Method of reading electrical information and information carrying member for use in the method

A method of reading electrical information, which comprises arranging electric field-generating means having a pulse oscillator and detection means of detecting a potential in the electric field to form an electrostatic coupling space and/or a latent electrostatic coupling space where the and the detection means can sense a change in the electric field as a change of potential passing an information carrying member formed by covering an electrically conductive member having a form expressing information with an electrically nonconductive material through the electrostatic coupling space or the latent electrostatic coupling space, thereby to detect the information expressed by the form of the electrically conductive member, and information carrying member for use in the method.

FIELD OF THE INVENTION 
This invention relates to a method of reading electrical information 
carrying which comprises passing an information member, which is formed by 
covering an electrically conductive member having a form expressing 
information with an electrically nonconductive material, through an 
electrostatic coupling space and/or a latent electrostatic coupling space 
and detecting the form of the electrically conductive member, and an 
information carrying member for use in the method. 
DESCRIPTION OF RELATED ART 
For a debit card, a credit card, a bank card, an I.D. card, a driver's 
license, a ticket, an admission ticket, a membership card, a card for 
securities, certificates, and the like, a variety of proposals have been 
made hitherto in order to improve the means of preventing alteration and 
falsification thereof, to improve means of recording and reading them for 
identification or to improve the resistance of the stored information from 
damage. These proposals are directed to a single use or combined use of 
means of processing a paper or plastic substrate surface such as a 
printing, engraving, embossing, laser, discharging, laminating or vapor 
deposition means, a functional material such as a magnetic, electrically 
conductive, photosensitive, heat-sensitive, foaming or light-emitting 
material and a detecting means which works depending upon function. 
In the recordal of information for identification, it is general practice 
to compare a visible information such as a name, a date of birth, a 
signature, a card number or a photograph of a face with a written 
invisible information, a signature written in the presence of a comparer 
or a face. A magnetic recording method has been heretofore widely used as 
a simplest means of writing invisible information. 
However, magnetically written information has a risk of being erased by an 
external high magnetic field. Further, since the magnetic recording method 
has become popular in recent years, there is a risk of magnetically 
written information being copied, altered or falsified. In order to 
prevent such risks, various proposals have been made, such as increasing 
of the coercive force of a magnetic film per se, patterning of an 
information-recorded portion, changing of a decoding rule, and the like. 
However, the magnetic recording method involves a risk of abuse due to its 
inherent possibility that information can be rewritten without destructing 
an information-written card, etc. 
There is another proposal for a method for storing invisible information, 
in which an integrated chip (IC) is embedded in the card and information 
is written in the IC memory. However, this method is expensive, and its 
use is hence limited. 
Further, information to be provided to a card, a certificate, etc., is 
classified into constant information and individual information. The 
constant information means information which is replicated in a large 
amount by processing means typified, e.g. by printing, and examples of the 
constant information include a picture, a pattern, a mark, bar code source 
masking, etc. The individual information means that which is formed by 
providing an individual recording medium with a separate information, 
e.g., by an embossing, magnetic-recording, or printing method. Examples 
thereof include embossed letters, coating or numbering on a magnetic film, 
and the like. 
It is only a magnetic recording method that is substantially available for 
automatizable and less expensive means of writing invisible and individual 
information. However, this method has a large risk of being altered and 
falsified. 
As a substitute means for the magnetic recording method, JP,A 49-60835, 
corresponding to U.S. Pat. No. 3,699,311, discloses a method using a 
combination of a card having encoded information bits with a decoder. In 
this combination, the decoder has a transmitter plate and a detector 
plate, and other plate is provided inside the card so as to form a 
condenser together with the transmitter plate and the detector plate. And, 
the presence or absence of information bits is determined depending upon 
connection or disconnection between the plates. In this method, the number 
of information bits or the location of information is fixed, and a form of 
information cannot always be determined. In particular, it is impossible 
to detect information which is formed depending upon a length, area or 
form of the plate, and the amount of information stored in the card is 
limited. 
SUMMARY OF THE INVENTION 
It is an object of this invention to provide a method of reading electrical 
information, which can provide, at a low cost and with ease, invisible and 
individual information having a large volume of data and being almost free 
from a risk of alteration and falsification, and which can be easily 
automatized, and an information carrying member for use in the method. 
