Note: Descriptions are shown in the official language in which they were submitted.
21~5233
This invention relates to an authenticatable, l~min~ted article.
It has already been proposed in United States Patent No.
3.665,483. dated May 23, 1972, " Laser Recording Medium", C. H.
5 Becker et al, to provide a recording medium for the permanent
storage of data by selective laser beam ablation of a layer of energy -
absorbing material . The recording medium is a heat reflecting layer
o~, for example rhodium sputtered on to a substrate of, for example,
MYLAR (trade mark) or CELANAR (trade mark), and covered by a
10 transparent, protective layer of, for example, S i 2
It as also been proposed in United States Patent No.
4,544,181, dated Oct. 1, 1985, " Identification card", T. Maurer et al,
to provide a multi-layered identification card comprising an opaque
15 card core of, for example, paper, l~min~ted between two cover sheets
of, for example, polyvinyl chloride. At least one of the cover sheets is
transparent so that information provided on the core by thermally,
irreversibly degrading core portions, which also is formed in register
therewith in the cover sheet, is visible as a validating feature
20 through the transparent cover sheet and may be manually inspected
by virtue of a permanent relief-type structure produced in the cover
sheet providing an secondary validating feature.
While the devices of Becker et al and Maurer et al are useful,
25 there is a need for a more readily discernible, more distinguishing,
harder to reproduce, and more complex, secondary validating feature
21~S233
on these devices, than the permanent relief-type structure taught by
Maurer et al.
According to the present invention there is provided an
5 authenticatable, l~min~ted article, comprising,
a) an inner, laser beam markable, core layer,
b) two protective layers, with the core layer sandwiched
therebetween and visible through at least one of the
protective layers, which is capable of transmitting a
laser beam for marking the core layer,
c) a viewing angle sensitive, optical interference,
authenticating, l~min~te device on the side of the core
layer at which the said at least one of the protective
layers is disposed, at least a portion of the core layer is
visible through the optical interference laminate device
at at least one viewing angle, and the optical
interference l~qminAte device is capable of transmitting a
laser beam for marking the core layer, and
d) an adhesive layer, through which any laser markings on
the core layer are visible, att~çhing the optical
interference, l~min~te device to the other components of
the article, the adhesive layer being capable of
transmitting a laser beam for marking the core layer.
In this specification authenticatable, l~min~qted article
includes authenticatable, laminated labels and identity cards, teller
cards and the like.
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The laser beam transmitting protective layer, optical
interference layer and adhesive layer allow the core to be marked
through those components.
In this specification, capable of transmitting a laser beam for
marking the core layer, means capable of transmitting a laser beam
at the operating wavelength of a laser source used to mark the core
layer.
The said at least one protective layer may also be a protective
layer for the optical interference l~min~qte device.
The protective layers may be of a substance selected from the
15 group consisting of polycarbonate, polyvinyl chloride, a polyester, and
a polyamide.
The adhesive layer may be a h e a t a c t i v a t e d adhesive of a
substance selected from the group consisting of acrylated urethane,
20 non-acrylated urethane, polyvinylidene chloride, ethylene-vinyl
acetate copolymer (EVA) and an epoxy adhesive.
The core layer may be a blank for subsequent marking by the
laser beam.
The core layer may have been marked by a laser beam.
215~33
The core layer may have been marked by a laser beam which
has displaced a portion of the optical interference layer.
In the accompanying drawings which illustrate, by way of
6 example, an embodiment of the present,
Figure 1 is an enlarged diagrammatic, sectional end view
along I-I, Figure 2,
Figure 2 is a plan view of Figure 1, and
Figure 3 is another enlarged, diagrammatic sectional end view
along I-I, Figure 2, but of a different embodiment to that shown in
Figures 1 and 2.
