U.S. patent application number 09/747410 was filed with the patent office on 2002-06-20 for recognition system for identification-card singularity.
Invention is credited to Toda, Kohji.
Application Number | 20020074414 09/747410 |
Document ID | / |
Family ID | 25004939 |
Filed Date | 2002-06-20 |
United States Patent
Application |
20020074414 |
Kind Code |
A1 |
Toda, Kohji |
June 20, 2002 |
RECOGNITION SYSTEM FOR IDENTIFICATION-CARD SINGULARITY
Abstract
A recognition system for identification-card singularity
comprises an identification card, a detail communication device
attached to a detail computer, and a master communication device
attached to a master computer. The identification card consists of
a first piezoelectric substrate, an individual coded IDT, and a
first electrode-group. The detail communication device consists of
a second piezoelectric substrate and transmitting- and receiving
sections. The transmitting section is composed of a first
bipolar-pulse generator, first and second coded IDTs, a second
electrode-group, an envelope detecting device, and a
monopolar-pulse generator. The receiving section is composed of a
third electrode-group, a second bipolar-pulse generator, an
intermediary IDT, third and fourth coded IDTs, and a detecting
device. If the identification card is set in the detail
communication device, a pulse is generated at the first
bipolar-pulse generator at regular intervals. When the pulse is
applied to the individual coded IDT, an individual SAW is excited
on the first piezoelectric substrate. The individual SAW is
detected at the first electrode group as an individual double-coded
burst-signal, which is converted into an individual double-coded
digital-signal at the monopolar-pulse generator and delivered into
a digital network. When the individual double-coded digital-signal
is received by the master communication device, the signal decoding
is achieved, so that the identification-card singularity is
recognized by the master communication device.
Inventors: |
Toda, Kohji; (Yokosuka,
JP) |
Correspondence
Address: |
Kohji Toda
1-49-18 Futaba
Yokosuka
239-0814
JP
|
Family ID: |
25004939 |
Appl. No.: |
09/747410 |
Filed: |
December 19, 2000 |
Current U.S.
Class: |
235/492 |
Current CPC
Class: |
G06K 19/0675 20130101;
G06Q 20/341 20130101; G06K 19/0723 20130101; G06K 19/067 20130101;
G06Q 20/4097 20130101; G07F 7/1008 20130101; G06K 7/10009
20130101 |
Class at
Publication: |
235/492 |
International
Class: |
G06K 019/06 |
Claims
What is claimed is:
1. A recognition system for identification-card singularity
comprising: an identification card consisting of a first
piezoelectric substrate, an individual coded IDT consisting of
interdigital electrode pairs Pi (i=1, 2, . . . , n), of which two
neighbors are at a distance L from each other, and having an
individual coded pattern, a first electrode-group consisting of an
interdigital electrode I.sub.0 and an interdigital electrode
I.sub.i (i=1) at a distance iL (i=1) from said interdigital
electrode I.sub.0; a detail communication device attached to a
detail computer and consisting of a second piezoelectric substrate
and transmitting- and receiving sections, said transmitting section
being composed of a first bipolar-pulse generator, a first coded
IDT consisting of interdigital electrode pairs Pi (i=1, 2, . . . ,
n), of which two neighbors are at said distance L from each other,
and having a first coded pattern, a second coded IDT with the same
construction as said first coded IDT except for having a second
coded pattern, a second electrode-group consisting of an
interdigital electrode A.sub.0 and an interdigital electrode
A.sub.i (i=1) at said distance iL (i=1) from said interdigital
electrode A.sub.0, an envelope detecting device connected with said
second electrode-group, a monopolar-pulse generator; and a master
communication device attached to a master computer and having the
same construction as said detail communication device, and
consisting of a third piezoelectric substrate and transmitting- and
receiving sections, said receiving section being composed of a
third electrode-group consisting of a central interdigital
electrode B.sub.0M, a left interdigital electrode B.sub.-1M at a
distance L.sub.0 from said central interdigital electrode B.sub.0M,
and a right interdigital electrode B.sub.iM (i=1) at a distance
L.sub.0+iL (i=1) from said central interdigital electrode B.sub.0M,
a second bipolar-pulse generator, an intermediary IDT, a third
coded IDT with the same construction as said first coded IDT except
for having a third coded pattern, a fourth coded IDT with the same
construction as said first coded IDT except for having a fourth
coded pattern, and a detecting device, said first bipolar-pulse
generator generating a pulse while said identification card is set
in said detail communication device, said individual coded IDT
exciting an individual SAW on said first piezoelectric substrate
when receiving said pulse, said interdigital electrode I.sub.0
detecting an individual coded burst-signal corresponding to said
individual coded pattern, said interdigital electrode I.sub.i
detecting said individual coded burst-signal after a time
corresponding to said distance iL, said envelope detecting device
receiving an individual double-coded burst-signal made from said
individual coded burst-signals at said interdigital electrodes
I.sub.0 and I.sub.i, said monopolar-pulse generator causing an
individual double-coded digital-signal via said envelope detecting
device, and delivering said individual double-coded digital-signal
into a digital network, said left interdigital electrode B.sub.-1M
and said right interdigital electrode B.sub.iM exciting first- and
second SAWs, respectively, on said third piezoelectric substrate
when receiving said individual double-coded digital-signal from
said digital network, said second bipolar-pulse generator causing
an individual mono-coded digital-signal from said first- and second
SAWs via said central interdigital electrode B.sub.0M, said
intermediary IDT exciting a third SAW composed of an individual
coded row of burst-wave groups on said third piezoelectric
substrate when receiving said individual mono-coded digital-signal,
said third- and fourth coded IDTs detecting first- and second
decoded pulses, respectively, when each of said burst-wave groups
correlates to said third- and fourth coded patterns, respectively,
said detecting device detecting an output digital-signal, which is
based on said first- and second decoded pulses and is equivalent to
said individual coded pattern, and recognizing the
identification-card singularity from said output
digital-signal.