It is another object of this invention to provide a method of reading 
electrical information, for which an electrically conductive member having 
high strength against an environmental change and having a form expressing 
information can be easily formed, and an information member for use in the 
method. 
It is further another object of this invention to provide a method of 
reading electrical information, which permits reading electrical 
individual information at a real time, and an information carrying member 
for use in the method. 
Further, it is another object of this invention to provide a method of 
reading electrical information, which is capable of reading 
two-dimensional information by only unidimensionally moving an information 
member having the two-dimensional information or by fixing the information 
member, and an information member for use in the method. 
The "electrically conductive member having a form expressing information" 
in this invention means an electrically conductive member formed into, for 
example, a pattern, etc., of a plurality of bars, etc. 
According to this invention, there is provided a method of reading 
electrical information, which comprises arranging electric 
field-generating means having a pulse oscillator and detection means of 
detecting a potential in the electric field to form an electrostatic 
coupling space and/or a latent electrostatic coupling space where the 
electric field-generating means and the detection means mutually interfere 
with each other due to electrostatic coupling, and passing an information 
member formed by covering an electrically conductive member having a form 
expressive information with an electrically nonconductive material through 
the electrostatic coupling space or the latent electrostatic coupling 
space, thereby to detect the information according to the form of the 
electrically conductive member. 
Further, according to this invention, there is provided an information 
carrying member for use in the above method, which is formed by covering 
an electrically conductive member having a form expressing information 
with an electrically nonconductive material.

DETAILED DESCRIPTION OF THE INVENTION 
The method of reading electrical information, provided by this invention, 
include the following three modes. 
In the first method of a means of generating an electric field and means of 
detecting an electric potential are arranged to form an electrostatic 
coupling space, and an information carrying member is allowed to pass 
through the electrostatic coupling space to block a pulse from the means 
of generating an electric field by an electrostatic shielding effect, 
whereby information expressed by the form of the electrically conductive 
member of the information carrying member is detected. 
In the second method a means of generating an electric field and means of 
detecting an electric potential are arranged to form an electrostatic 
coupling space and a latent electrostatic coupling space, and an 
information carrying member is allowed to pass through the latent 
electrostatic coupling space to block a pulse from the means of generating 
an electric field by an electrostatic shielding effect, whereby 
information expressed by the form of the electrically conductive member of 
the information carrying member is detected. 
In the third method, a means of generating an electric field and means of 
detecting an electric potential are arranged to form a latent 
electrostatic coupling space, and an information carrying member is 
allowed to pass through the latent electrostatic coupling space to 
transmit an electric potential from the means of generating an electric 
field to the means of detecting an electric potential by an electrostatic 
induction effect, whereby information expressed by the form of the 
electrically conductive member of the information carrying member is 
detected. 
In the above first method, it is necessary to substantially ground the 
electrically conductive member of the information carrying member through 
electrostatic coupling by providing at least one of the means of 
generating an electric field and the means of detecting an electric 
potential with a grounding plate in parallel with and contiguously to the 
information carrying member which is passing the electrostatic coupling 
space. 
Further, in the above first method, it is preferable, in view of increasing 
detection sensitivity, to substantially ground the electrically conductive 
member by providing the information carrying member with a connection 
member formed of an electrically conductive material thereby to connect, 
e.g. bars of the electrically conductive member with the connection 
member, providing the information carrying member with an electrostatic 
coupling space-forming member, which forms an electrostatic coupling space 
together with the grounding plate, thereby to connect the connection 
member to the electrostatic coupling space-forming member, and 
electrostatically coupling the grounding plate with the electrostatic 
coupling space-forming member as shown in FIG. 19. 
In the above first method, it is preferable, in view of increasing 
detection sensitivity for information identification, to provide at least 
one of the means of generating an electric field and the means of 
detecting an electric potential with a guard plate which prevents 
formation of an electrostatic coupling space other than the electrostatic 
coupling space for detection. 
In the second method, it is preferable to provide a grounding plate in 
parallel with and contiguously to the electrically conductive member of 
the information carrying member in order to substantially ground the 
electrically conductive member easily. 
