Note: Descriptions are shown in the official language in which they were submitted.
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Descriptlon
Dual Stripe Optical ~ata Card
Technical Field
The invention relates to optical information
storage.
Background Art
In U.S~ patent 4,360,728, Drexler describes a
data card having a laser recording, direct-read-after-
write (DRAW~ stripe, alongside a magnetic stripe, the two
stripes workiny in cooperation.
Maurer et al. in U.S. patent 4,467,209 dis-
closes an identification card having erasable and non-
erasable data. The erasable medium is suggested to be
magnetic, while the non-erasable medium is a laser
recording material or an integrated circuit
Dil, in U.S. patent 4,209,804, teaches a re-
flective information recording structure which contains
prepressed V-shaped grooves in which data may be recorded
by local melting of the reflective metal coating by a
laser. The data on the media is read by means o~ optical
phase shift effects. Since the preformed grooves are at
an optical phase depth of 95 to 140, the reading laser
must be of the precise wavelength corresponding to the
groove depth. The information area has a width of ap-
proximately 0.6 microns, so a thick protective substrate,
usually 1200 microns deep is used to ensure that one
micron surface dust particles are out-of-focus for the
read beam.
Such thick protective materials cannot be used
for wallet cards which have a total thickness of only 800
microns under ISO ~International Standards Organization)
standards and further it would be uncomfortable to carry
a rigid card in trouser pockets or wallets. Also, it is
difficult to bond a phase sensitive recording/reading
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surface to a protective laminating material with an adhe~
sive without introducing a varying phase shift across the
surface. It is also impractical to mel~ large holes
since a large lip would be formed around the hole
causing a greak distortion of the phase shift. Edge
transition of the hole is the phase shift which is
measured, and since the height of the lip is directly
proportional to the square root of the hole diameter,
phase shift reading is only practical for small holes.
For example, a 25 micron diameter hole creates a lip with
one micron height, which is much larger than the wave- -
length of the reading beam. Thus for large holes and
bonded protective materials it is desirable to have a
recording/reading structure that does not rely on phase
shifts.
~ Lahr in U.S. patent 3,873,813 teaches a debit
card in which use is indicated by alteration of a spot of
heat sensitive coating in a selected area thereby per-
manently changing the reflective characteristics of that
area. A reflective heat sensitive material becomes
transparent on heating, thereby exposing an underlying
strip of black paper which then absorbs the light energy.
Recording requires exposure to a high intensity light
beam for 0.7 second to raise the temperature of the
material to 17~ F and an additional 5 milliseconds above
175F. This type of credit card system permits recording
of less than two data bits per second. Because of the
retained, diffused liquid, the sizes of the data spots
are large and difficult to regulate. This card requires
a blue read beam, therefore scratches and surface dust
will cause a large number of data errors unless very
large data spots are used that reduce capacity to under
10,000 bits. While this data capacity is satisfactory
for some debit and credit cards, it is unsuitable for
detailed recording of financial, insurance, medical and
personal records.
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Nagata in U.S. patent 4,197,986, Girard in
U.S. patent 4,224,666 and Atalla in U.S. patent 4,304,990
teach updating of data cards. Nagata teaches the up-
dating of maximum limits and balance on a card in which
the complete data file is in an auxiliary memory circuit
such as a magnetic disc or drum. A sales slip containing
the transaction is recorded separately from the card.
Giraud teaches a data-processing machine-access card
containing an integrated circuit chip with a memory bank.
The memory stores predetermined items of confidential
data intended to authorize or prevent access to the
machine. Only the balance is updated.
Atalla teaches a card in which only the balance
is recorded and updated. This card can only be used
where the transaction system is connected to a central
computer. None of these cards has the memory storage
capacity needed to accumulate records of past transac-
tions.
Gupta et al. in U.S. patent 4,527,173 teach an
erasable, reusable recording medium having a heat-deform-
able optical recording layer with a transparent overcoat.
In TJ.S. patent 3,530,441, Ovshinsky teaches an
erasable recording medium wherein amorphous silicon is
locally converted to crystalline silicon with concomitant
changes in optical reflectivity.
In U.S. patent 4,425,570 Bell et al. teach an
erasable optical recording medium composed of a metallic
granular material in a dielectric matrix. The metal
particles are of a type which absorb light at the re-
cording wavelength and reversably switch from an originalstate to a second state having different optical proper-
ties at a readout wavelength. An erasing light beam or
heat is able to restore the material to its original
condition.