2. A recognition system for identification-card singularity as
defined in claim 1, wherein said transmitting section of said
master communication device delivers a coded request digital-signal
asking for password into said digital network just after
recognition of said identification-card singularity, said receiving
section of said detail communication device receives said coded
request digital-signal asking for password from said digital
network, said first bipolar-pulse generator generates bipolar
pulses (-1 and 1) that form a password digital-signal, except when
generating said pulse for said identification card at regular
intervals, said first- and second coded IDTs excite fourth- and
fifth SAWs on said second piezoelectric substrate when receiving
said bipolar pulses (-1 and 1), respectively, said interdigital
electrode A.sub.0 detects a coded burst-signal corresponding to
said first- and second coded patterns, respectively, said
interdigital electrode A.sub.i detects said coded burst-signal
after a time corresponding to said distance iL, said envelope
detecting device receives a double-coded burst-signal made from
said coded burst-signals at said interdigital electrodes A.sub.0
and A.sub.i, said monopolar-pulse generator causes a double-coded
digital-signal via said envelope detecting device, and delivers
said double-coded digital-signal into said digital network, said
left interdigital electrode B.sub.-1M and said right interdigital
electrode B.sub.iM receive said double-coded digital-signal
simultaneously from said digital network, said detecting device
detects an output digital-signal equivalent to said password
digital-signal.
3. A recognition system for identification-card singularity as
defined in claim 1, wherein said first-, second-, third-, and
fourth coded IDTs consist of at least three interdigital electrode
pairs, respectively.
4. A recognition system for identification-card singularity as
defined in claim 1, wherein said third- and fourth coded patterns
are in reverse to said first- and second coded patterns,
respectively.
5. A recognition system for identification-card singularity as
defined in claim 1, wherein said individual coded IDT is
constructed of multiple times four coded IDTs classified into at
most two types that correspond to said first- and second coded
IDTs, respectively.
6. A recognition system for identification-card singularity as
defined in claim 1 further comprising a bipolar-pulse generator in
place of said monopolar-pulse generator.
7. A recognition system for identification-card singularity as
defined in claim 1, wherein said individual coded IDT comprises at
least two parts that are electrically separated and in uneven
parallel with each other, said at least two parts excite at least
two individual SAWs, respectively, on said first piezoelectric
substrate when receiving said pulse from said first bipolar-pulse
generator simultaneously, said interdigital electrode I.sub.0
detects at least two individual coded burst-signals one by one when
receiving said at least two individual SAWs, said interdigital
electrode I.sub.1 also detects said at least two individual coded
burst-signals one by one when receiving said at least two
individual SAWs, said at least two individual coded burst-signals
at said interdigital electrodes I.sub.0 and I.sub.1 forming a mixed
double-coded burst-signal corresponding to said individual
double-coded burst-signal received at said envelope detecting
device.
8. A recognition system for identification-card singularity as
defined in claim 1, wherein said identification card further
comprises a fourth electrode-group consisting of an interdigital
electrode J.sub.0 and an interdigital electrode J.sub.1 (i=1) at a
distance iL (i=1) from said interdigital electrode J.sub.0, said
individual coded IDT comprises first- and second parts that are
electrically separated and vertical from each other, said first-
and second parts excite first- and second individual SAWs,
respectively, on said first piezoelectric substrate when receiving
said pulse from said first bipolar-pulse generator simultaneously,
said interdigital electrode J.sub.0 detects a first individual
coded burst-signal corresponding to said first individual SAW, said
interdigital electrode J.sub.1 detects said first individual coded
burst-signal again, said interdigital electrode I.sub.0 detects a
second individual coded burst-signal corresponding to said second
individual SAW just after said interdigital electrode J.sub.0
detects said first individual coded burst-signal, said interdigital
electrode I.sub.i detects said second individual coded burst-signal
just after said interdigital electrode J.sub.1 detects said first
individual coded burst-signal, said first- and second individual
coded burst-signals at said interdigital electrodes J.sub.0,
J.sub.i, I.sub.0 and I.sub.i forming a mixed double-coded
burst-signal corresponding to said individual double-coded
burst-signal received at said envelope detecting device.
9. A recognition system for identification-card singularity as
defined in claim 1, wherein said first electrode-group includes at
least two interdigital electrodes I.sub.i {i=1, 2, . . . , (n-1)}
at a distance iL {i=1, 2, . . . , (n-1)}, respectively, from said
interdigital electrode I.sub.0, said second electrode-group
includes at least two interdigital electrodes A.sub.i {i=1, 2, . .
. , (n-1)} at a distance iL {i=1, 2, . . . , (n-1)}, respectively,
from said interdigital electrode A.sub.0, said third
electrode-group includes at least two right interdigital electrodes
B.sub.iM {i=1, 2, . . . , (n-1)} at a distance L.sub.0+iL {i=1, 2,
. . . , (n-1)}, respectively, from said central interdigital
electrode B.sub.0M, said identification card further comprises a
first switch that connects said envelope detecting device with said
at least two interdigital electrodes I.sub.i in turn, said
transmitting section further comprises a second switch that
connects said envelope detecting device with said at least two
interdigital electrodes A.sub.i in turn, said receiving section
further comprises a third switch that connects said digital network
with said at least two right interdigital electrode B.sub.iM in
turn.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a recognition system for
identification-card singularity on digital network communication
between a master station and detail stations by means of using a
master communication device attached to the master station, detail
communication devices attached to the detail stations,
respectively, and identification cards set in the detail
communication devices, respectively.
[0003] 2. Description of the Prior Art
[0004] It is most important on digital network communication to
prevent the influence of noises and invaders. However, it is
difficult to keep the communication secret by the coding technique
based on conventional hard-wears such as magnetic cards and IC
cards. The magnetic cards are very convenient and popular, however
it is easy to make copies thereof or steal passwords. Therefore
damages by unlawful using of credit cards, cash cards, prepaid
cards, and so on are increasing year after year. The IC cards are
superior to the magnetic cards in difficulty in counterfeiting of
cards, however it is not enough to keep the communication secret
thoroughly. Thus, conventional hard-wears have problems on keeping
a communication security.
SUMMARY OF THE INVENTION
[0005] An object of the present invention is to provide an
identification card useful as credit card, cash card, key, and
others.
[0006] Another object of the present invention is to provide an
identification card excellent in difficulty in counterfeiting and
stealing of passwords.