In the second method, it is preferable, in view of increasing detection 
sensitivity, to provide at least one of the means of generating an 
electric field and the means of detecting an electric potential with a 
guard plate in order to prevent formation of an electrostatic coupling 
space other than the electrostatic coupling space for detection. 
In the third method, it is preferable, in view of increasing detection 
sensitivity, to provide at least one of the means of generating an 
electric field and the means of detecting an electric potential with a 
guard plate in order to prevent formation of an electrostatic coupling 
space between the means of generating an electric field and the means of 
detecting an electric potential. 
In the third method, the means of generating an electric field may be 
arranged toward one surface of the information carrying member, and the 
means of detecting an electric potential may be arranged toward the other 
surface of the information carrying member. 
Examples of the electrically conductive member in this invention are an 
electrically conductive film, electrically conductive fibers, and the 
like. 
This invention will be explained more specifically below by reference to 
drawings, in which an electrically conductive film in a various form is 
used as a typical example of the electrically conductive member. 
FIGS. 1 and 2 are block diagrams of an apparatus used for the first method 
of reading information, in which 1 indicates a card having a sandwich 
structure formed by covering a patterned electrically conductive film with 
an electrically nonconductive material, 7 indicates a pulse oscillator, 8 
indicates an amplifier for amplification of a pulse from the pulse 
oscillator, 2 indicates a generator plate to generate an electric field 
according to the amplified pulse, 3 indicates a detector plate to detect 
the electric field, 9 indicates a circuit for detection of the potential 
of the detector plate 3 and filtering, 10 indicates a circuit for 
synchronization between the pulse from the oscillator 7 and the detected 
pulse and waveform shaping, and 11 indicates a circuit for decoding the 
detected and waveform-shaped pulse and outputting. Further, 5 is a 
grounding plate having a through hole 12. And, the generator plate 2 is 
disposed above the through hole 12, the detector plate 3 is disposed below 
the through hole 12, and these two plates are coaxially disposed such that 
they are electrically not in contact with the grounding plate 5. The 
positional relationship of these two plates may be changed. Numeral 6 is a 
guard plate to limit broadening of potential-detecting space for the 
detector plate to an end portion of the detector plate, and the guard 
plate is disposed such that it laterally covers the detector plate through 
an insulating layer 4. The grounding plate having the through hole can 
substantially work also as a guard plate, and it is therefore not 
necessarily required to provide the detector plate with the guard plate. 
When the detector plate or the generator plate is provided with a guard 
plate, the grounding plate 5 having a through hole is not necessarily 
required, and a grounding plate may be disposed on the lateral side of the 
card 1 along the moving direction of the card 1, whereby an electrically 
conductive film within the card can be reduced to a grounded potential due 
to electrostatic coupling. Due to electrostatic coupling, a mutual 
interference space is formed between an end surface 13 of the detector 
plate and an end surface 14 of the generator plate. The space between the 
end surfaces 13 and 14 is referred to as an electrostatic coupling space 
hereinafter. 
FIG. 2 shows an embodiment where each of grounding plates 5 and 15 having a 
through hole 12 is disposed between two plates. A generator plate and a 
detector plate are disposed coaxially. End surfaces 13 and 14 of these two 
plates are not necessarily required to be disposed at the same levels as 
those of the grounding plates 5 and 15. 
FIGS. 3 to 7 each explain an apparatus used for the second method of 
reading information. 
In FIG. 3, 16 indicates a grounding plate having a hole 17 below a 
generator plate 2 and a detector plate 3 which are disposed in parallel 
with an electrically conductive film of a card. The generator plate 2 has 
end surfaces 14 and 19, and the detector plate 3 has end surfaces 13 and 
18. The end surface 14 and 13 are formed to be nearly in parallel with 
each other, and the end surfaces 19 and 18 are formed to be nearly at 
right angles with the end surfaces 14 and 13 and nearly at the same level. 
Numeral 20 indicates a moving direction of the card. 
FIGS. 4 and 5 schematically show functions of an apparatus shown in FIG. 3. 
FIG. 4 shows an embodiment where an electrically conductive film 21 is not 
positioned below the end surfaces 19 and 18 of the above plates 2 and 3. 
Numerals 22 and 23 indicate an electrically nonconductive film covering 
the electrically conductive film 21. In this state, the end surface 19 of 
the generator plate 2 and the end surface 18 of the detector plate 3 are 
electrostatically coupled. 
