CA1179771A - Perpendicular mode magnetic transducer head - Google Patents
Perpendicular mode magnetic transducer headInfo
- Publication number
- CA1179771A CA1179771A CA000399018A CA399018A CA1179771A CA 1179771 A CA1179771 A CA 1179771A CA 000399018 A CA000399018 A CA 000399018A CA 399018 A CA399018 A CA 399018A CA 1179771 A CA1179771 A CA 1179771A
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- CA
- Canada
- Prior art keywords
- magnetic
- coil
- auxiliary
- main
- magnetic pole
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
- G11B5/1278—Structure or manufacture of heads, e.g. inductive specially adapted for magnetisations perpendicular to the surface of the record carrier
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Magnetic Heads (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A magnetic transducer head having a main magnetic pole formed of a thin film magnetic material having a major surface and facing to a magnetic recording medium at one end thereof, an auxiliary magnetic core provided adjacent to the major surface of the thin film magnetic material having a thickness a along a direction perpendicular to the major surface, an end of the auxiliary magnetic core being remote from the end of the main magnetic pole with a distance ?, a coil wound around the main magnetic pole and the auxiliary magnetic core and at the end of the auxiliary magnetic core, the coil having a thickness b, wherein the a, b and ? are so selected for satisfying that a value (a+ ? )/ ? is not less than 0.55 but not more than 2.4.
A magnetic transducer head having a main magnetic pole formed of a thin film magnetic material having a major surface and facing to a magnetic recording medium at one end thereof, an auxiliary magnetic core provided adjacent to the major surface of the thin film magnetic material having a thickness a along a direction perpendicular to the major surface, an end of the auxiliary magnetic core being remote from the end of the main magnetic pole with a distance ?, a coil wound around the main magnetic pole and the auxiliary magnetic core and at the end of the auxiliary magnetic core, the coil having a thickness b, wherein the a, b and ? are so selected for satisfying that a value (a+ ? )/ ? is not less than 0.55 but not more than 2.4.
Description
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PERPENDICULAR MODE r~NElIC TR~SDUCER HEAD
B.~CKGROUN~ OF THE INVENTION
__ ______ _ ___ Field of the Invention Ihe present invention relates generally to a magnetic transducer head and is directed more particularly to a magnetic transducer head for use with a so-called perpendicular or vertical magnetization mode recording.
Description of the Prior Art To record a high frequency (short wavelength) signal on a magnetic recording tape, it is known that a so-called perpendicular or vertical magnetization mode recording is more advantageous than a so-called longitudinal magnetization mode recording, in which the former utilizes a magnetization along a direction perpendicular tc a major plane o~ the magne~ic recording tape, while the latter utilizes a magnetization along a major plane of a magnetic tape. This is because a self-demagnetizing field in a magnetic layer of the magnetic recording tape becomes smaller in the perpendicular magnetization mode recording when a wavelength of a recording signal becomes shorter, while the self-demagneti2ing field becomes larger in the longitudinal magnetization mode recording.
For the magnetic transducer head utilized for this vertical magnetization mode recording, various ones have been proposed. T~ perform its recording ~or magnetizing the magnetic recording layer of the magnetic tape) ideally or perfectly in the vertical magnetization mode recording, a main component of the magnetic field originated from the magnetic transd~cer head has to be as vertical as possible to a ~ ~977~
magnetic recording medium such as a ~u~.
One example of the magnetic transducer head is shown as h in Fig. 1 in which a main magnetic pole 2 formed of a thin film of magnetic material having high permeability such as permalloy and an auxiliary magnetic pole 3 are provided across a magnetic recording medium 1 so as to oppose to each ~ther. A coil 4 is wound around this auxili-ary magnetic pole 3.
In this case, however, the auxiliary magnetic pole 3 has to be placed at the opp~site side from the main magnetic pole 2 with respect to the magnetic recording medium 1 and adjacent to the magnetic recording medium, which, as a result, causes difficulties in assembling and handling such as loading of the magnetic recording medium 1 between the main magnetic pole 2 and the auxiliary magnetic pole 3.
To avoid these drawbacks, it is proposed to use a magnetic recording medium 1, as shown in Fig. 2, which is formed of a non-magnetic base 5 and a layer of high permea-bility material 6 formed on the non-magnetic base 5 and a magnetic recording layer 7 formed on the layer of high permeability material 6. In this case, when a single pole type magnetic head h formed of a thin film of soft magnetic material is provided to oppose the magnetic recording layer 7 and a signal is applied to the winding 4 wound around the pole 2 so as to record the signal, satisfactory recording sensitivity and excellent recording characteristic can be achieved.
The main magnetic pole 2 of the magnetic transducer head h of this kind is formed of a thin film of ferromagnetic mate~ia~ such as per~loy, Fe-A~-Si system alloy, a so-called 1~977~
Sendust alloy of about 0.5 to 3 ~m thick. The coil 4 to magnetically excite the thin film main magnetic pole 2, namely, the recording winding can be formed of a thin film coil which is bonded through an insulating film such as SiO2, AQ2O3, Si3N4 or the like around the vicinity of the top of the thin film magnetic pole 2. In this case, to excite the main magnetic pole 2 through the use of the coil 4 efficiently, it is desirable that the front end of the coil 4 is placed so as to coincide with the top of the main magnetic pole 2 which faces the sliding surface of the magnetic recording medium 1. But, when the coil 4 is located at the front end thereof facing the sliding surface of the magnetic recording medium 1, the coil 4 will be short -circuited by the magnetic recording medium 1 when the magnetic recording layer 7 has conductivity. Even if the surface of the magnetic recording layer is formed of an insulating material, there is a substantial chance of short -circuit of the coil 4, since the coil is usually formed of a relatively soft material such as copper, aluminum, silver, gold and so on, then the coil is apt to be extended to bridge between turns of the coil with each other by rubbing of the magnetic recording medium. Also, when the coil 4 closely faces the magnetic recording medium 1 as described above, a magnetic field produced from the coil 4 is directly given to the magnetic recording medium 1 in addition to the recording magnetic field applied through the main magnetic pole 2. The range or area of the magnetic field macle by the coil 4 is so widely spread that the recording magnetic field, which will be applied to the magnetic recording medium 1, is forced to be spread thus the high density recording being obstructed.