[0007] Another object of the present invention is to provide a
recognition system for identification-card singularity capable of
recognizing the identification-card singularity in secret.
[0008] Another object of the present invention is to provide a
recognition system for identification-card singularity capable of
low electric power consumption.
[0009] Another object of the present invention is to provide a
recognition system for identification-card singularity excellent in
durability and manufacturing.
[0010] A still other object of the present invention is to provide
a recognition system for identification-card singularity having a
small size and a simple structure.
[0011] According to one aspect of the present invention there is
provided a recognition system for identification-card singularity
comprising a master communication device attached to a master
computer, a detail communication device attached to a detail
computer, and an identification card set in the detail
communication device. The identification card consists a first
piezoelectric substrate, an individual coded interdigital
transducer (IDT), and a first electrode-group. The individual coded
IDT consists of interdigital electrode pairs Pi (i=1, 2, . . . ,
n), of which two neighbors are at a distance L from each other, and
has an individual coded pattern. The first electrode-group consists
of an interdigital electrode I.sub.0 and an interdigital electrode
I.sub.i (i=1) at a distance iL (i=1) from the interdigital
electrode I.sub.0. The detail communication device consists of a
second piezoelectric substrate and transmitting- and receiving
sections. The transmitting section is composed of a first
bipolar-pulse generator, first and second coded IDTs, a second
electrode-group, an envelope detecting device, and a
monopolar-pulse generator. The first coded IDT consists of
interdigital electrode pairs Pi (i=1, 2, . . . , n), of which two
neighbors are at the distance L from each other, and has a first
coded pattern. The second coded IDT has the same construction as
the first coded IDT except for having a second coded pattern. The
second electrode-group consists of an interdigital electrode
A.sub.0 and an interdigital electrode A.sub.i (i=1) at the distance
iL (i=1) from the interdigital electrode A.sub.0. The envelope
detecting device is connected with the second electrode-group. The
master communication device has the same construction as the detail
communication device, and consists of a third piezoelectric
substrate and transmitting- and receiving sections. The receiving
section is composed of a third electrode-group, a second
bipolar-pulse generator, an intermediary IDT, third and fourth
coded IDTs, and a detecting device. The third electrode-group
consists of a central interdigital electrode B.sub.0M, a left
interdigital electrode B.sub.-1M at a distance L.sub.0 from the
central interdigital electrode B.sub.0M, and a right interdigital
electrode B.sub.iM (i=1) at a distance L.sub.0+iL (i=1) from the
central interdigital electrode B.sub.0M. The third coded IDT has
the same construction as the first coded IDT except for having a
third coded pattern. The fourth coded IDT has the same construction
as the first coded IDT except for having a fourth coded
pattern.
[0012] If the identification card is set in the detail
communication device, a pulse generated at the first bipolar-pulse
generator is applied to the individual coded IDT, so that an
individual SAW corresponding to the individual coded pattern is
excited on the first piezoelectric substrate. The individual SAW is
detected as an individual coded burst-signal at the interdigital
electrode I.sub.0, and after a time corresponding to the distance
L, at the interdigital electrode I.sub.1 again. The individual
coded burst-signals at the interdigital electrodes I.sub.0 and
I.sub.1 form an individual double-coded burst-signal, which arrives
at the monopolar-pulse generator via the envelope detecting device.
Thus, an individual double-coded digital-signal is obtained at the
monopolar-pulse generator, and is delivered into a digital network.
On the other hand, when the individual double-coded digital-signal
arrives at the master communication device, it is received at the
left interdigital electrode B.sub.-1M and the right interdigital
electrode B.sub.1M, respectively. In this time, first- and second
SAWs are excited on the third piezoelectric substrate. The first
SAW arrives at the central interdigital electrode B.sub.0M by a
time corresponding to the distance L before the second SAW arrives
at the central interdigital electrode B.sub.0M. As a result, the
individual double-coded digital-signal is converted into an
individual mono-coded burst-signal at the central interdigital
electrode B.sub.0M. The individual mono-coded burst-signal is
converted into an individual mono-coded digital-signal at the
second bipolar-pulse generator. The individual mono-coded
digital-signal is applied to the intermediary IDT. And then, a
third SAW composed of an individual coded row of burst-wave groups
is excited on the third piezoelectric substrate. When the
burst-wave group correlates to the third- and fourth coded
patterns, respectively, first- and second decoded pulses are
detected at the third- and fourth coded IDTs, respectively. As a
result, an output digital-signal equivalent to the individual coded
pattern, is detected at the detecting device. Therefore, the
identification-card singularity is recognized from the output
digital-signal.
[0013] In addition, for further securing such a communication
system, a double-coded request digital-signal asking for password
is delivered from the transmitting section of the master
communication device into the digital network toward the detail
communication device just after recognition of the
identification-card singularity. The double-coded request
digital-signal asking for password is received at the receiving
section of the detail communication device through the digital
network. And then, a double-coded password digital-signal is
delivered from the transmitting section of the detail communication
device into the digital network. The double-coded password
digital-signal is received at the receiving section of the master
communication device through the digital network. Thus, the
communication between the master communication device and the
detail communication device starts.
[0014] According to another aspect of the present invention there
are provided first-, second-, third-, and fourth coded IDTs
consisting of at least three interdigital electrode pairs,
respectively.
[0015] According to another aspect of the present invention there
are provided third- and fourth coded IDTs having third- and fourth
coded patterns in reverse to the first- and second coded patterns,
respectively.
[0016] According to another aspect of the present invention there
is provided an individual coded IDT constructed of multiple times
four coded IDTs classified into at most two types that correspond
to the first- and second coded IDTs, respectively.
[0017] According to another aspect of the present invention there
is provided a bipolar-pulse generator in place of the
monopolar-pulse generator.
[0018] According to another aspect of the present invention there
is provided an individual coded IDT comprising at least two parts
that are electrically separated and in uneven parallel with each
other. The parts excite individual SAWs, respectively, on the first
piezoelectric substrate when receiving the pulse from the first
bipolar-pulse generator simultaneously. The interdigital electrode
I.sub.0 detects individual coded burst-signals one by one when
receiving the individual SAWs. The interdigital electrode I.sub.1
also detects the individual coded burst-signals one by one when
receiving the individual SAWs. As a result, the individual coded
burst-signals at the interdigital electrodes I.sub.0 and I.sub.1
form a mixed double-coded burst-signal corresponding to the
individual double-coded burst-signal received at the envelope
detecting device.