FIG. 5 shows an embodiment where the electrically conductive film 21 is 
positioned below the end surfaces 19 and 18 of the above plates 2 and 3. 
Since a grounding plate 16 and the electrically conductive film 21 are 
electrostatically coupled with each other, the electrically conductive 
film 21 is reduced substantially to a grounded potential. Due to the 
presence of the electrically conductive film 21 having a grounded 
potential, the end surfaces 19 and 18 of the above plates are 
electrostatically coupled with each other through the electrically 
conductive film 21. As a result, the potentials of these two plates are 
reduced nearly to a grounded one, and the electrostatic coupling between 
the end surfaces 14 and 13 of these two plates is electrostatically 
reduced and changed to an electrostatically shielded state. For this 
reason, a space formed by the end surfaces 19 and 18 is referred to as a 
latent electrostatic coupling space in the present invention. 
FIG. 6 is a schematic view of an apparatus including a partial cross 
sectional view of one embodiment in which a generator plate 2, a detector 
plate 3 and a guard plate 6 to control the position of the electrostatic 
coupling space formed by these generator and detector plates are 
concentrically arranged. This arrangement of the plates 2 and 3 and the 
guard plate 6 makes it possible to remove directional dependency of 
detection sensitivity. In this embodiment, it is necessary to dispose a 
grounding plate 24 such that it is never arranged within the electrostatic 
coupling space and the latent electrostatic coupling space. 
FIG. 7 shows an embodiment where a guard plate 6 is cylindrically arranged 
around a cylindrical generator plate 2 and a cylindrical detector plate 3, 
and a grounding plate 24 is connected to the guard plate 6. FIG. 7(I) is a 
schematic perspective view of such an arrangement, and FIG. 7(II) is a 
cross sectional view of the arrangement. A latent electrostatic coupling 
space is formed below the generator plate and the detector plate. 
FIGS. 8 to 12 each explain an apparatus for use in the third method of 
reading information. 
In FIG. 8, numeral 6 indicates a guard plate to prevent formation of an 
electrostatic coupling space other than a space formed by end surfaces 19 
and 18 of a generator plate 2 and a detector plate 3. The plates 2 and 3 
are disposed such that they are electrically not in contact with each 
other. In FIG. 8, each of the two plates is provided with a guard plate. 
However, two guard plates are not always required. 
The end surfaces 19 and 18 of the above two plates are not necessarily 
required to be at the same level. However, when the distance from an 
electrically conductive film to be detected is smaller and when an 
effective area formed by the end surfaces and the electrically conductive 
film is larger, a higher detection sensitivity can be achieved. The end 
surfaces 19 and 18 are disposed such that a latent electrostatic coupling 
space between the two plates is limited to a space below the end surfaces 
19 and 18 of the plates and that the end surfaces 19 and 18 are not 
substantially electrostatically coupled with each other. 
When widths of a bar code are read, a card is moved at right angles with 
bars. When the electrically conductive film has a form indicating 
two-dimensional information, the information can be identified by moving a 
card in X and Y directions. A reading (decoding) portion may be moved 
relative to the card in order to read the information. 
FIG. 9 is a schematic cross sectional of an apparatus shown in FIG. 8 to 
explain the function thereof. FIG. 9(I) shows an embodiment where an 
electrically conductive film 21 is not positioned below end portions of 
the two plates 2 and 3. Numerals 22 and 23 each indicate an electrically 
nonconductive film covering the electrically conductive film 21. In this 
state, the generator plate 2 and the detector plate 3 are not 
substantially electrostatically coupled. However, a latent electrostatic 
coupling space is formed below the generator plate 2 and the detector 
plate 3. FIG. 9(II) shows an embodiment where the electrically conductive 
film 21 is positioned below the above two plates 2 and 3, i.e. within the 
latent electrostatic coupling space. In this state, the generator plate 2 
and the electrically conductive film 21 are electrostatically coupled, and 
the electrically conductive film 21 and the detector plate 3 are 
electrostatically coupled. As a result, a pulse provided to the generator 
plate 2 is detected by the detector plate 3 through the electrically 
conductive film 21. Therefore, a size of the electrically conductive film 
is determined on the basis of a product of a detection time and speed, and 
a distance where no detection is effected is also determined as a piece of 
information. 
