Note: Descriptions are shown in the official language in which they were submitted.
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HULTICHA~EL TYPF HEAD
BACKGROll~D OF THE I~V~TION
_
This inventlon relates to a multichannel magnetic head
of an AC excitation ~ype, and more particularly to a multichannel
magnetic and optical head of a structure comprising optical fibers
arranged in a row on the mul~ichannel magnetic head which can
simultaneously read linearly magnetic pattern and optical pattern
of the same location of an object of detec~ion.
BRI~F DESCRIPTION QF TH~ DRAWI~GS
In the accompanying drawings~
Figure 1 is a view to show the structure of a prior art
AC excitation type magnetic head;
Figure 2 is a view to show an application thereof;
Figure 3 iB a view to show the structure of a prior art
DC excitatlon type magnetic head;
Figures 4 and 5 are views to show examples of detection
with prior art optical sensors, respectively;
Figure 6 is a perspective view to show an embodiment
according to this invention;
Figures 7A and 7B are stxuctural views to show
embodiments of a magnetic head and a cancellation head used for
this invention, respectively;
Figure 8A is a cross sectional view of the embodiment
: shown in Figure 6 at the line X-X, and Figure 8B a cross sec~ional
vlew at the line Y-Y;
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Figure 9 is a block diagram to show the who].e struct~lre
of a magnetic pattern detection system;
Figures lOA through lOF are waveform graphs to show
examples of operation thereof;
Figure 11 is a perspective view to show another
embodiment according to ~his inven~ion;
Fiyure 12A is a cross sectional view of the embodiment
shown in Figure 11 at the llne X-X, and Figure 12B a cross
sectional view at the line Y-Y;
Figure 13A is a plane view to show a head unit while
~lgures 13B is a cross sectional view thereof;
Figures 14 through 16 are views to explaln examples of
arranyement of optical fibers used in this invention;
Figure 17 is a view to explain detection of optical
pattern accorcling to this invention; and
Figures 13 and 19 are views to show other examples of
arrangement of op~ical ~ibers used in this invention.
Maqnetic heads are widely used for reading data recorded
on magnetic card or a tape r or data printed in reading magnetic
ink on a note. The prior art magnetic heads are classified into
two types, i.e. an AC excitation type and a DC excitation type,
and have the following features.
Figure 1 shows an AC excitation type magnetic head 100
comprising a magnetic core 101 of the shape of twin ~ letters of
which central hridge arm 102 is wound with a primary coil 103.
The primary coil 103 is connected to an AC power source 104. The
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magnetic core 10l is wound with the secondary coil 105 on the
upper side thereof and with a cancellation coil 105 on the lower
side thereof. An object 110 of detection such as a note is
adapted to pass above the magnetic core 101.
In the structure above explained, the primary coil 103
is excited with the AC power source 104, and when the object 110
of detection including a magnetic member passes above the upper
surface of the magnetic core 101, signals corresponding to the
magnetic intensity or the pattern of the magnetic member are
outputted from the secondary coil 105. The differenc~
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between the above output and the OUtpllt from the cancellation coil 10~ is
extracted as magnetic si~nals in order to remove noise components and bias
components arising out of fluctuation in the ~C power source 104 and in
temperature characteristic of the magnetic core 101.
Since the prior art AC excitation type magnetic head has the
magnetic core 101 which is wound with both the secondary coil 105 and the
cancellation coil 106 the size of the structure becomes inconveniently big
and when the object 110 as a whole is to be detected simullaneously a
plurality of magnetic heads 100 must be arranged at an interval as shown in
~IG.2. The detection range therefore becomes discrete and ir~capable of
detecting objects at a high precision. This presents a problem in detection
of notes and other ol)jects where hi~hly precise detection is a prerequisite.
IIG.3 shows a DC excitation magnelic head 120 comprising a magne-
tic core 121 of the shape of an inverted letter U and an arm of which is
wound with arl exciting coil 122. The exciting coil 122 is supplied with a
DC constant current I. When the object 110 of detection passes above the
detection head plane diffrrential signals are obtained as detection signals
V in correspondence to the chronological change on the magnetic member
equivalent to the DC component Cllt off by a capacitor 123.
.I The DC excitation magnetic head 120 is detrimental in that as the
detection signal V is obtained as a chronological change on the magnetic
member it cannot detect object which are stationary and moreover in that
the level of detection signals chan~es depending on the relative speed.