[0019] According to other aspect of the present invention there are
provided an individual coded IDT comprising first- and second parts
that are electrically separated and vertical from each other, and
an identification card further comprising a fourth electrode-group
that consists of an interdigital electrode J.sub.0 and an
interdigital electrode J.sub.i (i=1) at a distance iL (i=1) from
the interdigital electrode J.sub.0. The first- and second parts
excite first- and second individual SAWs, respectively, on the
first piezoelectric substrate when receiving the pulse from the
first bipolar-pulse generator simultaneously. The interdigital
electrode J.sub.0 detects a first individual coded burst-signal
corresponding to the first individual SAW. The interdigital
electrode J.sub.1 detects the first individual coded burst-signal
again. The interdigital electrode I.sub.0 detects a second
individual coded burst-signal corresponding to the second
individual SAW just after the interdigital electrode J.sub.0
detects the first individual coded burst-signal. The interdigital
electrode I.sub.1 detects the second individual coded burst-signal
just after the interdigital electrode J.sub.1 detects the first
individual coded burst-signal. As a result, the first- and second
individual coded burst-signals at the interdigital electrodes
J.sub.0, J.sub.1, I.sub.0 and I.sub.1 form a mixed double-coded
burst-signal corresponding to the individual double-coded
burst-signal received at the envelope detecting device.
[0020] According to a further aspect of the present invention there
are provided a first electrode-group, a second electrode-group, a
third electrode-group, an identification card, a transmitting
section, and a receiving section. The first electrode-group
includes at least two interdigital electrodes I.sub.1 {i=1, 2, . .
. , (n-1)} at a distance iL {i=1, 2, . . . , (n-1)}, respectively,
from the interdigital electrode I.sub.0. The second electrode-group
includes at least two interdigital electrodes A.sub.i {i=1, 2, . .
. , (n-1)} at a distance iL {i=1, 2, . . . , (n-1)}, respectively,
from the interdigital electrode A.sub.0. The third electrode-group
includes at least two right interdigital electrodes B.sub.iM {i=1,
2, . . . , (n-1)} at a distance L.sub.0+iL {i=1, 2, . . . , (n-1)},
respectively, from the central interdigital electrode B.sub.0M. The
identification card further comprises a first switch that connects
the envelope detecting device with the interdigital electrodes
I.sub.i in turn. The transmitting section further comprises a
second switch that connects the envelope detecting device with the
interdigital electrodes A.sub.1 in turn. The receiving section
further comprises a third switch that connects the digital network
with the right interdigital electrode B.sub.iM in turn.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Other features and advantages of the invention will be
clarified from the following description with reference to the
attached drawings.
[0022] FIG. 1 shows a schematic illustration of a detail
communication device with an identification card, in a recognition
system for identification-card singularity, according to a first
embodiment of the present invention.
[0023] FIG. 2 shows a plan view of first coded IDT 9.
[0024] FIG. 3 shows a schematic illustration of individual coded
IDT 2.
[0025] FIG. 4 shows a schematic illustration of another
identification card in place of the identification card in FIG.
1.
[0026] FIG. 5 shows a schematic illustration of a still other
identification card in place of the identification card in FIG.
1.
[0027] FIG. 6 shows a schematic illustration of the detail
communication device with the identification card according to a
second embodiment.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY
EMBODIMENTS
[0028] FIG. 1 shows a schematic illustration of a detail
communication device with an identification card, in a recognition
system for identification-card singularity, according to a first
embodiment of the present invention. The recognition system for
identification-card singularity comprises the identification card,
the detail communication device attached to a detail computer, and
a master communication device attached to a master computer. The
identification card comprises first piezoelectric substrate 1,
individual coded IDT 2, first electrode-group 3 consisting of
interdigital electrodes I.sub.0 and interdigital electrode I.sub.1
at the distance L from interdigital electrode I.sub.0, electrode
terminal 4, and electrode terminal 5. Individual coded IDT 2, made
of an aluminum thin film, is formed on first piezoelectric
substrate 1. First electrode-group 3, made of an aluminum thin
film, is formed on first piezoelectric substrate 1, and has an
interdigital periodicity of 40 .mu.m. First piezoelectric substrate
1 is made of a piezoelectric ceramic thin plate with a dimension of
200 .mu.m in thickness. It is possible to use LiNbO.sub.3 and so on
in place of the piezoelectric ceramic plate. The detail
communication device comprises second piezoelectric substrate 6 and
transmitting- and receiving sections. The transmitting section
consists of electrode terminal 7, first bipolar-pulse generator 8,
first coded IDT 9, second coded IDT 10, second electrode-group 11
consisting of interdigital electrode A.sub.0 and interdigital
electrode A.sub.1 at the distance L from interdigital electrode
A.sub.0, setting switch 12, envelope detecting device 13,
monopolar-pulse generator 14, and electrode terminal 15. The
receiving section consists of electrode terminal 16, third
electrode-group 17 consisting of central interdigital electrode
B.sub.0, left interdigital electrode B.sub.-1, and right
interdigital electrode B.sub.1, second bipolar-pulse generator 18,
intermediary IDT 19, third coded IDT 20, fourth coded IDT 21,
detecting device 22, and electrode terminal 23. Left interdigital
electrode B.sub.-1 is at a distance L.sub.0 from central
interdigital electrode B.sub.0. Right interdigital electrode
B.sub.1 is at a distance L.sub.0+L from central interdigital
electrode B.sub.0. First coded IDT 9, second coded IDT 10, second
electrode group 11, third electrode-group 17, intermediary IDT 19,
third coded IDT 20, and fourth coded IDT 21, made of an aluminum
thin film, respectively, are formed on second piezoelectric
substrate 6 made of a piezoelectric ceramic thin plate with a
dimension of 200 .mu.m in thickness. It is possible to use
LiNbO.sub.3 and so on in place of the piezoelectric ceramic plate.