FIG. 10 shows an embodiment where a generator plate 2 and a detector plate 
3 are concentrically arranged, one guard plate 6 is arranged between the 
generator plate 2 and the detector plate 3 and the other guard plate 
outside the detector plate 3 arranged outside. Due to such an arrangement 
of the guard plates, the latent electrostatic coupling space is limited to 
the information member direction. This arrangement of a reading portion 
makes it possible to decrease directional dependency of detection 
sensitivity. 
FIG. 11 shows an embodiment where a generator plate 2 is arranged on one 
side of an information member 1 and a detector plate 3 is arranged on the 
other side of the information member 1. A guard plate 6 having a conical 
form and having a hole in its lower portion, which works to limit a latent 
electrostatic coupling space, is arranged around the generator plate 2. 
The guard plate 6 may have a flat form with a hole. The detector plate 3 
is preferably arranged a certain distance apart from a position located in 
the information member thickness direction directly below the generator 
plate 2. In this arrangement, good detection sensitivity can be always 
obtained even if the position of an electrically conductive film varies 
within a card in the thickness direction of the card. 
FIG. 12 shows the principle for generation of electrostatic coupling. FIG. 
12(I) shows a case where a condenser necessary for the electrostatic 
coupling is not formed. FIG. 12(II) shows a case where an electrically 
conductive film 21 forms a condenser together with a generator plate 2 and 
a detector plate 3. 
FIGS. 13 and 14 show results of measurement, with an oscilloscope, of an 
electrostatic shielding effect of the electrostatic coupling space in the 
apparatus shown in FIG. 2 according to the first method of reading 
information. FIG. 13(I) shows a pulse applied to the generator plate. FIG. 
13(II) shows a waveform obtained after a signal detected with the detector 
plate without any electrically conductive film in the electrostatic 
coupling space is transmitted into a potential detecting circuit. FIG. 14 
shows a waveform of a signal obtained from the potential detecting circuit 
when the electrically conductive film is present in the electrostatic 
coupling space shown in FIG. 12. FIG. 14(I) shows a signal applied to the 
generator plate, and FIG. 14(II) shows a waveform obtained from the 
detector plate. In FIG. 13, clear electrostatic coupling is observed, and 
in FIG. 14, there is observed an electrostatic shielding effect obtained 
due to the presence of an electrically conductive film in the 
electrostatic coupling space. 
FIGS. 15 and 16 are graphs showing results of measurement, with an 
oscilloscope, of an electrostatic shielding effect in the latent 
electrostatic coupling space in the apparatus shown in FIG. 3 according to 
the second method of identifying information. FIG. 15(I) shows a pulse 
applied to the generator plate, and FIG. 15(II) shows a waveform obtained 
after a signal detected with the detector plate 3 without any electrically 
conductive film in the latent electrostatic coupling space is transmitted 
into the potential detecting circuit 9. 
FIG. 16 shows a waveform obtained from the detector plate when the 
electrically conductive film having a grounded potential is positioned in 
the latent electrostatic coupling space in FIG. 15. FIG. 16(I) shows a 
signal applied to the generator plate, and FIG. 16(II) shows a waveform 
obtained from the detector plate. In FIG. 15, clear electrostatic coupling 
is observed, and in FIG. 16, there is observed an electrostatic shielding 
effect produced due to the presence of the electrically conductive film in 
the latent electrostatic coupling space. 
FIGS. 17 and 18 are graph showing results of measurement, with an 
oscilloscope, of an electrostatic induction effect in the latent 
electrostatic coupling space in the apparatus shown in FIG. 8 according to 
the third method of identifying information. FIG. 17(I) shows a pulse 
applied to the generator plate, and FIG. 17(II) shows a waveform detected 
after a signal detected with the detector plate 3 without any electrically 
conductive film in the latent electrostatic coupling space is transmitted 
into the potential detecting circuit 9. FIG. 18 shows a waveform of a 
signal obtained from the detector signal when the electrically conductive 
film is present in the latent electrostatic coupling space. FIG. 18(I) 
shows a signal applied to the generator plate, and FIG. 18(II) shows a 
waveform of a signal obtained from the detector plate. In FIG. 17, absence 
of electrostatic coupling is clearly observed, and in FIG. 18, there is 
observed an electrostatic induction effect produced due to the presence of 
the electrically conductive film in the latent electrostatic coupling 
space. 