Various recording media have been developed for
use on a rotating disc format. Because the disc is
spinning rapidly, short laser pulse times (on the order
of 500 nanoseconds) are necessary to confine the heating
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to small spots. The media have been developed to in-
crease the sensitivity to the beam by varying the para-
meter of media absorptivity. Spong in U.S. patents
4,190,843 and 4,305,081 puts an absorptive dye layer over
a reflective aluminum layer. Spots are recorded by abla-
tion of the dye layer exposing the underlying reflective
layer. Bell in U.S. patent 4,300,143, teaches a similar
technique. Bartolini in U.S. patent 4,313,188 adds a
protective layer between the dye layer and the reflective
layer. Wilkinson in U.S. patent ~,345,2~1 uses a light
absorptive ~ilica dielectric layer in place of the dye
layer. Terao teaches an inorganic absorptive layer over
an organic recording film layer. Holes are formed in the
film layer by heat generated in the absorptive layer.
Suzuki in U.S. patent 4,202,491 uses a fluorescent ink
layer on which data spots emit infrared radiation. Mag-
neto-optical erasable las2r recording materials are also
known in the art. For example, see U.S. patent 4,493,887
to Peeters et al. Improved sensitivity is obtalned in
these media at the expense of extra layers which increase
complexity and cost. This increased sensitivity is not
necessary for a card format
Disclosure of Invention
It is the object of the present invention to
devise a wallet-size plastic data card containing two
optical data strips and a system for sequential recording
transaction data on the data card with a laser where the
data on the card optically contrasts with the surrounding
unrecorded field. It is also an object of the invention
to perfor~ related sequential laser recording of trans-
actions and everlts related to the fields of insurance,
personal medical records, personal information, banking
and related data records.
It is a further object of the invention to
devise a wallet-size card, containing a laser recordable
strip, that meets the IS0 dimensions for plastic credit
cards, has a capacity of at least 250,000 bits, can
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recorcl data ~t thousclnds of hit~ per second and contains pre--
recorded is~formation sueh as relerence posi~ion on the strip.
The above objects have been met with an cptically read,
reflective data card having one media portion with pre-recorded
programs or data and another media portion being in-situ
recordable and substantially blank.
In accord with the present invention the media portion
havin~ pre-recorded programs or data is always a non-erasable
strip. This strip may be either a reflective DRAW strip of the
non-erasable type or may be a read-only optical memory (ROOM)
strip. On the other hand, the media portion serving as the
temporaryr scratchpad or cache memory is a reflective DRAW strip
of the erasable type.
Thus, the invention may be summarized as an optical data
card comprising, a card substrate having opposed sides and a
length equal to or exceeding a widtht a first strip of erasable
optical recording material affixed to said card substrate, said
first strip being in-situ laser recordable and being substantially
blank, and a second strip of optical data storage material affixed
to said card substrate, said second strip having permanently pre-
recorded programs or data thereon.
One of the chief advantages of the present invention is
the high information capacity of laser recording media strips,
either of the erasable or non-erasable type. By using a pre-
recorded strip for permanent data and an in-situ recordable strip
for temporary storage, a single card provides for computa~ional
and data base needs. Typically, high resolution laser recording
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materials record spots of altered reflectivity optically
contrasting wi-th the surrounding reflective field and having
dimensions less thall 25 microns. A high capacity laser recording
material strip enab:les a financial data card or other types of
data cards to carry the equivalent of scores of pages of text,
more than ample for most applications. The transaction card of
the present invention is suitable for accumulating sequentially
recorded data involving financial transactions, insurance
~r~nsactions, medical information and events, and personal
information and identif:ication.
Brief Description of Drawings
Fi~. 1 is a plan view of one side of a data
card in accord with the present invention.
Fig. 2 is a partial side sectional view taken
along lines 2-2 in Fig. 1.
Fig. 3 is a plan view of one side of an
alternate embodiment of a data card in accord with the
present invention.
Fig. 4 is a partial side sectional view taken
along lines 4-4 in Fig. 3.
Fig. 5 is a detail of laser writing on a
portion of the laser recording strip illustrated by
dashed lines in Fig. 1.
Fig. 6 is a plan view of an apparatus for
reading and writing on the optical recording media strip
illustrated in Fig. 1.
Fig. 7 is a plan view of an apparatus for
reading and writing on the optical recording media strip
illustrated in Fig. 3.
Best Mode for Carrying Out the Invention
With reference to Figs. 1 and 2, a data card 11
is illustrated having a size common to most credit cards.
