Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Scanner with Waveguide for Scanning Paper Currency
The present invention, in general, is directed to scanners. More particularly,
the present invention is directed to an apparatus and method for scanning
paper
currency for the purpose of verifying the authenticity as well as determining
the
value thereof.
Conventional paper-currency scanning devices are, e.g., typically associated
with vending machines that provide consumers with beverages and snacks as well
as
separate mechanisms located in, e.g., recreational areas having casino slot
machines
that accept paper currency and/or video arcades that provide coins in exchange
for
paper currency. Such scanning devices typically employ a light source to
illuminate
the currency as well as a detector system that picks-up features or
characteristics
from the currency.
The United States government, e.g., has recently introduced an assortment
of bills that include noticeably asymmetric indicia such as portraits of
familiar
individuals, and which incorporate other unique features and characteristics
that
make counterfeiting its paper currency more difficult than ever. Additionally,
a
number of other countries have paper currencies that may vary in color as well
as
dimension, depending upon valuation.
As a result of such security measures, a number of conventional paper
currency-scanning devices and systems further frequently incorporate at least
one
light source as well as an associated collimating lens for producing a beam of
substantially parallel light rays that pass through and illuminate the paper
currency
from one side thereof.
Typically located on the opposite side of the illuminated currency is an
associated planar/convex lens for gathering scatter rays from the bill, and
which
thereafter provides the gathered scatter rays to an associated detector that
is
designed, in ideal situations, to be capable of verifying the authenticity as
well as
detecting the value of the scanned bills.
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Also, the convex lens is typically so spaced from a desired scanning plane
(for the paper currency) such that the focal point of the lens ideally touches
the
scanning plane.
Accordingly, in ideal situations, indicia and other characteristics
incorporated into current paper currency for security reasons are capable of
providing light passing through the scanned bill with information that is
compared to
certain stored information, for the purpose of verifying authenticity as well
as value
of the paper currency being scanned.
However, movement of the paper currency above or below its desired
scanning plane may take the bill out of the lens focal point. To both
collimate and
focus light on a point poses design constraints, especially in view of the
fact that
displacement of as little as one (1) millimeter away from a desired focusing
position
may move the focal point out of its associated desired viewing position.
Moreover,
paper currency that is torn, taped, discolored, very creased or wrinkled, or
worn
thin may further aggravate the problem.
Further still, paper by its nature diffuses light. As a result, diffused light
passing through a bill located in the desired scanning plane, which is
thereafter
focused, may fall short of the detector entirely, or the light rays passing
through the
convex lens may focus light from the scanned bill behind a desired detection
zone,
either of which is undesirable.
Accordingly, when comparing information from a scanned bill to such
calibration information, there can be a disparity between the bill and stored
calibration information as well as non-compliance of certain wavelengths of
light,
for reasons mentioned above.
Disparity between the scanned bill and the calibration information may be
within design tolerance of many conventional currency-scanning devices, with
the
result that the scanned bill is accepted. Non-compliance of wavelengths,
however, is
another matter.
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To solve such problems, conventional currency-scanning devices may
include, as the light sources thereof, certain light-emitting diode devices
(or so-
called "packages"), that are capable of providing light of multiple
wavelengths.
Conventional scanners may therefore incorporate a plurality of such state-of
the-art light-emitting diodes (LEDs), for the purpose of "solving" a perceived
problem.
In this regard, a single currently commercially-available LED package
capable of operating from blue to infrared, when incorporated into the above-
described conventional currency-scanning device, is able to provide the
scamiing
device with a source of light having the characteristic wavelengths of 470,
505, 620,
730, 840 and 940 nanometers.
Unfortunately, state-of the-art paper currency-scanning devices, of current
design, often incorporate twelve or more of the above-described LED packages,
if
such scanning devices are to verify currency authenticity and value, to meet
their
commercial purpose.
For a number of reasons, it would therefore be desirable to reduce the
number of presently available LED packages described above from twelve or more
to as few as four.