Second electrode group 11, third electrode-group 17, and
intermediary IDT 19 have an interdigital periodicity of 40 .mu.m,
respectively.
[0029] FIG. 2 shows a plan view of first coded IDT 9 consisting of
three interdigital electrode pairs Pi (i=1, 2, and 3), of which two
neighbors are at a distance L from each other. Each pair has an
interdigital periodicity of 40 .mu.m. First coded IDT 9 has a first
coded pattern based on the Baker code. Second coded IDT 10 also
consists of three interdigital electrode pairs, and has a second
coded pattern. Third coded IDT 20 has a third coded pattern in
reverse to the first coded pattern. Fourth coded IDT 21 has a
fourth coded pattern in reverse to the second coded pattern.
Besides a three-digits code (1, 1, 0) as shown in FIG. 2, for
example, a seven-digits code (1, 1, 1, 0, 0, 1, 0), an
eleven-digits code (1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 0), and others
are available.
[0030] FIG. 3 shows a schematic illustration of individual coded
IDT 2. Individual coded IDT 2 is constructed of 16 coded IDTs
classified into A- and B types, which correspond to first coded IDT
9 and second coded IDT 10, respectively. In short, individual coded
IDT 2 has a mixed construction of nine A-type IDTs and seven B-type
IDTs. In other words, individual coded IDT 2 consists of 48
interdigital electrode pairs classified into 16 electrode-pair
groups, and has an individual coded pattern.
[0031] The master communication device corresponding with the
detail communication device in FIG. 1 has the same construction as
the detail communication device in FIG. 1, except for absence of
setting switch 12. Thus, the master communication device comprises
third piezoelectric substrate 6M, electrode terminal 7M, first
bipolar-pulse generator 8M, first coded IDT 9M, second coded IDT
10M, interdigital electrodes A.sub.0M and A.sub.1M, envelope
detecting device 13M directly connected with interdigital
electrodes A.sub.0M and A.sub.1M, monopolar-pulse generator 14M,
electrode terminal 15M, electrode terminal 16M, central
interdigital electrode B.sub.0M, left interdigital electrode
B.sub.1M, right interdigital electrode B.sub.1M, second
bipolar-pulse generator 18M, intermediary IDT 19M, third coded IDT
20M, fourth coded IDT 21M, detecting device 22M, and electrode
terminal 23M. Thus the recognition system for identification-card
singularity has a simple structure with s small size.
[0032] In the recognition system for identification-card
singularity composed of the identification card and the detail
communication device in FIG. 1 and the corresponding master
communication device, if the identification card is set in the
detail communication device, electrode terminal 4 and electrode
terminal 5 are connected at regular intervals with first
bipolar-pulse generator 8 and envelope detecting device 13,
respectively, via setting switch 12. In this time, a pulse
generated at first bipolar-pulse generator 8 is applied to
individual coded IDT 2, so that an individual SAW corresponding to
the individual coded pattern is excited on first piezoelectric
substrate 1. The individual SAW is detected as an individual coded
burst-signal at interdigital electrode I.sub.0, and after a time
corresponding to the distance L, at interdigital electrode I.sub.1
again. The individual coded burst-signals at interdigital
electrodes I.sub.0 and I.sub.1 form an individual double-coded
burst-signal, which arrives at monopolar-pulse generator 14 via
envelope detecting device 13. Thus, an individual double-coded
digital-signal is obtained at monopolar-pulse generator 14. The
individual double-coded digital-signal is composed of an individual
double-coded row of 49 monopolar digital-pulses, of which each is
made from one burst at interdigital electrode I.sub.0 and the
previous burst at interdigital electrode I.sub.1. For example, a
third digital-pulse is based on a third burst at interdigital
electrode I.sub.0 and a second burst at interdigital electrode
I.sub.1. Thus, the individual double-coded digital-signal,
consisting of 49 monopolar digital-pulses in all, is delivered into
a digital network via electrode terminal 15. Moreover, because of
the use of monopolar-pulse generator 14, a monopolar-type
transmission is realized. However, the use of a bipolar-pulse
generator in place of monopolar-pulse generator 14 enables a
bipolar-type transmission superior in transmission ability to the
monopolar-type transmission.
[0033] On the other hand, when the individual double-coded
digital-signal arrives at the corresponding master communication
device, it is received at left interdigital electrode B.sub.-1M and
right interdigital electrode B.sub.1M, respectively, via electrode
terminal 16M. In this time, first- and second SAWs are excited on
third piezoelectric substrate 6M. The first SAW arrives at central
interdigital electrode B.sub.0M by a time corresponding to the
distance L before the second SAW arrives at central interdigital
electrode B.sub.0M. Because both the first- and second SAWs are
composed of a row of 49 burst waves corresponding to the 49
monopolar digital-pulses of the individual double-coded row, one
burst wave of the first SAW and the previous burst wave of the
second SAW consequently arrive at central interdigital electrode
B.sub.0M simultaneously. Thus, a first step of a signal decoding is
achieved. As a result, the individual double-coded digital-signal
is converted into an individual mono-coded burst-signal at central
interdigital electrode B.sub.0M. The individual mono-coded
burst-signal is converted into an individual mono-coded
digital-signal, that is, an individual mono-coded row of
high-frequency bipolar-pulses, at second bipolar-pulse generator
18M. The individual mono-coded digital-signal is applied to
intermediary IDT 19M. And then, a third SAW composed of an
individual coded row of 48 burst-waves, which are classified into
16 burst-wave groups, is excited on third piezoelectric substrate
6M. When the burst-wave group correlates to the third coded
pattern, a first decoded pulse is detected at third coded IDT 20M.
In the same way, when the burst-wave group correlates to the fourth
coded pattern, a second decoded pulse is detected at fourth coded
IDT 21M. Thus, a second step of the signal decoding is achieved. As
a result, an output digital-signal, which is composed of nine first
decoded pulses and seven second decoded pulses and is equivalent to
the individual coded pattern, is detected at electrode terminal 23M
via detecting device 22M without the influence of noises. Thus, the
identification-card singularity is recognized from the output
digital-signal. As a result, the master communication device keeps
on communicating with the detail communication device while the
identification card is set in the detail communication device.