Since the DC excitation magnetic head 120 is of a small si~e some systems
have plural heads arranged in a row to cover a wide range. Due to the
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above mentioned fatal defect, the head cannot be applied to the detection of
the magnetic intensity or the ma~netic pattern on notes.
There have been proposed in the prior art other optical sensors
such as those shown in FlGs.~ and 5, respectively. In the optical sensor
shown in FIG.~, the light from a light emitting element 130 is focused by a
lens 131 for projection on a recording medium 132, and the light reflected
from the recording medium 132 is focused on a light receiving element 134
for detection. In the sensor shown in FIG.5, the light from a light
emitting element 135 is focused by a lens 136 for projection on the record-
ing medium 132 and for passing througtl the recording medium 132, and the
transmitted light is focused by a lens 137 for inputting into a light
receiving elcmenL l3~ lo thereby read the pattern defined in optical density
varial:ion on the recordin~ mediuln 132.
~ s the sinlultaneous fornlation of a lnagnetic pattern and an optical
pattern on the recording me(liunl 132 becallle possible in recent years by
mixing nlagrletic powder with print ink, aforementioned Inagnetic sensor and
optical sensor can now be incorporated in one system for reading the magne-
tic pattern and the optical pattern concllrrently. ilowever, the system is
not integrally structured and is incapable of reading the same spot on data
at the same time of the above two types of pattern.
SUMMARY OF TilE IN~'ENTION
This invention was contrived to obviate aforementioned defects
encountered in the prior art, and aims at providing a multichannel type
magnetic head which can precisely detect the magnetic intensity as well as
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magnetic paktern in a wide range of an object simultaneously even
if the object is in a stationary state without dependence on the
relative speed of the object against the magnetic head.
Another object of this invention is to provide a
multichannel type magnetlc and optical head which can detect
magnetic pattern and optical pattern on the same location
simultaneously and effectively.
According to one aspect of this invention, for achieving
the objects described above, there is provided a multichannel type
magnetic head comprising plural magnetic cores arranged in a row
which are wound wi~h primary coils and secondary coils
respectively~ at least one cancellation core which is wound with a
primary coll for cancellation and with a secondary coil for
cancellation, and a member which integrally connect~ said plural
magnetic cores and said at least one cancellation core, wherein
de~e~ion portions of said plural magnetic cores ~re arranged
opposed in a row w~th respect to an object of detection and
wherein said ~t least one cancellation core is disposed
differently from said plural magnetic cores so as to be
unresponsive to said object of detection.
According to another aspect of this invention, there is
provided a multichannel type head comprising an arrangement of
plural magnetic cores which are wound with primary coils and with
secondary coils respectively, and which are provided with gaps at
an interval on detection planes thereof~ at least one cancellation
core which is wound with a primary coil for cancellation and with
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a secondary coil for cancellation, a member which integrally
connects said plural magnetic cores and said at least one
cancellation core, and optieal fibers arranged in each gap wherein
detection portions of said plural magnetic cores and an end of
said optical fibers are opposed in a row with respect to an object
of detec~ion and wherein said at least one cancellation core is
disposed differently from said plural magnetic cores so as to be
unresponsive to said object of detection.
The nature, principle and utility of the invention will
become more apparent from the following detailed description when
read in conjunction with the accompanying drawings.
DETAILED DESCRIPTION OF THE I~VENTION
Figure 6 is a perspective view to show an embodiment of
a multi-channel type magnetic head 10 according to this invention
whereln magnetie heads 11 to 19 as shown in Figure 7A are arranyed
in a row on a detection head plane within a case 1 which is shaped
like a parallelepiped with a domed upper plane. Figure 7A shows
the skructure of a magnetic head 11. Cancellation head 20 is
provided at one end of the detection head plane of the case 1.
Figure 7B shows the structure of the cancellation head 20. Since
the magnetic heads 11 through 19 are of an identical structure, a
magnetic head 11 alone will be described for simplicity's sake by
referring to Figure 7A. The magnetic head 11 has a magnetic core
111 which is shaped like letter U, and arms on both sides thereof
are wound with the primary coil 112 and with ~he secondary coil
113, respectively. The magne~ic head 11 is placed in the case 1
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in a manner th~t a detection plane 114 thereof becomes the
detection head plane of the multichannel type head 10 shown in
Figure 6. The cross
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section along the line X-X in FIG .6 is shown in FIG.~3A.
