, these marking methods are not sufficient for
authentication in the sense that an identification mark can be
easily forged.
SUMMARY OF THE INVENTION
[0005] It is the main purpose of this invention to address the
above issue by introducing ion-beam-based lithographic processes
that can create irreproducible patterns with a characteristic
texture on the nanometer scale. The pattern not only can be used
for proving the authenticity of the jewel itself but also that of
other precious objects such as watches, sculptures, porcelains, and
other art works which have the diamond firmly attached to it.
[0006] In accordance with one aspect of the present invention there
is provided a method for engraving an irreproducible pattern on the
surface of gemstone by controlling the pixel dwell time, exposure
sequence, and the incident angle of said energetic ion beam with
respect to the surface normal of said gemstone.
[0007] In accordance with another aspect of the present invention
there is provided a gemstone having a surface on which is a pattern
which has been applied using said method.
[0008] In accordance with yet another aspect of the present
invention there is provided a precious object which is permanently
attached to said gemstone.
[0009] More specifically, the present invention provides a method
for engraving an irreproducible pattern on the surface of a
diamond, comprising the step of exposing an energetic ion beam onto
the surface of the diamond at an angle from the normal of the
surface of about 45.degree.-85.degree.. Preferably, the angle is of
about 50.degree.-70.degree.. More preferably, the angle is of about
55.degree.-65.degree., most preferably the angle is of about
60.degree.. The method may engrave a second pattern on the surface
of the diamond. This second pattern may be as large as the area of
the surface of the diamond, and may optionally be a photograph,
printed character, drawing, or signature.
[0010] The energetic ion beam used to engrave the irreproducible
pattern may be a focused ion beam. Preferably the diameter of the
focused ion beam is about 5 nm.
[0011] An alternative method for engraving an irreproducible
pattern on the surface of a diamond comprises positioning a mask
between an output of an ion beam and the surface of the diamond,
and exposing the ion beam on the exposed area of the mask at an
angle from the normal of the surface of about
45.degree.-85.degree.. Preferably, the angle is of about
50.degree.-70.degree.. More preferably, the angle is of about
55.degree.-65.degree., most preferably the angle is of about
60.degree.. The step of positioning a mask may comprise the steps
of covering the surface of the diamond with a resist layer; and
removing selected portion(s) of the resist layer to expose an area
or areas to said energetic ion beam.
[0012] The energetic ion beam may be a broad ion beam, such as
Ar+.
[0013] The present invention also provides for a novel diamond
having a surface on which a pattern has been applied using the
methods described above.
[0014] The present invention also provides a method of
authenticating an object by permanently attaching to the object a
diamond having a surface on which is a pattern has been applied
using the methods described above.
[0015] These and other aspects, objects, features, and advantages
of the present invention will be more clearly understood and
appreciated from a review of the following detailed description of
the preferred embodiments and appended claims, and by reference to
the accompanying drawings. It is to be understood, however, that
the drawings are designed solely for purposes of illustration and
not as a definition of the limits of the invention, for which
reference should be made to the appended claims. It should be
further understood that the drawings are not necessarily drawn to
scale and that, unless otherwise indicated, they are merely
intended to conceptually illustrate the structures and procedures
described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In the detailed description of the preferred embodiments of
the invention presented below, reference is made to the
accompanying drawings in which:
[0017] FIG. 1 is a schematic showing that a FIB is scanned over the
predetermined area of a diamond to engrave a desired pattern.
[0018] FIG. 2(a) is a schematic showing a logo of the Institute of
Atomic and Molecular Sciences,
[0019] FIG. 2(b) is a schematic showing a miniature version of the
logo engraved on a diamond surface by FIB lithography (full scale
of the FIB image is 4 .mu.m).
[0020] FIG. 3 is a schematic showing that a broad ion beam is used
to sputter remove carbon from the area on a diamond surface that is
no longer protected by the resist layer after photolithography is
performed.