FIG. 19 shows one embodiment of the electrically conductive film having a 
form expressing information, suitable for use in the first and second 
methods of identifying information. An electrically conductive film 21 in 
FIG. 19 has a pattern of a bar code. It is preferable to stabilize a 
grounded potential of the electrically conductive film by electrically 
connecting its bars with an electrically conductive connection member 25, 
and connecting an electrostatically coupling member 26, which 
electrostatically couples with the grounding plate, to one end of the 
connection member 25 thereby to form an electrostatic coupling space 
between the coupling member and the grounding plate. However, addition of 
the above connection member and the coupling member is not necessarily 
required when each of the bars is electrically isolated and when those 
portions of the bars which are positioned outside the electrostatic 
coupling space or the latent electrostatic coupling space overlap the 
grounding plate areawise fully and form sufficient electrostatic coupling 
with the grounding plate. 
FIG. 20 shows one embodiment of the information member 1 which is a bar 
code having a positive pattern, and FIG. 21 shows one embodiment of the 
information member 1 which is a bar code having a negative pattern. The 
information provided to the pattern of this bar code comprises a bar width 
and an interbar distance. The width and the distance can be determined by 
multiplying a moving rate of the information member and the reciprocal of 
a frequency of a pulse to be detected and multiplying the resultant 
product and a count number of the pulse counted or not counted. 
FIG. 22 shows information comprising letters, in which the information is 
identified as X-Y axial two-dimensional information. In this case, the 
information may be identified as two-dimensional one by identifying a 
unidirectional information in the X- or Y-axis direction and scanning it 
in the Y- or X-axis direction. 
The information carrying member formed by covering an electrically 
conductive film having a form expressing information with an electrically 
nonconductive film will be explained hereinafter. 
The electrically nonconductive material includes plastic, paper, and the 
like, which have been heretofore used for a card, securities, etc. 
The electrically conductive film may be substantially concealed by 
coloring, naming, numbering and/or patterning the electrically 
nonconductive film with at least one means of a laminator, a printing 
machine, a thermal transfer printer, a sublimation transfer printer, a 
wire dot printer and an ink-jet printer. 
Examples of the electrically conductive material are metals such as Ni, Fe, 
Pd, Cr, Ti, Cu, Ag, Au, Al, Zn, Co, etc., and alloys of these; oxides such 
as SnO.sub.2, In.sub.2 O.sub.3, CdO, ZnO, Cd.sub.2 SO.sub.4, etc., and 
products prepared by doping these with Sb, F, Sn, W, Mo, or Al; monoxides 
such as Cu.sub.2 S, CdS, ZnS, LaB.sub.6, TiN, TiC, ZrN, ZrB.sub.2, HfN, 
etc.; an electrically conductive carbon, graphite, and the like. 
In order to conceal the electrically conductive film to a greater extent by 
providing a design, a pattern, a symbol or the like thereon, it is 
preferable to use an electrically conductive film having high clearness 
and a low density. When it has a high density, it may be rendered 
invisible by providing a white concealing layer. 
When the electrically conductive film is produced so as to have a form 
expressing information, i.e. formed into a variety of patterns, 
conventionally known methods can be employed therefor. For example, the 
electrically conductive film can be formed by an evaporation method, a 
chemical plating method, an electroplating method, a method of applying or 
printing an electrically conductive coating composition, a method of 
attaching a metal foil, applying a photosensitive material, baking a 
pattern and then dissolving an unnecessary portion to remove it, a method 
of attaching a metal foil and then etching or applying a laser to the 
metal foil to form a pattern, or the like. Further, as a simpler method, a 
pattern may be formed by using a thermal transfer ribbon using an 
electrically conductive thermal ink by means of a thermal head, and the 
like. 
The electrically conductive pattern after formed may be covered or 
concealed with an electrically nonconductive material by various known 
methods, e.g., by attaching an electrically nonconductive material having 
an adhesive applied to one of its surfaces, by applying a thermoplastic 
resin to the electrically conductive pattern and subjecting it to a heat 
roll, by applying an electrically nonconductive ink by means of a printing 
machine, or by some other method. Further, the electrically nonconductive 
film may be formed by using a thermal transfer ribbon using an 
electrically conductive thermal ink. 