The width dimension of such a card is approximately 54 mm
and the length dimension is approximately 85 mm. These
dimensions are not critical, but preferred because such a
size easily fits into a wallet and has historically been
adopted as a convenient size for automatic teller ma-
chines and the like. The card's base 13 is a dielectric,
usually a plastic material such as polyvinyl chloride or
similar material. Polycarbonate plastic is preferred.
The surface finish of the base should have low specular
reflectivity, preferably less than 10%. Base 13 carries
strip 15. I'he strip is about 15 millimeters wide and
extends the length of the ~ard. Alternatively, the strip
may have other sizes and orientations. The strip is
relatively thin, approximately 100-500 microns, although
this is not critical. The strip may be applied to the
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card by any convenient method which achieves flatness.
The strip is adhered to the card with an adhesive and
covered by a transparent laminating sheet 19 which serves
to keep strip 15 flat, as well as protecting the strip
from dust and scratches. Sheet 19 is a thin, transparent
plastic sheet laminating material or a coating, such as a
transparent lacquer. The material is preferably made of
polycarbonate plastic.
The opposite side of base 13 may have user
identification indicia embossed on the surface of the
card. Other indicia such as card expiration data, card
number and the like may be optionally prcvided.
The high resolution laser recording material
which forms strip 15 may be any of the reflective record-
ing material which have been developed for use as directread-after-write (DRAW) optical disks, so long as the
materials can ~e formed on thin substrates. An advantage
of reflective materials over transmissive materials is
that the read/write equipment is all on one side of the
card and automatic focus is easier. For example, the
high resolution material described in U.S. patent
4,230,939 issued to de Bont, et al. teaches a thin metal-
lic recording :Layer of reflective metals such as Bi, Te,
Ind, Sn, Cu , Al, Pt, Au, Rh, As, Sb, Ge, Se, Ga. Mate-
rials which are preferred are those having high re-
flectivity and low melting point, particularly Cd, Sn,
Tl, Ind, Bi and amalgams. Suspensions of reflective
metal particles in organic colloids also form low melting
temperature laser recording media. Silver is one such
metal. Typical re~ording media are described in U.S.
patents Nos. 4,314,260, 4,298,684, 4,278,758, 4,278,758,
4,278,756 and 4,269,917, all assigned to the assignee of
the present invention. The laser recording material
which is selected should be compatible with the laser
which is used for writing on it. Some materials are more
sensitive than others at certain wavelengths. ~ood sen-
sitivity to infrared light is preferred because infrared
is affected least by scratches and dirt on the trans-
~B320S
parent laminating sheet. The selected recording materialshould have a favorable signal-to-noise ratio and form
high contrast data bits with the read/write system with
which it is used. The material should not lose data when
sub~ected to temperatures of about 122~F (50C) for long
periods. The material should also be capable of re-
cording at speeds of at least several thousand bits/sec.
This generally precludes the use of materials that
require long heating times or that rely on slow chemical
reactions in the presence of heat, which may permit
recording of only a few bits/sec. A large number of
highly reflective laser recording materials have been
used for optical data disk applications. Data is
recorded by forming spots in the surrounding field of the
reflective layer itself, thereby altering the
reflecti~ity in the data spot. Data is read by detecting
the optical reflective contrast between the surrounding
reflective field of unrecorded areas and the recorded
spots. Spot reflectivity of less than half the
reflectivity of the surrounding field produces a contrast
ratio of at least two to one, which is sufficient con-
trast for reading. Greater contrast is preferred.
j Reflectivity of the strip field of about 50% is preferred
with reflectivity of a spot in the reflective field being
less than 10~, thus creating a contrast ratio of greater
than five to one. Another laser recording material eis
Drexon material, a trademark of Drexler Technology
Corporation. The material is similar to that described
in U.S. patent 4,284,716, assigned to the assignee of the
present invention. While Drexon material is non-eras-
able, other reflective DRAW materials, which are eras-
able, may be used. An example of an erasable DRA~
material is shown in U.S. patent 4,527,173 to Gupta et
al. Also, Magneto-
optical and amorphous to crystalline phase change
I erasable D~AW later recording materials have been ~nown
I in the art for a decade. Alternatively, data may also be
I recorded by increasing the reflectivity of the strip.