SUMMARY OF THE INVENTION
The present invention is directed to a scanner apparatus that does not require
a collimating lens. Instead, the scanner apparatus incorporates a waveguide.
Moreover, the resulting design of the scanner apparatus of the invention has
enabled
reducing the number of light-emitting diode (LED) packages from twelve or more
to
four or less.
The scanner apparatus of the invention is preferably used to scan paper
currency for the purpose of verifying the authenticity as well as determining
the
value thereof.
Also, when the scanner apparatus of the invention incorporates four such
LED packages, each such LED package is preferably so disposed and positioned,
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relative to the currency-scanning plane, as to scan a different quarter
portion of the
paper currency.
Accordingly, the scanner apparatus of the present invention comprises a .
scanning zone, at least one light-emitting diode, at least one light detector,
and a
waveguide.
The scanning zone of the scanner defines opposed sides and is dimensioned
to enable a scannable article to be disposed between the opposed sides
thereof.
The light-emitting diode device is disposed on one side of the scanning zone,
and is capable of providing light of discreetly-different energy levels. Also,
the
light-emitting diode device is so disposed relative to the scanning zone as to
enable
light associated with such diode device to be able to scan at least a portion
of the
scannable article.
The light-detector device is spaced from the light-emitting diode, and is also
so disposed relative to the scanning zone of the scanner, that light emanating
from
the light-emitting diode device and thereafter passing through the scanning
zone, is
able to provide information, enabling the light detector to characterize the
article
scanned in the zone.
The wave guide is disposed between the light-emitting diode device and
scanning zone. The wave guide defines at least one light-admitting aperture
and at
least one light-reflective surface, wherein the light-admitting aperture and
the light-
reflecting surface cooperate to direct Iight from the light-emitting diode
device
toward the scanning zone, and to focus such light centrally along a path
traveled by
such light toward the detector.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic view of a conventional apparatus for scanning
currency.
Figure 2 is a schematic view of a first embodiment of the scanner apparatus
of the present invention.
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Figure 3, also a schematic, shows a lower portion of the embodiment of
Figure 2.
Figure 4 is a bottom plan view taken generally along the plane 4-4 of Figure
3.
Figure SA is a schematic view that depicts an illustrative example of a
feature of the present invention generally shown in Figure 3, on an enlarged
scale
relative thereto.
Figure SB is another schematic depicting a further illustrative example of the
noted feature generally shown in Figure 3, also on an enlarged scale relative
thereto.
Figure 6 depicts, in side view and in a schematic format, yet another
preferred embodiment of the scanner apparatus of the present invention.
Figure 7 depicts, in side view and also in a schematic format, still another
preferred embodiment of the scanner apparatus of the present invention.
Throughout the drawings, like reference numeral refer to like component
parts.
State-of the-Art Scanner and Problems Associated Therewith
Figure 1 depicts, as a schematic view, a conventional apparatus 100 for
scanning paper currency. The apparatus 100 includes an opening or aperture 102
typically taking the form of an elongated slot for inserting paper currency
into the
apparatus 100.
The currency-insertion aperture or opening 102 includes an upper boundary
104 and a lower boundary 106. Currency (not shown) inserted through opening
102
into the apparatus 100 ideally is caused to travel along a path 110 (shown in
dotted
line) that may be thought of as a plane extending into the page of Figure 1 of
this
patent specification.
The currency-scanning apparatus 100 also includes a plurality of light-
emitting diodes (LEDs) 114 that are spaced from the lower boundary 106
generally
uniformly along the length thereof. As was noted above, twelve or more of the
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above-described LED packages 114 must necessarily be incorporated into the
scanning apparatus 100, if the apparatus 100 is to verify currency
authenticity and
value, thereby to achieve its commercial purpose.
Also incorporated into the conventional arrangement depicted in Figure 1 is a
corresponding plurality of collimating lenses 116, wherein each lens 116 is
similarly
spaced from the lower boundary 106 generally uniformly along the length
thereof.
