Prerecorded dual strip data storage card

A data storage card having spaced apart data strips. The card is wallet-size and preferably the strips run parallel to the lengthwise dimension of the card. One strip is made of a high capacity reflective read-only optical memory (ROOM) material. The other strip is a magnetic recording material. The high capacity ROOM strip may be made of a laser recorded material or it may be made of a material which is prerecorded using a photographic process. The two strips store complementary data in database applications.

TECHNICAL FIELD 
The invention relates to data storage cards and more particularly to data 
storage cards which can be used to store information related to insurance, 
personal medical histories and the like. 
BACKGROUND ART 
In U.S. Pat. No. 4,360,728, Drexler describes a data card having a laser 
recording, direct-read-after-write (DRAW) strip, alongside a magnetic 
strip, the two strips working in cooperation. Maurer et al. in U.S. Pat. 
No. 4,467,209 discloses 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. Neither of these cards is sufficient since both permit 
alterations or additions to be made on either strip after the cards have 
been produced. The ability to make alterations and additions on the 
magnetic strip is desirable. But it is not necessarily a desirable 
characteristic for the data storage strip. This capability means increased 
cost. It is one of the objects of the present invention to reduce costs in 
the production of data cards. Furthermore, there are data card uses for 
which it is best not to permit alterations or additions after entries into 
data storage. 
Dil, in U.S. Pat. No. 4,209,804, teaches a reflective 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 of optical phase shift effects. Since 
the preformed grooves are at an optical phase depth of 95.degree. to 
140.degree., the reading laser must be of the precise wavelength 
corresponding to the groove depth. The information area has a width of 
approximately 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 surface to a protective laminating 
material with an adhesive without introducing a varying phase shift across 
the surface. It is also impractical to melt large holes since a large lip 
would be formed around the hole causing a great 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 wavelength 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. Pat. No. 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 permanently 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 175.degree. F. 
and an additional 5 milliseconds above 175.degree. F. 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. 
Various recording media have been developed for use on a rotating disk 
format. Because the disk is spinning rapidly, short laser pulse times (on 
the order of 500 nanoseconds) are necessary to confine the heating to 
small spots. The media have been developed to increase the sensitivity to 
the beam by varying the parameter of media absorptivity. Spong in U.S. 
Pat. Nos. 4,190,843 and 4,305,081 puts an absorptive dye layer over a 
reflective aluminum layer. Spots are recorded by ablation of the dye layer 
exposing the underlying reflective layer. Bell in U.S. Pat. No. 4,300,143, 
teaches a similar technique. Bartolini in U.S. Pat. No. 4,313,188 adds a 
protective layer between the dye layer and the reflective layer. Wilkinson 
in U.S. Pat. No. 4,345,261 uses a light absorptive silica 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. Pat. No. 
4,202,491 uses a fluorescent ink layer on which data spots emit infrared 
radiation. Magneto-optical erasable laser recording materials are also 
known in the art. For example, see U.S. Pat. No. 4,493,887 to Peeters et 
al. Improved sensitivity is obtained in these media at the expense of 
extra layers which increase complexity and cost. This increased 
sensitivity is not necessary for a card format. 
Bouldin et al. discloses one suitable method for photographically 
replicating information on the optical data storage medium of the present 
invention. The information is copied when actinic radiation is shown 
through transmissive areas of a master onto a silverhalide emulsion 
photosensitive medium. The medium is then developed. A laser is used to 
read the changes in reflectivity resulting from the process. 
In the field of information storage there is sometimes a need to use two 
complementary databases. An object of the present invention is to devise a 
data card suitable for use with such databases. 
DISCLOSURE OF THE INVENTION 
The above objects have been met with a prerecorded read-only optical memory 
(ROOM) strip used in conjunction with a magnetic strip preferably parallel 
to the lengthwise dimension of a wallet-size card. The prerecorded ROOM 
strip comprises a high capacity, reflective data storage material. The 
strip may be made of a laser recording material or one which is 
photographically processed. The second strip consists of a magnetic 
recording material which is parallel to, but spaced apart from, the ROOM 
strip. 
One of the advantages of the present invention is the high information 
capacity of the ROOM strip. By using the replication method described in 
U.S. Pat. No. 4,304,848, such a strip is able to contain prerecorded data 
spots down to ten microns or smaller in size. Large databases may be 
prerecorded on such an optical strip. The adjacent magnetic strip may 
contain other data which is either prerecorded or recorded by a user and 
may utilize the optically stored information for initial data, reference 
data or other stored data. The magnetic data is erasable, but the 
optically prerecorded data is not.