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For example, the recording laser can melt a field of dull
microscopic spikes on the strip to create fla~ shiny
spots. This method is described in SPIE, Vol. 329,
Optlcal Disk Technology (1982), p. 202. A spot re-
flectivity of more than twice the surrounding spiked
field reflectivity produces a contrast ratio of at least
two to one, whlch is suf~icient contrast for reading.
An important consideration is that the first
strip 15 be in-situ laser recordable. This same require-
ment is not applicable, although permissible, for thesecond strip 17, having similar dimensions to first strip
15 and parallel thereto. The second strip is optical
data storage media and may be read-only-optical-media
(ROOM) of the type made in accord with U.S. patent
4,304,848 to E. Bouldin and J. Drexler, assigned to the
assignee of the present invention. The important con-
sideration for the second optical data strip 17 is that
it contain pre-recorded programs or data thereon. Such a
strip should be able to record spots down to about 10
microns or smaller in size. The second strip may also be
Drexon material, or material similar to the first strip
as ~ong as it contains pre-recorded programs or data.
The purpose of the first strip is to act as
tem~orary data storage. The ~irst striP ;s always
an erasable DRAW reflective strip which may be reused
upon erasing. While the first strip would generally not
include a large percentage of pre-recorded material, it
may contain some pre-recorded material, such as tracking
information, so long as there is sufficient room on the
card for lasr recording of user data.
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Example 1
The first strip may be a D~A~ erasable strip,
while the second strip may be a DRAW non-erasable strip
having pre-recorded proqrams or data. The erasable strip
could be made in accord with U.S. patent 4,527,173 while
the non-erasable str~p could be Drexon material.
~xample 2
The first strip could be a D~AW erasable strip,
as in Example 1, but the second strip is a read-only-
optical-memory strip having pre-recorded programs or
data.
The first strip could be a DRAW erasable strip,
having some pre-recorded information, but having room for
temporary storage. The second strip is a read-only-
optical-memory strip having pre-recorded information.
In each example, the first strip has room for
temporary storage of intermediate results which may or
may not be permanently written. The second strip has
permanent programs and data, such as database infcrmation
which may be acted upon by a computer to create the
temporary storage information placed on the first strip.
With reference to Figs. 3 and 4, a card 21 is
shown, having a plastic base 23, similar to base 13 in
Fig. 1. The card 21 has opposed first and second strips
25 and 27 adhered thereto with transparent laminating
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sheet ~9 covering the base, as well as the strip 25,
holding it securely in place. ~he card of Figs. 3 and 4
is essentially the same as the card of Figs. 1 and 2
except for the manner in which he two strips are
arranged. In Fig. 1, the strips are on the same side of
the card so that all reading and writing transducers can
be located on the same side of the card, while in Fig. 3,
optical transducers must be located on opposite sides of
the card for reading and writing thereon~
With reference to Fig. 5, a magnified view
of laser writing on the laser recording material strip 15
may be seen. The dashed line 33~ corresponds to the
dashed line 33 in Fig. 1. The oblong spots 35 are
aligned in a path and have generally similar dimensions.
The spots are generally circular or oval in shape with
the axis of the oval perpendicular to the lengthwise
dimension of the strip. A second group of spots 37 is
shown aligned in a second path. The spots 37 have
similar dimensions to the spots 35. The spacing between
paths is not critical, except that the optics of the
readback system should be able to easily distinguish
between paths.
Presently, in optical disk technology, tracks
which are separated by only a few microns may be re-
solved. The spacing and pattern of the spots along eachpath is selected for easy decoding. For example, oval
spots of the type shown can be clustered and spaced in
accord with self-clocking bar codes. If variations in
the dimensions of a spot are required, such dimensions
can be achieved by clustering spots, such as the double
spot 39. Such variations are used in the ETAB bar code
which i5 described in U.S~ patent 4,245,152. While the
American Banker's Association has not yet adopted any
particular code, the strip material is such that many
3 machine and eye readable codes can be accommodated. Some
optical codes such as the Universal Product Code are both
machine and eye readable. Such codes could also be
accommodated, although a great deal more laser writing
1~83Z [)5
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would be required than with circular or oval spots, and a
much lower information density would be achieved. The
spots illustrated in Fig. 5 ~ypically have recommended
sizes of approximately 5 microns by 20 microns, or 2
microns by 8 microns or circular spots 3 microns or 10
microns in diameter. Generally, the smallest dimension
of a spot should be less than 50 microns. In the pre-
ferred embodiment the largest dimension would also be
less than 50 microns. Of course, to offset lower densi-
ties from larger spots, the size of the strip 15 could beexpanded to the point where it covers a large extent of
the card. In ~ig. 1, the laser recording strip 15 could
completely cover a single side of the card. A minimum
information capacity of 250,000 bits is indicated and a
storage capacity of over one million bits is preferable.