In the conventional scanner arrangement illustrated, each such collimating
lens 116
is associated with its corresponding LED package 114. Accordingly, as a result
of
the scanner arrangement shown, each such collimating lens 116 is located
between
the lower boundary 106 and its associated LED package 114.
The currency-scanning apparatus 100 of Figure 1 further includes a
corresponding plurality of simple planar convex light-focusing lenses 122.
Each
such simple planar convex light-focusing lens 122 is disposed between the
upper
boundary 104 and an associated currency authenticity/valuation detector 120.
In ideal situations, each such simple planar convex light-focusing lens 122 is
capable of focusing light passing through the paper currency onto a
preselected
portion (or point) of its associated detector 120.
In operation, the plural simple planar convex light-focusing lenses 122 focus
light to enable the plural detectors 120 to detect certain light-energy
levels, for the
purpose of verifying the authenticity of the inserted currency as well as
detecting the
value thereof.
The currency-scanning apparatus 100 shown in Figure 1 accordingly
necessarily further includes a corresponding plurality of detectors 120, each
of
which is capable of verifying the authenticity of currency and detecting the
relative
value thereof.
Moreover, the plural detectors 120 (i.e., twelve or more) are by current
design spaced from the upper boundary 104 generally uniformly along the length
thereof. Each detector 120 is associated with a corresponding light-focusing
lens 122
as well as with a corresponding LED package 114 and collimating lens 116, for
reasons stated above.
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Conventional scanners still have problems. As was mentioned above,
movement of paper currency above or below its desired scanning plane may take
the
bill out of the focal point of light-focusing convex lens 122. Also, paper by
its
nature diffuses light. As a result, even when a conventional apparatus 100
incorporates the plural LED packages 114 described above and the associated
pluralities of collimating lenses 116, convex lenses 122, and detectors 120,
the
resultant diffused light that passes through a bill located in the scanning
plane 110, ,
which light is thereafter focused, may fall short of one or more of the plural
detectors 120 entirely, or the light rays passing through one or more of the
plural
convex lens 122 may focus light from the scanned bill behind a desired
detection
zone of an associated detector 120, either of which result is undesirable.
Aligning each LED package 114 with associated lenses 116 and 122 is a
major obstacle faced by current scanner manufacturers and misalignment is
common.
Unnecessary complexity may result in excessive cost of the apparatus, and
may affect reliable operation thereof. It is therefore desirable to reduce the
complexity of a scanner apparatus by reducing the number of LED packages and
associated components now required in state-of the-art paper-currency
scanners,
thereby allowing for reduction of the above mentioned associated components,
resulting in a less complex apparatus.
Multiplicity of component parts may undesirably impact on volume .
requirements and associated appearance considerations of conventional
scanners. To
minimize volume requirements, reduction of the number of components may
therefore become desirable.
It is further desirable that the resultant less-complex apparatus nevertheless
be capable of verifying the authenticity of currency and determining its
denomination or value with very high reliability and accuracy and
statistically
significant precision.
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Detailed Description of Preferred Embodiments
Figure 2 depicts, in schematic, one embodiment of the scanner apparatus 200
of the present invention. Apparatus 200 is preferably used to scan paper
currency to
verify authenticity and determine the value thereof.
Currency-scanner apparatus 200 includes no more than four light-emitting
diode packages 214, the location of which will be described below in
connection
with Figure 4.
Each such light-emitting diode (LED) package 214 is able to produce light
having a plurality of discreetly-different wave lengths, each of which has a
discrete
energy level. Preferably, each LED package 214 is capable of producing light
having two to ten discretely different energy levels. More preferably, each
LED
package 214 is able to produce light having four to eight discretely-different
energy
levels depending on the wavelengths. The most preferred LED package 214 (shown
in Figure 4) is capable of producing light having six different energy levels.
In
particular, the most preferred LED package 214 of the currency scanner
apparatus
200 is able to produce light having associated discretely-different
wavelengths of
470, 505, 620, 730, 840 and 940 manometers. In particular, Figure 4 depicts
schematically six apertures on LED package 214, wherein the apertures 218A,
218B, 2180, 218D, 218E and 218F are each associated with a different one of
the
six wave lengths of light that are mentioned immediately above.