[0034] In addition, double-coded request digital-signal asking for
password is delivered from electrode terminal 15M into the digital
network for further securing such a communication system. In order
to make the double-coded request digital-signal, first of all, a
request digital-signal is applied to first bipolar-pulse generator
8M via electrode terminal 7M, and bipolar pulses (-1 and 1) are
generated at first bipolar-pulse generator 8M. When the bipolar
pulses (-1 and 1) are applied to first coded IDT 9M and second
coded IDT 10M, respectively, fourth- and fifth SAWs corresponding
to the first- and second coded patterns, respectively, are excited
on third piezoelectric substrate 6M. The fourth SAW is detected as
a first coded burst-signal at interdigital electrode A.sub.0M, and
after a time corresponding to the distance L, at interdigital
electrode A.sub.1M, again. The first coded burst-signals at
interdigital electrodes A.sub.0M and A.sub.1M form a first
double-coded burst-signal, which arrives at monopolar-pulse
generator 14M via envelope detecting device 13M. Thus, a first
double-coded digital-signal is obtained at monopolar-pulse
generator 14M. The first double-coded digital-signal is composed of
a first double-coded row of four monopolar digital-pulses, of which
each is made from one burst at interdigital electrode A.sub.0M and
the previous burst at interdigital electrode A.sub.1M. For example,
a third digital-pulse is based on a third burst at interdigital
electrode A.sub.0M and a second burst at interdigital electrode
A.sub.1M. Thus, the first double-coded digital-signal is composed
of four monopolar digital-pulses in all. In the same way, the fifth
SAW is converted into a second double-coded digital-signal at
monopolar-pulse generator 14M. The first- and second double-coded
digital-signals form the double-coded request digital-signal, which
is delivered into the digital network via electrode terminal
15M.
[0035] When the first double-coded digital-signal of the
double-coded request digital-signal is received at electrode
terminal 16 through the digital network, it is applied to left
interdigital electrode B.sub.-1 and right interdigital electrode
B.sub.1, respectively. In this time, first- and second SAWs are
excited on second piezoelectric substrate 6. The first SAW arrives
at central interdigital electrode B.sub.0 by a time corresponding
to the distance L before the second SAW arrives at central
interdigital electrode B.sub.0. Because both the first- and second
SAWs are composed of a row of four burst waves corresponding to the
four monopolar digital-pulses of the first double-coded row, one
burst wave of the first SAW and the previous burst wave of the
second SAW consequently arrive at central interdigital electrode
B.sub.0 simultaneously. As a result, the first double-coded
digital-signal is converted into a first mono-coded burst-signal at
central interdigital electrode B.sub.0. The first mono-coded
burst-signal is converted into a first mono-coded digital-signal,
that is, a first mono-coded row of high-frequency bipolar-pulses,
at second bipolar-pulse generator 18. The first mono-coded
digital-signal is applied to intermediary IDT 19. And then, a third
SAW composed of a first coded row of three burst-waves is excited
on second piezoelectric substrate 6. When the third SAW correlates
to the third coded pattern, a first decoded pulse is detected at
third coded IDT 20. In the same way, if the second double-coded
digital-signal of the double-coded request digital-signal is
received at electrode terminal 16 through the digital network, it
is converted into a second mono-coded digital-signal at second
bipolar-pulse generator 18. The second mono-coded digital-signal is
applied to intermediary IDT 19. And then, a third SAW composed of a
second coded row of three burst-waves is excited on second
piezoelectric substrate 6. When the third SAW correlates to the
fourth coded pattern, a second decoded pulse is detected at fourth
coded IDT 21. As a result, an output digital-signal equivalent to
the request digital-signal is detected at electrode terminal 23 via
detecting device 22 without the influence of noises. In this time,
a password digital-signal is applied to first bipolar-pulse
generator 8 via electrode terminal 7. The password digital-signal
is converted into a double-coded password digital-signal at
monopolar-pulse generator 14, and is delivered into the digital
network via electrode terminal 15. When the double-coded password
digital-signal is received at electrode terminal 16M through the
digital network, it is converted into an output digital-signal
equivalent to the password digital-signal, and is detected at
detecting terminal 23M via detecting device 22M without the
influence of noises.
[0036] FIG. 4 shows a schematic illustration of another
identification card in place of the identification card in FIG. 1.
The identification card in FIG. 4 has the same construction as FIG.
1 except for individual coded IDT 24 and individual coded IDT 25,
which are in place of individual coded IDT 2. Individual coded IDT
24 and individual coded IDT 25 are in uneven parallel with each
other, and located such that the distance between individual coded
IDT 24 and interdigital electrode I.sub.0 is shorter than that
between individual coded IDT 25 and interdigital electrode I.sub.0.
When the pulse generated at first bipolar-pulse generator 8 is
applied to individual coded IDT 24 and individual coded IDT 25,
respectively, first- and second individual SAWs are excited on
first piezoelectric substrate 1. The first individual SAW is
detected as a first individual coded burst-signal at interdigital
electrode I.sub.0, and after a time corresponding to the distance
L, at interdigital electrode I.sub.1 again. The second individual
SAW is detected as a second individual coded burst-signal at
interdigital electrode I.sub.0 just after the first individual
coded burst-signal is detected at interdigital electrode I.sub.0.
And the second individual SAW is detected at interdigital electrode
I.sub.1 again, just after the first individual coded burst-signal
is detected at interdigital electrode I.sub.1. The first- and
second individual coded burst-signals at interdigital electrodes
I.sub.0 and I.sub.1 form a mixed double-coded burst-signal
corresponding to the individual double-coded burst-signal received
at envelope detecting device 13 in FIG. 1.
[0037] FIG. 5 shows a schematic illustration of a still other
identification card in place of the identification card in FIG. 1.