In Fig. 6, a side view of the lengthwise dimen-
sion of a card 41 is shown. The card is usually received
in a movable holder 42 which brings the card into the
beam trajectory. A laser light source 43, preferably a
pulsed semiconductor laser of near infrared wavelength
emits a beam 45 which passes through collimating and
focusing optics 47. The beam is sampled by a beam
splitter 49 which transmits a portion of the beam through
a focusing lens 51 to a photodetector 53. The detector
53 confirms laser writing and is not essential. The beam
is then directed to a first servo controlled mirror 55
which is mounted for rotation along the axis 57 in the
direction indicated by the arrows A. The purpose of the
mirror 55 is to find the lateral edges of the laser
recording material in a coarse mode of operation and then
in a fine mode of operation identify data paths which
exist predetermined distances from the edges.
~ rom mirror 55, the beam is directed toward
mirror 61~ This mirror is mounted for rotation at pivot
63. The purpose of mirror 55 is for fine control of
motion of the beam along the length of the card. Coarse
control of the lengthwise position of the card relative
to the beam is achieved by motion of movable holder 42.
332~
In Fig. 7, a mirror image optical system may be used to
read the back slde of a card. A laser light source 43'
emits a bea~ 45', passing through collimating and
focusing optics 47'. Optical components 49', 51', 53',
55', 57', 59', 61', 63l, 65', 67', 69' all correspond in
function and performance to the unprimed components of
the same number. The meth~d o~ support of the card in
Fig. 7 is slightly different since it is not possible to
use a carriage 52. Support is shown by means of idlers
42' which allow the card to be supported on both sides
and moved by rotation of the idlers which are driven in
synchronism by a ~elt or wheel.
The position of the holder may be established
by a linear motor adjusted by a closed loop position
servo system of the type used in magnetic disk drives.
During its manufacture one strip of the card is pre-
recorded with a preinscribed pattern containing servo
tracks, timing marks, program instructions, and related
functions, while the other strip may have pre-recorded
portions, but must have room for user laser writing. The
positioning marks can be used as a reference for the
laser recordirlg system to record or read data at partic-
ular locations. Each of the various industries, that is,
financial, insurance, medical, and personal, has formats
specific to its particular needs. Formatting may be done
using laser recording or surface molding of the servo
tracksl having marks, programming and related functions.
Dil, in U.S. patent 4,209,804 teaches a type of surface
molding. Reference position information may be pre-
recorded on the card so that position error signals may
be generated and used as feedback in motor control. Upon
readin~ one data path, the mirror 55 is slightly rotated.
The motor moves holder 41 lengthwise so that the path can
be read, and so on. Light scattered and reflected from
the spots contrasts with the surrounding field where no
spots exist. The beam should deliver sufficient laser
pulse energy to the surface of the recording material to
create spots. Typically, 5-20 milliwatts is required,
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depending on the recording material. A 20 milliwatt
semiconductor laser, focussed to a five micron beam size,
records at temperatures of about 200 C and is
capable of creating spots in less than 25 microseconds.
The wavelength of the laser should be compatible with the
recording material. In the read mode, power is lowered
to about 5% of the record power.
Optical contrast between a spot and surrounding
field are detected by light detector 65 which may be a
photodiode. L1ght is focussed onto detector 65 by beam
splitter 67 and focusing lens 69. Servo motors, not
shown, control the positions of the mirrors and drive the
mirrors in accord with instructions received ~rom control
circuits, as well as from feedback devices. The detector
65 produces electrical signals corresponding to spots.
These signals are processed and recorded for subsequent
display as useful information r~garding the transaction
recorded on the card.
In operation, the card of the present invention
is used to record sequentially accumulated data, as medi-
cal records, insurance records, personal information, or
financial transactions using a strip with pre-recorded
information. ~or example, it could be used just like a
passbook. First the card is read to determine previously
recorded information. Next, a user enters his
transaction on a financial txansaction or medical infor-
mation recorder. Such recorder then causes data to be
written on the f~rst strip by means of the laser. The
data represents a passbook entry with a new account
status. A computer may use the temporary storage strip
to record intermediate computations or data. Operating
in this mode, a user may use the card of the present
invention in free standing financial transactions or
medical information machines in isolated locations.