The scanner apparatus 200 of the present invention does not require a
collimating lens. Instead, the scanner apparatus 200 of the invention includes
a wave
guide 230. Wave guide 230 includes polished clear windows 232 located on
opposite
ends thereof. The windows 232 are so disposed relative to an associated LED
package 214 as to enable light from such associated LED package 214 to enter
the
wave guide 230.
The illustrated wave guide 230 further includes side surfaces 234 as well as a
grooved surface 236 for directing light from the LED packages 214 toward the
direction of paper currency that is caused to travel along a path 210 (shown
in
dotted line) that may be thought of as a plane extending into the page of
Figure 2 of
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this patent specification. Side surfaces 234, disposed at opposite ends of
wave guide
230, are metalized. Each metalized surface 234 is so disposed relative to an
associated LED package 214 as to direct light from such LED 214 toward
scanning
path 210, as described above.
Grooved surface 236 includes individual grooves 238-240, depicted
schematically in Figures 3 and 4. Each groove 238 shown is illustrative of a
groove
formed at an upper junction of angled adjacent surface portions of grooved
surface
236. Whereas, grooves 239 and 240 are illustrative of grooves formed at an
intermediate junction and at a lower junction, respectively, of angled
adjacent
surface portions of the grooved surface 236.
Grooved surface 236 is symmetric about axis A-A (Figure 3) for several
reasons. First, the light sources (provided by the LED packages 214) are
longitudinally disposed at opposite ends of the wave guide 230. Also, the
angled
side surfaces 234 of the wave guide 230 are so disposed relative to their
associated
LED packages 214 as to concentrate reflected light of six discrete, different
wavelengths toward central axis A-A. Moreover, the grooved surface 236,
itself, is
made up of minute illustrative grooves 236A (Figure SA) and grooves 236B
(Figure
SB), designed to concentrate light centrally.
Further in that regard, grooves 236B (Figure SB), which are triangularly
formed and located closer to windows 232, are so dimensioned as to cause a
first
portion of the six wavelengths to so reflect from the side surfaces 234 and
grooved
surface 236 as to be concentrated centrally toward axis A-A. Proceeding closer
to
central axis A-A minute grooves 236A are even more closely spaced (Figure SA)
so
as to cause a second portion of the six wavelengths of light from LED packages
214
to be concentrated centrally toward axis A-A. Additional minute grooves (not
shown) are accordingly symmetrically formed in the grooved surface 236
relative to
the central axis A-A until all six wavelengths of light from LED package 214
are
centrally concentrated.
Brief reference is made to Figure 3 to note that the depicted angled
orientation of grooved surface 236 must further consider the angle orientation
of the
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associated minute grooves 236A (Figure SA) and 236B (Figure SB) to achieve the
effects disclosed herein.
Grooved surface 236, by design, thus includes minute grooves, the
dimensions of which diminish symmetrically toward central axis A-A, to
5 accommodate the different frequencies of the six different wave lengths,
enabling
light of uniform intensity to scan paper currency along path 210. The net
effect,
which is cost efficient, is a uniform "bar" or rectangle of light, produced as
a result
of using a minimal amount of light energy.
The illustrated wave guide 230 (Figures 2 and 3) is a so-called "dove" prism
10 made of a commercially-available acrylic material which is both highly
transparent
and able to transmit light with high efficiency, thus achieving substantially
total
internal reflection.
The side surfaces 234 and grooved surface 236 are metalized with
commercially-available highly reflective material for reflecting light
centrally
toward axis A-A and path 210, as noted above. Further in this regard, grooved
surface 236, itself, is especially designed to concentrate light of discretely-
different
wave lengths and associated energy levels uniformly toward an article such as
currency being scanned by apparatus 200.
In Figure 6, there is shown a scanner apparatus 300 that includes wave guide
330 and LED packages 314, and spaced-apart light-reflective side surfaces 334
disposed on opposite longitudinal ends of wave guide 330. Wave guide 330
further
includes a pair of spaced-apart polished, clear light-transmissive windows
332, each
of which is so located adjacent an associated LED package 314, as to achieve a
"light bar" effect noted above.
In lieu of a grooved surface (described above) this embodiment of the
invention incorporates into the design of the illustrated wave guide 330 a
holographic, variable light-shaping diffuser surface 350 between the windows
332,
The light-shaping diffuser surface 350 is upwardlylight-reflective, as a
result of a
layer of commercially-available metallic material 352 that is applied to the
underside
thereof. In particular, the variability that is incorporated into the light-
shaping
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diffuser surface 350, using techniques disclosed for example in a commonly
assigned copending patent application, is able to achieve the same effect of
the
variably grooved surface 236 of scanner apparatus 200, to focus within wave
guide
330 internally-reflected light toward central axis B-B of apparatus 300 and
upwardly, achieving the noted "light bar" effect, for the purpose of scanning
an
article.
To achieve such an effect, a central portion 360 (depicted in Figure 6
between vertically-disposed dotted lines) preferably has a major light output
distribution angle of 80 to 95 ° along the length as well as a minor
light distribution
angle of 25 to 35 ° across the width of paper currency being scanned.
Light-shaping
diffuser surface 350 further includes spaced-apart end portions 362, each of
which is
located adjacent an associated LED package 314. Further, each portion 362
preferably has a major angle of 60 to 75 ° along the length as well as
a minor angle
of 10 to 25 ° across the width of currency scanned along path 310 by
scanner 300.
To receive the centrally-concentrated, upwardly-disposed light from the
light-shaping diffuser surface 350 of wave guide 330, the apparatus further
includes
a light-shaping surface diffuser layer 370 disposed above wave guide 330, as
shown
in Figure 6.
Layer 370 also preferably has a major light distribution angle of 80 to 95
along the length as well as a minor light distribution angle of 25 to 35
° across the
width of paper currency being scanned, as does central portion 360. Moreover,
layer 370 and central portion 360 have their light-shaping diffuser major and
minor
angle orientations aligned, to achieve the above-noted effect.
An optional sheet of commercially-available prismatic material 380 may then
be disposed on the opposite side of path 310 relative to light-shaping surface
diffuser
layer 370, to reduce the effect of light coming off of the backside of
currency being
scanned.
Yet another embodiment of the scanner apparatus 400 of the present
invention, as shown in Figure 7, includes wave guide 440 and light-shaping
surface
diffuser layer 470 disposed thereabove, as in scanner apparatus 300. (Please
refer to
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Figure 6.) A plurality of detectors 420, located on the opposite side of path
410
relative to wave guide 440, are so disposed relative to each other along the
length of
path 410 as to verify the authenticity as well as determine the value of
currency
being caused to travel along path 410 by use of a conventional mechanism (not
shown). A single row of detectors 420 may include eight to twelve individual
detectors 420, depending on dimensions of scanned currency.
A sheet of commercially-available prismatic material 480 is disposed
between path 410 and the light-shaping surface diffuser layer 470, to reduce
the
effect of light scattering, and~collimating the light between diffuser layer
470 and
path 410. Between detectors 420 and path 410 is at least one sheet of another
commercially-available prismatic material 482, which preferably has its
prismatic
grooves (not shown) disposed longitudinally relative to the currency that is
caused to
travel along path 410, namely, out of the plane of the page of Figure 7. An
additional sheet of still another commercially-available prismatic material
484 may
be disposed between prismatic material sheet 482 and detectors 420, to reduce
the
effect of light scattering between path 410 and detectors 420.
What has been illustrated and described herein is a novel scanner apparatus
for paper currency. While the scanner apparatus of the present invention has
been
described with reference to several preferred embodiments, it is to be
understood
that those skilled in the art, after reading this disclosure, will appreciate
the value of
the invention, and will know of certain equivalents of elements and components
disclosed herein. The present invention, therefore, is not to be limited to
the
presently preferred embodiments, but rather is to be provided the broadest
possible
scope, as the appended claims will permit.