The identification card in FIG. 5 comprises individual coded IDT
26, individual coded IDT 27, interdigital electrodes I.sub.0 and
I.sub.1, and fourth electrode-group 28 consisting of interdigital
electrodes J.sub.0 and J.sub.1. When the pulse generated at first
bipolar-pulse generator 8 is applied to individual coded IDT 26 and
individual coded IDT 27, respectively, first- and second individual
SAWs are excited on first piezoelectric substrate 1. The first
individual SAW is detected as a first individual coded burst-signal
at interdigital electrode J.sub.0, and after a time corresponding
to the distance L, at interdigital electrode J.sub.1 again. The
second individual SAW is detected as a second individual coded
burst-signal at interdigital electrode I.sub.0 just after the first
individual coded burst-signal is detected at interdigital electrode
J.sub.0. And the second individual SAW is detected at interdigital
electrode I.sub.1 again, just after the first individual coded
burst-signal is detected at interdigital electrode J.sub.1. The
first individual coded burst-signals at interdigital electrodes
J.sub.0 and J.sub.1, and the second individual coded burst-signals
at interdigital electrodes I.sub.0 and I.sub.1 form a mixed
double-coded burst-signal corresponding to the individual
double-coded burst-signal received at envelope detecting device 13
in FIG. 1.
[0038] FIG. 6 shows a schematic illustration of the detail
communication device with the identification card according to a
second embodiment. The identification card has the same
construction as FIG. 1, except for further comprising first switch
29, and interdigital electrodes I.sub.2 and I.sub.3, which are
included in first electrode-group 3. A distance between
interdigital electrodes I.sub.1 and I.sub.2, and that between
interdigital electrodes I.sub.2 and I.sub.3 are the same as the
distance L. Interdigital electrodes I.sub.2 and I.sub.3 have an
interdigital periodicity of 40 .mu.m, respectively. The detail
communication device has the same construction as FIG. 1, except
for further comprising second switch 30, third switch 31,
interdigital electrodes A.sub.2 and A.sub.3, included in second
electrode-group 11, and right interdigital electrodes B.sub.2 and
B.sub.3, included in third electrode-group 17. A distance between
interdigital electrodes A.sub.1 and A.sub.2, and that between
interdigital electrodes A.sub.2 and A.sub.3 are the same as the
distance L. Interdigital electrodes A.sub.2 and A.sub.3 have an
interdigital periodicity of 40 .mu.m, respectively. A distance
between right interdigital electrodes B.sub.1 and B.sub.2, and that
between right interdigital electrodes B.sub.2 and B.sub.3 are the
same as the distance L. A distance between central interdigital
electrode B.sub.0 and right interdigital electrode B.sub.2 is
L.sub.0+2L, and that between central interdigital electrode B.sub.0
and right interdigital electrode B.sub.3 is L.sub.0+3L. Right
interdigital electrodes B.sub.2 and B.sub.3 have an interdigital
periodicity of 40 .mu.m, respectively.
[0039] The master communication device corresponding with the
detail communication device in FIG. 6 has the same construction as
the detail communication device in FIG. 6, except for absence of
setting switch 12. Thus, the master communication device comprises
third piezoelectric substrate 6M, electrode terminal 7M, first
bipolar-pulse generator 8M, first coded IDT 9M, second coded IDT
10M, interdigital electrodes A.sub.0M, A.sub.1M, A.sub.2M and
A.sub.3M, second switch 30M, envelope detecting device 13M directly
connected with interdigital electrodes A.sub.0M and second switch
30M, monopolar-pulse generator 14M, electrode terminal 15M,
electrode terminal 16M, third switch 31M, central interdigital
electrode B.sub.0M, left interdigital electrode B.sub.-1M, right
interdigital electrode B.sub.1M, B.sub.2M, and B.sub.3M, second
bipolar-pulse generator 18M, intermediary IDT 19M, third coded IDT
20M, fourth coded IDT 21M, detecting device 22M, and electrode
terminal 23M.
[0040] In the recognition system for identification-card
singularity composed of the identification card and the detail
communication device in FIG. 6 and the corresponding master
communication device, if the identification card is set in the
detail communication device, electrode terminal 4 and electrode
terminal 5 are connected at regular intervals with first
bipolar-pulse generator 8 and envelope detecting device 13,
respectively, via setting switch 12. In this time, a pulse
generated at first bipolar-pulse generator 8 is applied to
individual coded IDT 2, so that an individual SAW corresponding to
the individual coded pattern is excited on first piezoelectric
substrate 1. The individual SAW is detected as an individual coded
burst-signal at interdigital electrode I.sub.0, and after a time
corresponding to the distance L, 2L and 3L, at interdigital
electrodes I.sub.1, I.sub.2, and I.sub.3, respectively. The use of
first switch 29 enables that the individual coded burst-signal at
one of interdigital electrodes I.sub.1, I.sub.2, and I.sub.3
arrives at envelope detecting device 13 via electrode terminal 5.
The individual coded burst-signal at interdigital electrode I.sub.0
and that at one of interdigital electrodes I.sub.1, I.sub.2, and
I.sub.3 form an individual double-coded burst-signal, which arrives
at monopolar-pulse generator 14 via envelope detecting device 13.
Thus, an individual double-coded digital-signal is obtained at
monopolar-pulse generator 14. The individual double-coded
digital-signal is composed of an individual double-coded row of
monopolar digital-pulses, of which each is made from an (n)th burst
at interdigital electrode I.sub.0, and an (n-1)th burst at
interdigital electrode I.sub.1, or an (n-2)th burst at interdigital
electrode I.sub.2, or an (n-3)th burst at interdigital electrode
I.sub.3. For example, a sixth monopolar digital-pulse is based on a
sixth burst at interdigital electrode I.sub.0 and a third burst at
interdigital electrode I.sub.3. Thus, the individual double-coded
digital-signal, consisting of 49, 50 or 51 monopolar digital-pulses
in all, is delivered into a digital network via electrode terminal
15.