According to the method of reading information, provided by this invention, 
it is possible to use an information carrying member formed, in a sandwich 
structure, of an electrically conductive member in which various pieces of 
information are stored and an electrically nonconductive material covering 
or concealing the electrically conductive member. Therefore, the 
information can be easily rendered invisible. And, the information 
carrying member of this invention is only required to have an electrically 
conductive member having a pattern and an electrically nonconductive 
material. Therefore, the information carrying member has high resistance 
to environmental change, and the method of this invention has an advantage 
that the pattern therefor can be formed by a variety of methods such as a 
thermal transfer method, and the like. 
According to the method of identifying reading information, provided by 
this invention, individual information can be recorded and identified at a 
real time. And, the method of this invention has an advantage that it can 
be also employed as means of providing constant information when a pattern 
is formed by a printing method, etc. 
According to the method of identifying reading information, provided by 
this invention, since the information reading portion is structurally only 
required to have the generator plate, the detector plate and, optionally, 
the guard plate, these plates can be easily arranged unidimensionally or 
two-dimensionally. Further, the method of this invention therefore has an 
advantage that two-dimensional information can be easily identified by 
moving the electrically conductive member unidimensionally or by fixing 
it. 
According to the method of identifying information, provided by this 
invention, the method of this invention can be applied to a 
unidimensional, two-dimensional or fixed information identifying method by 
combining it with other identifying method. And, the method of this 
invention has an advantage that it can be automatized easily. 
According to the method of identifying information, provided by this 
invention, means of providing the electrically conductive member with 
information is simple and less expensive. For example, the method of this 
invention has an advantage that a conventional bar code printer can be 
used as it is when an electrically conductive thermal transfer sheet is 
used. 
EXAMPLES 
The method of identifying information, provided by this invention, is 
explained below by reference to Examples in which information members 
having an electrically conductive film expressing information are prepared 
by mainly using a thermal transfer ribbon. In Examples, "part" stands for 
"part by weight". 
Ink Composition A 
A coating liquid having the following composition was dispersed with an 
attriter at room temperature to give an ink for a peel layer. 
______________________________________ 
White pigment (titanium oxide) 
20 parts 
Carnauba wax 1 part 
Polyvinyl butyral ("#3300-1" supplied 
3 parts 
by Denki Kagaku Kogyo K.K.) 
Isopropyl alcohol 76 parts 
______________________________________ 
Ink Composition B 
A coating liquid having the following composition was dissolved by means of 
a DISPER at room temperature to give an ink for a levelling layer. 
______________________________________ 
Styrene acrylic resin ("MH7025" 
10 parts 
supplied by Fujikura Kasei K.K.) 
Toluene 70 parts 
Methyl isobutyl ketone 
20 parts 
______________________________________ 
Ink Composition C 
A coating liquid having the following composition was dispersed with an 
attriter at room temperature to give an ink for an electrically conductive 
ink layer. 
______________________________________ 
Electrically conductive carbon ("Seast SO" 
20 parts 
supplied by Tokai Carbon K.K.) 
Petroleum resin ("ARKON M70" 
20 parts 
supplied by Arakawa Kagaku K.K.) 
Toluene 60 parts 
______________________________________ 
Ink Composition D 
A coating liquid having the following composition was dispersed with an 
attriter at room temperature to give an ink for an overcoat layer. 
______________________________________ 
Polyamide resin ("DPX-640" supplied 
20 parts 
by Henkel) 
Carnauba wax 1 part 
Toluene 69 parts 
Isopropyl alcohol 10 parts 
______________________________________ 
Ink Composition E 
A coating liquid having the following composition was dispersed with an 
attriter at room temperature to give an ink for a concealing layer. 
______________________________________ 
Polyamide resin ("DPX-640" supplied 
10 parts 
by Henkel) 
Carnauba wax 1 part 
Titanium oxide 60 parts 
Toluene 20 parts 
Isopropyl alcohol 9 parts 
______________________________________ 
The following thermal transfer ribbons were prepared from the above ink 
compositions A to E. These ink compositions were all applied by a gravure 
coating method in an amount specified below. Polyethylene terephthalate 
films having a thickness of 6 .mu.m were used as a substrate. 