BEST MODE FOR CARRYING OUT THE INVENTION 
With reference to FIGS. 1 and 2, a data storage card 11 is illustrated 
having a size common to most credit cards. The exact size is not critical 
but the card should be able to fit easily into a wallet. The card's base 
13 is a dielectric, usually a plastic material such as polyvinyl chloride 
or similar material. The surface finish of the base should have low 
specular reflectivity, preferably less than 10%. Base 13 has a pair of 
shallow grooves which carry first and second strips 15 and 17, 
respectively. The strips are each about 15 millimeters wide and extend the 
length of the card. Alternatively, the strips may have other sizes and 
orientations. The strips are relatively thin, approximately 100-500 
microns, although this is not critical. A read-only optical memory (ROOM) 
strip 15 is typically 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. An automated method for installing magnetic strips 17 is 
described in U.S. Pat. No. 4,231,828. 
The opposite side of base 13 may have user identification indicia embossed 
on the surface of the card. Other indicia such as insurance policy 
expiration date, policy number and the like may be optionally provided. 
The ROOM strip 15 is a high capacity, reflective data storage material. The 
capacity should be such that the strip can act as a data base holding the 
equivalent to scores of pages of text. The data is prerecorded onto the 
strip. Methods are known whereby data storage media may be prerecorded 
with information and then read by comparing areas of low reflectivity and 
areas of high reflectivity. To take advantage of the resulting cost 
reductions, the method which is chosen should be one which allows 
reproduction of data from a master. For example, Bouldin et al. in U.S. 
Pat. No. 4,304,848 permits reproduction of data from a master transmissive 
optical data storage medium. 
With reference to FIG. 5, a magnified view of a read-only optical memory 
strip 34, taken from within dashed line 33 of FIG. 1, may be seen. The 
strip 34 is prerecorded with data by use of a photographic method as 
taught by Bouldin et al. Actinic radiation is shone through transmissive 
areas in a master data storage medium, not shown, onto the ROOM strip 34. 
The strip 34 is made up of a silver-halide emulsion 38 on a substrate 39, 
which is usually transparent glass or plastic. The silver-halide emulsion 
38 is then chemically developed black. Next, the developed medium is 
fogged to create a latent image layer of silver precipitating nuclei. 
Finally, the fogged medium is placed in a monobath for partial chemical 
development and substantial physical development. The resulting product 
displays areas of low reflectivity, which correspond to the transmissive 
areas of the master. In FIG. 5 these areas of low reflectivity are 
represented by black areas 35a, 35b and 35c. The areas of the strip 34 
which do not correspond to the transmissive areas of the master contain 
metallic silver, represented by the clustered dots 37. The black areas 
35a, 35b and 35c of the strip 34 have reflectivities typically under 5% 
while the remaining areas have reflectivities typically greater than 25%. 
Thus, the reflective contrast ratio usually exceeds 5:1. The ratio should 
be at least 3:1. 
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 sheet 29 
covering the base, as well as the strip 25, holding it securely in place. 
The card of FIGS. 3 and 4 is essentially the same as the card of FIGS. 1 
and 2 except for the manner in which the two strips are arranged. On FIG. 
1, the strips are on the same side of the card so that all reading 
transducers can be located on the same side of the card, while in FIG. 3, 
reading transducers must be located on opposite sides of the card. 
Data is encoded onto a ROOM strip by alternating low reflectivity and high 
reflectivity areas along a track on the strip. Presently, in optical disk 
technology, tracks which are separated by only a few microns may be 
resolved. The spacing and pattern of the low reflectivity areas along each 
track are selected for easy decoding. For example, the black areas 35a, 
35b and 35c of FIG. 5 can be clustered and spaced in accord with 
self-clocking bar codes. The spacing between tracks is not critical, 
except that the optics of the readback system should be able to easily 
distinguish between paths. 
In FIG. 6, a side view of the lengthwise dimension of a card 44 is shown. 
The card is usually received in a movable holder 42 which brings the card 
into a beam trajectory. A laser light source 43, preferably a 
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 
output 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 ROOM strip in a coarse mode of operation 
and then in a fine mode of operation identify data tracks which exist 
predetermined distances from the edges. 
From mirror 55, the beam is directed toward mirror 61. This mirror is 
mounted for rotation at pivot 63. The purpose of the mirror 61 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. 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. Reference position information may be 
prerecorded on the card. Upon reading one data track the mirror 55 is 
slightly rotated. The motor moves holder 42 lengthwise so that the next 
track can be read, and so on. Light scattered and reflected from the black 
areas 35a, 35b and 35c of FIG. 5 contrasts with the surrounding field 
where no prerecorded areas exist. 
Differences in reflectivity between a black area and surrounding material 
are detected by light detector 65 which may be a photodiode. Light 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 from control circuits as well 
as from feedback devices. The detector 65 produces electrical signals 
corresponding to black areas. These signals are processed and recorded for 
subsequent display as useful information regarding the prerecorded data on 
the card. FIG. 6 does not show the magnetic transducer used for reading 
the magnetic strip, but such transducers and the codes for magnetic strips 
are well known. 
In operation, the data storage card of the present invention could be used 
to store databases. The ROOM strip can be encoded with an assemblage of 
information, such as an insurance policy or a library index. Then the 
magnetic strip may be used to hold information separate from, but related 
to, that data held on the ROOM strip. Or the magnetic strip may be used to 
temporarily store data which is also contained on the optical strip. Use 
of the magnetic strip is intended to complement or rely upon the optical 
strip or to be used to fill shortterm storage requirements.