[0021] FIG. 4(a) is a scanning ion microscope image of the
fingerprint-like texture produced by the method of the present
invention, and
[0022] FIG. 2(b) is the detailed topology of the fingerprint-like
texture.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0023] The invention has been described in detail with particular
reference to certain preferred embodiments thereof, but it will be
understood that variations and modifications can be effected within
the spirit and scope of the invention.
[0024] FIG. 1 shows a schematic for one of the processes that can
be used to create a pattern on the surface of a diamond. The
function of the focused ion beam (FIB) is analogous to a chisel
which allows a sculptor to engrave a pattern or symbol onto a
stone. By dwelling the FIB over a specific spot on a diamond,
certain number (sputtering yield) of carbon atoms is sputtered away
from its surface, leaving a small crater with a size approximately
equal to the beam diameter of the FIB. Since the current FIB
technology can create a beam with a diameter as small as .about.5
nm, it is, in principle, possible to create patterns with .about.10
nm spatial resolution. On the other hand, the size of the entire
pattern can be as large as the diamond itself.
[0025] In a typical FIB lithographic process, a digital version of
the pattern to be created is stored in the computer, which controls
the magnification of the pattern to be drawn, the dwell time for
each pixel, and sequence of the pixel to be exposed. The sample is
always mounted on a stage that can be rotated, tilted, and moved
along x-y-z directions. By changing the pixel dwell time, exposure
sequence, and the incident angle of FIB with respect to the surface
normal of a diamond, it is possible to create a miniature version
of the desired pattern with a characteristic texture on the
nanometer scale. Preferably, the ion beam is directed onto the
surface of the diamond at an angle of about 45.degree.-85.degree.
from the normal of the surface. More preferably, the angle is of
about 50.degree.-70.degree. or about 55.degree.-65.degree., and
most preferably the angle is of about 60.degree..
[0026] For example, the logo of the Institute of Atomic and
Molecular Sciences in Academia Sinica, as shown in FIG. 2(a), is
first stored as a digital file in the computer, which then directs
the FIB to the desired area and engraved a miniature version of the
logo on a diamond surface, as shown in FIG. 2(b). The most
important feature to be noted in this image is the fingerprint-like
texture on the logo and its surrounding area. The texture is
spontaneous formed during the ion bombardment process; and one can
only control its general outline and impression rather than the
topological details. Specifically, it can not be reproduced even by
using the same FIB to conduct the lithography at the exactly
identical experimental conditions. It is this irreproducible
texture on the nanometer scale that allows us to certify the
authenticity of the diamond carrying this unique symbol. Such
`nano-texture` is very much like the unique style or patterns that
usually appear on the sculptures by a particular sculptor using a
specific cutting technique. Another example of this nano-texture is
exhibited in FIG. 4, which shows a scanning ion microscope image of
the nano-texture along with a determination of its topography.
[0027] An alternative way, as shown in FIG. 3, in order to create a
nano-textured pattern on a diamond is to have its surface first
covered by a resist layer, then photolithography is used to expose
the area that is to be sputtered by the broad ion beam such as Ar+.
Depending on the conditions used for the ion sputtering, patterns
with characteristic nano-texture similar, but not identical, to
that produced by FIB-sputtering can also be created on the
diamond.
[0028] The third method is to combine the high speed of a broad ion
beam and the high precision of focused ion beam to create a
combination of large and small patterns with different
characteristic nano-texture on the surface of diamond. With its
high throughput and precision, such a hybrid patterning process
would certainly be the most desirable way for a large scale
manufacturing.
[0029] Once a diamond is marked with irreproducible nano-textured
patterns, it can also be used to certify the authenticity of other
precious objects such as art works. For example, the diamond can be
firmly attached to watches, sculptures, or porcelains to not only
enhance their beauty but also certify their authenticity. Depending
on the material of the object to be certified, there are various
ways to permanently attach the diamond to its surface. As used
herein, a permanent attachment is defined as the formation of a
strong bond between two objects such that any attempt to separate
them would result in the damage of one or the other.
[0030] The invention is not limited by the embodiments described
above which are presented as examples only but can be modified in
various ways within the scope of protection defined by the appended
patent claims. All cited references are herein incorporated by
reference in their entirety.
* * * * *