I'he cancellation head 20 has a structure substantially similar to
the magnetic heads 11 through 19 as shown in FIG.7B wherein a magnetic core
21 shaped like letter ~ has arms on both sides which are wound with the
primary coil 22 for cancellation and with the secondary coil 23 for cancel-
lation respectively and is placed in the case 1 at one end thereof in a
manner that a detection plane 24 of the cancellation head 20 -faces the
direction opposite to the detection head plane of the multichannel type
magnetic head 10 of FIG.6. The cross section of the case along the line Y-Y
in FIG..6 is shown in FIG.~B. The output from the secondary coil 2~ of the
cancellation head 20 is preferably smaller than outputs from the magnetic
hoads 11 through 19. 'I'herefore the winding members of the primary coil 22
and the secondary coil 23 are adjusted in a manrler that the output from the
secondary coil 23 o~ the cancellatiorl head 20 becomes smaller than the
output fronl the secondary coils of respective magnetic heads when they are
driven by the same power source.
As described above nine magnetic heads 11 through 19 and one
cancellation head 20 are arranged in a row and are placed in the case 1
integrally.
The multichannel type magnetic head 10 is driven by a circuit
shown in FIG.9, and magnetic signals M1 through M9 are obtained in multi-
channel in correspondence to the magnetic member of an objec-t of the
detection placed above the detection head plane. More particularly sine
wave S~ of a predetermined frequency outputted from a sine wave oscillator
2 is inputted to constant current boosters 30 through 39 and the constant
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current booster 30 excites the respective primary coils of the magnctic
heads 11 through 19 and the cancellation head 20. The output from the
secondary coil 23 of the cancellation head 20 is inputted to differential
amplifiers 41 through 49 via a buffer amplifier 3 and detection signals S1
through S9 of the secondary coils of the magnetic heads 11 through 19 are
inputted to the differential amplifiers 41 through ~9 respectively. The
difference signals between the detection signals S1 through S9 and the
cancelIation signal CS obtained by the differential amplifiers 41 through 49
are respectively inputted to full-wave rectifying circuits 51 throu~h 59.
The signals rectified in full-wave are inputted to band-pass filters 61
through 69 respectively and at amplifiers 71 through 79 to output magnetic
signals M1 through M9.
The operation in thc circuit of the above structure will be
described referring to the wavef()rnls shown in FIGs.10A through 10F. Since
the operation at the magnetic heads 11 thl^ough 19 are identical to each
other the description will be given only to the magnetic head 11.
The primary coil 112 of the magnetic head 11 is fed with a
constant current of a predetermined frequency from the constant current
booster 31. In correspondence to the magnetic member of the object such as
a note placed to oppose the detection head plane of the multichannel type
magnetic head 10 the detection signal Sl shown in FIG.10A is outputted from
the secondary coil 113 of the magnetic head 11 and inputted to the differ-
ential amplifier 41. In correspondence to the noise component but irrespec-
tive of the magnetic member of the object signals are outputted from the
secondary coil 23 of the cancellation head 20 and are inputted to the
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differential amplifier 41 as the cancellation signal CS shown in ~IG.lOB via
the buffer amplifier 3. The difference signal SlA obtained by differential
amplifier ~1 shown in ~IG.lOC is rectified in full-wave by the full-wave
rectifying circuit 51 as shown in FIGs.lOD and lOE. From this full-wave
rectified signal is extracted envelope by the band-pass filter 61 to output
the magnetic signal M1 from the amplifier 71 which corresponds to the
magnetic member as shown in FIG.lOF.
The example described in the foregoing statement concerns a case
where the magnetic member changes against the time t or, more specifically,
a case where an object of detection moves relative to the multichannel type
magnetic head 10. ~-lowever, this invention detector can obtain magnetic
characteristics o~ an object as magnetic signals even when the object is
standing still. Since one cancellation head 20 is provided against all the
magnetic heads 11 through 1~ to remove the noise components arising out of
variations in tlle sirlt! wave oscillator 2 or in temperature characteristics
from the detet,tion signal component, the magnetic signals can be obtained
with a high detection precision.
Accordingly, as plural AC excitation type magnetic cores are
arranged in a row, and a cancellation core is provided for noise removal,
this invention multichannel magnetlc head can detect the magnetic characte-
ristics as a whole even when the object of detection stays still without
depending on the relative speed of the magnetic member and the magnetic
head. The effect of the noise therefore remains minimal. By sharing one
cancellation coil for noise removal by plural magnetic heads, the whole
structure becomes extremely simplified to thereby achieve a remarkable
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reduction in cost compared to the prior art AC excitation magnetic heads
which are placed in a plural number.
If a sensor comprising optical fibers is provided between gaps in
the multichannel type magnetic heads, it becomes possible to de~ect the
magnetic patterns and the optical patterns at the same position and time.
As shown in FIG.ll, a multichannel type head (a magnetic and optical sensor)
200 is similar to the multichannel type magnetic head lO of FIG.6 in
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appearance and structure. FIGs.12A and 12B show cross-sectional structures
alon~ the line X-X and the line Y-Y respectively. The structure of the
ma~netic cores ll along the line X-X in FIG.ll is shown in FIG.12A in plane
and in FIG.12B in cross section.
A plural.rlulnber of optical fibers 201 for projecting light and a
plural number of optical Eibers 202 for receiving light are arranged in a
gap 114 of the magnetic hcad ll so that the light is proiected on an object
of the detection 110 from ends of the optical fibers 20l and the light
reflected from the object is receivcd and inputted to the ends of the
optical fibers 202. The optical fibers 201 and 202 are similarly arranged
in gaps of magnetic cores 12 through 19 arranged in a row, and ends of the
light proiecting optical fibers 201 are bundled as shown in FIG.14 to
receive light from a light source 203 ( for lnstance" a near infra-red light
emitting diode, a lamp ). The optical fibers 201 and 202 may be plastic
fibers. Out of the optical fibers 201 and 202 arranged for light projection
and for light receiving as shown in FIG.15 in the gap 114, the optical
fibers 202 are fi~ed in layers of rows with a reader head member 204 as
shown in FIG.14. As shown in FIG.16, the optical fibers 202 are further
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opposed to photosensors ( for instance, photodiodes ) 205 in one-to one
relation so that the received li~ht can be detected by each of the photo-
sensors 205 in the unit of a fiber.
Hard glass spacers ( for example, of hard transparent glass,
sapphire glass, optical glass BK7 ) are buried between the ends of the
optical fibers 201 and 202 in the gap 11~. The height of the spacers is
determined in a manner to allo~ sufficient detection of optical patterns.
The cancellation head 20 does not have optical fibers.
As described in the above statement, nine magnetic heads 11
through 19 and one cancellation head 20 are arranged in a row, and the
optical fibers 201 and 202 are placed in the gaps 11~ of the magnetic heads
11 through 19 within the case 1 integrally.
The optical pattern is detected conveniently in parallel to the
process of detectin~ the magnetic pattern, More particularly, the light
froln the light source 203 is transnlitted to the gaps 11~ by the optical
fibers 201, and projected onto the object 110 of detection which is opposed
to the detection head plane as shown in FIG.13. The projected light is
reflected from the surface of the object 110 and inputted to the ends of the
optical fibers 202 for light receiving to thereby optically read the loca-
tion :arked with dia~onal lines llOA in FIC.17 on the object 110. The light
reflected and received from the surface of the object 110 is transmitted via
the optical fibers.202, supplied to the photosensors 205 provided on other
ends, and converted into electric signals correspondin~ to the optical
pattern.
As stated in the above, the ~nagnetic head is structured inte~rally
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with the optical fibers accordin~ to the multichannel type head of this
invention, it can read the magnetic patterns and the optical patterns on the
same location simultaneously in parallel operation.
Although the number of magnetic heads arranged in a row of the
multichannel type head is nine in the above embodiments, the number of
magnetic heads maY be determined arbitrarily. Although one cancellation
head is provided on an end of detection head plane in the above embodiments,
the number of cancellation heads and the position for installing them may be
determined arbitrarily so far as cancellation signals are not affected by
the magnetic member of the object. Moreover, although primary coils of the
magnetic heads and of the cancellation head are excited by sine waves, it
does not necessarily have to be sine waves. It may be rectangular wave.
Although fibers for light projection and optical fibers for receiving light
are arranged in two rows in a gap in the above embodiment, they may be
arranged in one row alternately as shown in i~lG.l~. Alternatively, the
optical fibers for receiving light may be bundled as shown in i~IG.l9.
It should be understood that marly modifications and adaptation of
the invention will become apparent to those skilled in the ar-t and it is
intended to encompass such obvious modifications and changes in the scope of
the claims appended hereto.
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