Thermal Transfer Ribbon 1 
0.3 g/m.sup.2 of the ink A was applied to a substrate, and 1.0 g/m.sup.2 of 
the ink B was applied thereon. Aluminum was evaporated thereon to form an 
electrically conductive film having a thickness of 100 .ANG., and then, 
1.2 g/m.sup.2 of the ink D was applied to give a thermal transfer ribbon. 
Thermal Transfer Ribbon 2 
1.0 g/m.sup.2 of the ink B was applied to a substrate, and aluminum was 
evaporated thereon to form an electrically conductive film having a 
thickness of 100 .ANG.. Then, 1.2 g/m.sup.2 of the ink D was applied 
thereon to give a thermal transfer ribbon. 
Thermal Transfer Ribbon 3 
0.3 g/m.sup.2 of the ink A was applied to a substrate, and then, 0.5 
g/m.sup.2 of the ink C was applied thereon to give a thermal transfer 
ribbon. 
Thermal Transfer Ribbon 4 
0.4 g/m.sup.2 of the ink C was applied to a substrate, and then, 0.5 
g/m.sup.2 of the ink D was applied thereon to give a thermal transfer 
ribbon. 
Thermal Transfer Ribbon 5 
3.0 g/m.sup.2 of the ink E was applied to a substrate to give a thermal 
transfer ribbon. 
Information members were prepared by using the above thermal transfer 
ribbons. 
Information patterns A to D indicated in Table 1 are as follows. 
Pattern A: The pattern was formed as shown in FIG. 19. The pattern, 
however, was without a member for formation of an electrostatic coupling 
space. 
Pattern B: The pattern was a positive pattern formed as shown in FIG. 20. 
Pattern C: The pattern was a negative pattern formed as shown in FIG. 21. 
Pattern D: The pattern was formed as shown in FIG. 22. 
Method of Forming Patterns: 
a. Bar code patterns were printed with a bar code printer (B-30-S-1, 
supplied by Tokyo Denki K.K.). 
b. Connection members and the negative pattern were printed with a printer 
("CopiLman FN-P300" using a thermal transfer method, supplied by 
Matsushita Electric Industrial Co., Ltd.). 
The detection sensitivity was measured by using an apparatus shown in FIG. 
2. 
Table 1 shows Examples 1 to 8. 
TABLE 1 
______________________________________ 
Examples 
1 2 3 4 5 6 7 8 
______________________________________ 
Thermal transfer 
ribbon 
1 .smallcircle. 
-- -- -- .smallcircle. 
-- .smallcircle. 
.smallcircle. 
2 -- .smallcircle. 
-- -- -- .smallcircle. 
-- -- 
3 -- -- .smallcircle. 
-- -- -- -- -- 
4 -- -- -- .smallcircle. 
-- -- -- -- 
5 -- -- -- -- .smallcircle. 
.smallcircle. 
.smallcircle. 
.smallcircle. 
Pattern A A A A B C C D 
Detection sensitity 
.largecircle. 
.largecircle. 
.largecircle. 
.largecircle. 
.largecircle. 
.circleincircle. 
.circleincircle. 
.largecircle. 
______________________________________ 
The detection sensitivity was rated as follows. 
.largecircle.: Readable stably. 
.circleincircle.: Readable very stably. 
In Example 1, a peel layer containing the white pigment was present on an 
evaporated layer after the transfer, whereby a white bar code pattern was 
obtained. 
In Example 2, a bar code pattern having metallic gloss was obtained. 
In Example 3, a peel layer containing the white pigment was present on a 
layer containing the electrically conductive carbon after the transfer, 
whereby a grayish white bar code pattern was obtained. 
In Example 4, a black bar code pattern was obtained. 
In Examples 5 to 8, a white concealing layer formed from the thermal 
transfer ribbon 5 was positioned on an electrically conductive pattern 
formed from the thermal transfer ribbon 1 or 2, and the electrically 
conductive pattern was rendered invisible. In addition, in Example 7, 
characters were printed by further using a usual thermal transfer ribbon, 
and in Example 8, a design was formed further by offset printing.