Referring now to Figure 1 and 2 there is shown an
authenticatable, l~qmin~ted article 1, comprising,
a) an inner, laser beam markable, core layer 2,
b) two protective layers 4 and 6, with the core layer 2
sandwiched therebetween and visible through at least
one, of the protective layers 4 and 6, in this
embodiment 4, which is capable of transmitting a laser
beam for marking the core layer 2,
c) a viewing angle sensitive, optical interference,
26 authenticating, l~min~te device 8 on the side of the core
layer 2 at which the said at least one 4 of the protective
layers 4 and 6 is disposed, at least a portion of the core
21S523~
layer 2 is visible through the optical interference
lAmin~te device 8 at at least one viewing angle, and the
optical interference l~qmin~te device 8 is capable of
transmitting a laser beam L for marking the core layer
2 with a mark such as 10, and
d) an adhesive layer 12, through which any laser
markings, such as 10, on the core layer 2 are visible,
att~ching the optical interference, l~3min~te device 8 to
the other components of the article 1, the adhesive layer
12 being capable of transmitting the laser beam L for
marking the core layer 2.
The laser beam L, to mark the core layer 2, is arranged to
enter the optical interference, l~min~te device 8 at an angle of
incidence 'a' thereto, which in this embodiment is 0, at which no
damage is done to the optical interference, l~min~te device 8.
In Figure 3, similar parts to those shown in Figure 1 and 2 are
designated by the same reference numerals and the previous
description is relied upon to describe them.
In Figure 3, the optical interference l~min~te device 8 is on the
core layer 2, and the protective layer 4 is also a protective layer for
the optical interference l~min~te device 8, which is also visible
therethrough.
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A further feature, which is included in the embodiment shown
in Figure 2, is that the intensity of the laser beam L has been
adjusted so that a relief 14 is formed over the marking 10, which
displaces the optical intel-ference l~qmin~te device 8, the adhesive
5 layer 12, and the protective layer 4. This displacement of the optical
interference l~min~te device 8 gives an added complexity to the
optical interference characteristics thereof.
The core layer 2 may be of any material or combination of
10 materials which can be discolored by a laser beam and which will
render laser markings thereon discernible, such as, for example,
laser degradable plastic which may be transparent or opaque, paper
alone, which may be burned or subjected to carbonization, or
discoloration of a thermosensitive coating applied to an inlay, or a
15 metal such as rhodium coated with SiO2 or Al203 as an
antireflective layer. All of these types of materials for the core layer
2 are known in the art.
The protective layers 4 and 6 may be of any suitable material
20 which will not be degraded by the laser beam, suitable materials are,
for example, polycarbonate, polyvinyl chloride, a polyester or
polyamide.
The viewing angle sensitive, optical interference,
26 authenticating, l~rnin~te device 8 may comprise at least one vapor
deposited, light transmitting coating selected from the group
consisting of Al, Inconel, SiO2, A103, ZnO2 and ZnS, MgF2. The
-G-
21 SS233
-
materials are disclosed in "Optical Document Security", Chapter 12,
"Optical Thin-Film Security I?evices", J. A. Dobrowolski, pages 227-
261, published by Artech House, Boston. London.
The adhesive layer 12 nlay be a h eat activated adhesive
selected from the group consisting of acrylated or non-acrylated
urethane, polyvinylidene chloride, ethylene-vinyl acetate copolymer
(EvA)andanepoxyadhesive. The adhesive layer 12 may be
thermosetting or thermoplastic,
The viewing angle sensitive, optical interference,
authenticating, l~min~te device 8, in some embodiments of the
present invention, only partially covers or partially overlaps the core
layer 2, while in other embodiments either of these components
either of these components may extend over a larger area than the
other one.
The present invention allows, for example, a card or label to
have the core layer, protective layers, optical interference l~min~te
device, and adhesive layer to be assembled and then the core laser
marked, or the assembly sold as a blank for the core layer to be laser
marked by a purchaser, giving added security in that any
disturbance or degradation during marking, that occurs to any
components other than the core layer is registered with the markings
on the core layer and is difficult if not impossible to realign if the
article is tampered with.