[0041] On the other hand, if the individual double-coded
digital-signal arrives at the corresponding master communication
device, it is received at left interdigital electrode B.sub.-1M and
one of right interdigital electrodes B.sub.1M, B.sub.2M, and
B.sub.3M, via electrode terminal 16M. In this time the use of third
switch 31M enables that the individual double-coded digital-signal
arrives at one of right interdigital electrodes B.sub.1M, B.sub.2M,
and B.sub.3M. Thus, a first SAW is excited at left interdigital
electrode B.sub.-1M, and a second SAW is excited at one of right
interdigital electrodes B.sub.1M, B.sub.2M and B.sub.3M, on third
piezoelectric substrate 6M. Central interdigital electrode B.sub.0M
receives the first SAW, and after a time corresponding to the
distance L, 2L or 3L the second SAW. Both the first- and second
SAWs are composed of a row of 49, 50 or 51 burst waves
corresponding to the monopolar digital-pulses of the individual
double-coded row. Therefore, at the same time that an (n)th burst
wave of the first SAW arrives at central interdigital electrode
B.sub.0M, an (n-1)th burst wave of the second SAW at right
interdigital electrodes B.sub.1M, or an (n-2)th burst wave of the
second SAW at right interdigital electrodes B.sub.2M, or an (n-3)th
burst wave of the second SAW at right interdigital electrodes
B.sub.3M consequently arrives at central interdigital electrode
B.sub.0M. For example, a fourth burst wave of the first SAW and a
second burst wave of the second SAW at right interdigital
electrodes B.sub.2M arrive at central interdigital electrode
B.sub.0M simultaneously. As a result, the individual double-coded
digital-signal is converted into an individual mono-coded
burst-signal at central interdigital electrode B.sub.0M. The
individual mono-coded burst-signal is converted into an individual
mono-coded digital-signal at second bipolar-pulse generator 18M.
The individual mono-coded digital-signal is applied to intermediary
IDT 19M, so that a third SAW composed of an individual coded row of
48 burst-waves, which are classified into 16 burst-wave groups, is
excited on third piezoelectric substrate 6M. When the burst-wave
group correlates to the third- and fourth coded patterns,
respectively, first- and second decoded pulses are detected at
third coded IDT 20M and fourth coded IDT 21M, respectively. As a
result, an output digital-signal equivalent to the individual coded
pattern is detected at electrode terminal 23M via detecting device
22M without the influence of noises. Thus, the identification-card
singularity is recognized from the output digital-signal.
[0042] For further securing such a communication system, a
double-coded request digital-signal asking for password is made by
the master communication device. In such a case, first of all, a
request digital-signal is applied to first bipolar-pulse generator
8M via electrode terminal 7M, so that bipolar pulses (-1 and 1) are
generated at first bipolar-pulse generator 8M. When the bipolar
pulses (-1 and 1) are applied to first coded IDT 9M and second
coded IDT 10M, respectively, fourth- and fifth SAWs corresponding
to the first- and second coded patterns, respectively, are excited
on third piezoelectric substrate 6M. The fourth SAW is detected as
a first coded burst-signal at interdigital electrode A.sub.0M, and
after a time corresponding to the distance L, 2L and 3L at
interdigital electrodes A.sub.1M, A.sub.2M, and A.sub.3M,
respectively. The first coded burst-signal at interdigital
electrode A.sub.0M arrives at monopolar-pulse generator 14M via
envelope detecting device 13M. The use of second switch 30M enables
that the first coded burst-signal at one of interdigital electrodes
A.sub.1M, A.sub.2M, and A.sub.3M arrives at monopolar-pulse
generator 14M via envelope detecting device 13M. Thus, a first
double-coded digital-signal is obtained at monopolar-pulse
generator 14M. The first double-coded digital-signal is composed of
a first double-coded row of monopolar digital-pulses, of which each
is made from an (n)th burst at interdigital electrode A.sub.0M, and
an (n-1)th burst at interdigital electrode A.sub.1M, or an (n-2)th
burst at interdigital electrode A.sub.2M, or an (n-3)th burst at
interdigital electrode A.sub.3M. As a result, the first
double-coded digital-signal is composed of four, five or six
monopolar digital-pulses in all. In the same way, the fifth SAW is
converted into a second double-coded digital-signal at
monopolar-pulse generator 14M. The first- and second double-coded
digital-signals form the double-coded request digital-signal, which
is delivered into the digital network via electrode terminal
15M.
[0043] When the first double-coded digital-signal of the
double-coded request digital-signal is received at electrode
terminal 16 through the digital network, it is applied to left
interdigital electrode B.sub.-1, and one of right interdigital
electrodes B.sub.1, B.sub.2, and B.sub.3 via third switch 31. In
this time, a first SAW is excited at left interdigital electrode
B.sub.-1, and a second SAW is excited at one of right interdigital
electrodes B.sub.1, B.sub.2 and B.sub.3, on second piezoelectric
substrate 6. Central interdigital electrode B.sub.0 receives the
first SAW, and after a time corresponding to the distance L, 2L or
3L the second SAW. As a result, the first double-coded
digital-signal is converted into a first mono-coded burst-signal at
central interdigital electrode B.sub.0. Then, the first mono-coded
burst-signal is converted into a first mono-coded digital-signal at
second bipolar-pulse generator 18. The first mono-coded
digital-signal is applied to intermediary IDT 19, so that a third
SAW is excited on second piezoelectric substrate 6. In the same
way, if the second double-coded digital-signal of the double-coded
request digital-signal is received at electrode terminal 16 through
the digital network, it is converted into a second mono-coded
digital_signal at second bipolar-pulse generator 18. When the
second mono-coded digital-signal is applied to intermediary IDT 19,
a third SAW is excited on second piezoelectric substrate 6. If the
third SAW correlates to the third- and fourth coded patterns,
respectively, first- and second decoded pulses are detected at
third coded IDT 20 and fourth coded IDT 21, respectively. As a
result, an output digital-signal equivalent to the request digital
signal is detected at electrode terminal 23 via detecting device 22
without the influence of noises. In this time, a password
digital-signal is applied to first bipolar-pulse generator 8 via
electrode terminal 7. The password digital-signal is converted into
a double-coded password digital-signal at monopolar-pulse generator
14, and is delivered into the digital network via electrode
terminal 15. If the double-coded password digital-signal is
received at electrode terminal 16M through the digital network, it
is converted into an output digital-signal equivalent to the
password digital-signal, and is detected at detecting terminal 23M
via detecting device 22M without the influence of noises.
[0044] While this invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not
limited to the disclosed embodiment, but, on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *