CA1301314C - Multichannel type head - Google Patents
Multichannel type headInfo
- Publication number
- CA1301314C CA1301314C CA000561300A CA561300A CA1301314C CA 1301314 C CA1301314 C CA 1301314C CA 000561300 A CA000561300 A CA 000561300A CA 561300 A CA561300 A CA 561300A CA 1301314 C CA1301314 C CA 1301314C
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- Prior art keywords
- head
- cancellation
- magnetic
- optical fibers
- detection
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
Sensors are widely used to read magnetic data and to read the magnetic and the optical patterns printed on notes and so on. Since this invention multichannel type head has plural magnetic cores arranged in a row and a cancellation core for noise removal, the head can detect magnetic characteristics as a whole in a stationary state without depending on the relative speed of the magnetic member with the head, and therefore is least affected by noises. Since one cancellation core is shared by plural magnetic cores, the structure as a whole becomes simple, and the manufacture cost can be remarkably reduced. Since a magnetic head is combined with optical fibers in an integral structure according to this invention, it can read the magnetic patterns and the optical patterns on the same location simultaneously by a parallel operation.
Sensors are widely used to read magnetic data and to read the magnetic and the optical patterns printed on notes and so on. Since this invention multichannel type head has plural magnetic cores arranged in a row and a cancellation core for noise removal, the head can detect magnetic characteristics as a whole in a stationary state without depending on the relative speed of the magnetic member with the head, and therefore is least affected by noises. Since one cancellation core is shared by plural magnetic cores, the structure as a whole becomes simple, and the manufacture cost can be remarkably reduced. Since a magnetic head is combined with optical fibers in an integral structure according to this invention, it can read the magnetic patterns and the optical patterns on the same location simultaneously by a parallel operation.
Description
9139D~3~
~7631-4 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;
~ 3~3~L4 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 1 3~L~
27631-~
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~
,,~?~
~ 3~3~4 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 r~., X
~ ;;31D~3~
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 ~ 5/
13~
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 ~3~3~L
27631-~
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 6a -` ~30~3~ ~
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 6b ~ 30~3~
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 ~ 3~3~
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 8 .~
~3~)13~4 , 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 ~ 3~13~L~
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 ~, .
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 ~ 3013~4`
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 ~, .
~' 130~L3~4 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.
.
~7631-4 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;
~ 3~3~L4 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 1 3~L~
27631-~
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~
,,~?~
~ 3~3~4 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 r~., X
~ ;;31D~3~
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 ~ 5/
13~
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 ~3~3~L
27631-~
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 6a -` ~30~3~ ~
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 6b ~ 30~3~
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 ~ 3~3~
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 8 .~
~3~)13~4 , 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 ~ 3~13~L~
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 ~, .
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 ~ 3013~4`
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 ~, .
~' 130~L3~4 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.
.
Claims (13)
1. A multichannel type magnetic head comprising plural magnetic cores arranged in a row which are wound with primary coils and secondary coils respectively, at least one cancellation core which is wound with a primary coil for cancellation and with a secondary coil for cancellation, and a member which integrally connects said plural magnetic cores and said at least one cancellation core, wherein detection portions of said plural magnetic cores are arranged opposed in a row with respect to an object of detection 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.
2. A multichannel type magnetic head as claimed in claim 1, wherein only one of said at least one cancellation core is provided either at an end or at a position midway of said plural magnetic cores.
3. A multichannel type magnetic head as claimed in claim 1, wherein a plurality of said at least one cancellation core are provided at ends of said plural magnetic cores.
4. A multichannel type magnetic head as claimed in claim 1, wherein said at least one cancellation core and said plural magnetic cores are identical in shape and material.
5. A multichannel type magnetic head as claimed in claim 1, wherein the primary coils of said plural magnetic cores and said at least one cancellation core are excited with sine wave signals.
6. 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 a secondary coil for cancellation, a member which integrally connects said plural magnetic cores and said at least one cancellation core, and optical 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 detection 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.
7. A multichannel type head as claimed in claim 6, wherein said optical fibers are divided into those for projecting light and those for receiving light, optical fibers of each type are arranged in a row, and the arrangements of said optical fibers are placed in layers.
8. A multichannel type head as claimed in claim 7, wherein an end of the optical fibers for light projection is led to a light source while an end of the optical fibers for said receiving light is fixed with a reader member.
9. A multichannel type head as claimed in claim 8, wherein photosensors are provided on the side of an end of said optical fibers for receiving light.
10. A multichannel type head as claimed in claim 6, wherein said optical fibers are classified into those for projecting light and those for receiving light, and each type of optical fibers is arranged alternately in one row.
11. A multichannel type head as claimed in claim 6, wherein spacers are provided between said optical fiber ends and said detection portions arranged in said gaps.
12. A multichannel type head as claimed in claim 11, wherein the height of said spacers is determined in a manner to allow sufficient detection of optical patterns.
13. A multichannel type head as claimed in claim 11, wherein hard glass members are burled in said gaps.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP36820/1987 | 1987-03-13 | ||
| JP5682087A JPS63223346A (en) | 1987-03-13 | 1987-03-13 | Air-fuel ratio control device of internal combustion engine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1301314C true CA1301314C (en) | 1992-05-19 |
Family
ID=13038007
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000561300A Expired - Fee Related CA1301314C (en) | 1987-03-13 | 1988-03-11 | Multichannel type head |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS63223346A (en) |
| CA (1) | CA1301314C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1293629B1 (en) * | 1997-07-18 | 1999-03-08 | Magneti Marelli Spa | ELECTRONIC DEVICE FOR CONTROL OF THE AIR/FUEL RATIO OF THE MIXTURE POWERED BY AN ENDothermic Engine. |
-
1987
- 1987-03-13 JP JP5682087A patent/JPS63223346A/en active Pending
-
1988
- 1988-03-11 CA CA000561300A patent/CA1301314C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63223346A (en) | 1988-09-16 |
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| Date | Code | Title | Description |
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| MKLA | Lapsed |