I l~g~7~
Such drawbacks can be avoided by p~oviding the exciting coil4remote from the end of the main pole 2 which faces the magnetic recording medium, that is, a spacing is provided between the top of the exciting coil and the end of the main magnetic pole. By providing the spacing, direct contact of the exciting coil to the magnetic recording medium can be avoided. In addition, the magnetic field qenerated by the exciting coil at the magnetic recording medium decreases abruptly as the spacing increases.
On the contrary, if the exciting coil 4 is provided at a spacing from the magnetic recording medium, although the portion of the main magnetic pole 2 around which the winding 4 is provided is strongly magnetized, the magnetization level at the end of the main magnetic pole 2 protruded from the portion around which the winding of the coil 4 is provided is rapidly decreased. This is mainly because the exciting coil 4 is wound nearly tight around the main magnetic pole 2, the diameter of the coil 4 wound therearound is relatively selected to be small, then the magnetic field originated by the coil is decreased suddenly at the portion remote from the end of the coil, and the main magnetic pole 2 is formed of the thin film having magnetic resistance and so on.
~ig. 3 shows the relationship between a position in the main magnetic pole 2, and the magnetic flux density By along an axis of the main magnetic pole, in which the abscissa represents the position along a direction y,that is,the axis of the main magnetic pole 2, and the ordinate represents the magnetic flux density By along the direction y. The solid line ~ indicates a distribution of By of the magnetic trans-3~ ducer head in which the exciting coil is so wound nearly tight I ~ 7977~
on the main magnetic pole that the main magnetic pole is protruded from the top of the exciting coil for 50~. The broken line 9 indicates the magnetic flux density By when the main magnetic pole is excited in a parallel magnetic field instead of the exciting coil 4 wound on the pole.
As apparent from the curve 8, the magnetization at the top of the main magnetic pole 2 protruded from the coil 4 is decreased abruptly. Whereas, as shown by the curve 9 in Fig. 3, the main magnetic pole 2 is excited fully up to its end by the parallel magnetic field. Accordingly, it is desired that the main magnetic pole 2 is excited based upon the parallel magnetic field. To achieve such parallel magnetic field, the winding diameter of the coil 4 must be enlarged. But, if the winding diameter of the coil 4 is enlarged as described above, the recording efficiency is deteriorated and large recording current is required.
To improve such disadvantage, as shown in Fig. 4, it is considered that an auxiliary core 10 formed of high permeability material may be placed so as to be attached to one surface or both surfaces of the thin film main magnetic pole 2 so as to protrude the main magnetic pole, in other words, the auxiliary cores are provided remote from the sliding surface with the magnetic recording medium 1. ~n this case, it is apparent tha-t the recording efficiency will be enhanced more when the exciting coil 4 is wound around the vicinity of the top of the auxiliary core 10 as near as possible to the top.
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OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a magnetic transducer head for use with vertical magnetization mode recording.
lt is another object of the present invention to provide a magnetic transducer head for use with vertical magnetization mode recording of high recording efficiency.
It is a further object of the present invention to provide a magnetic transducer head structure to efficiently magnetize a single pole magnetic core.
According to one aspect of the present invention, there is provided a magnetic transducer head having a main magnetic pole formed of a thin film magnetic material having a major surface and facing to a magnetic recording medium at one end t~ereof, an auxiliary magnetic core provided adjacent to the major surface of the thin film magnetic material having a thickness a along a direction perpendicular to the major surface, an end of the auxiliary magnetic core being spaced from the end of the main magnetic pole with a distance Q, a coil wound around the main magnetic pole and the auxiliary magnetic core and at the end of the auxiliary magnetic core, the coil having a thickness b, wherein the a, b and Q are selected for satisfying that a value (a + b2)/Q is not less than 0.5~ ~ut not more than 2.4.
The other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings thro~h which t~e like references designate the same elements and parts.
i 17~771 BRIEF DESCRIPTION OF THE DRAWINGS
Figs. 1, 2 and 4 are respectively diagrams each schematically showing a prior art magnetic transducer head for use with vertical magnetization mode recording;
Fig. 3 shows a relationship between a magnetic flux density in a main magnetic pole and a position in the pole;
Figs. 5, 6 and 10 are respectively diagrams each schematically showing examples of a magnetic transducer head according to the present invention;
Figs. 7, 8 and 9 are graphs to explain the present invention; and Figs. 11 through 17 are schematic illustrations showing manufacturing steps of the magnetic transducer head of the present invention.
DESCRIPTION OF THE PREFERRED RMBODIMENTS
The inventors clarified that in the magnetic -trans-ducer head having such auxiliary core, a magnitude of magnetic field for the recording a-t the -top portion of the main magnetic pole depended upon a magnitude of the exci-ting magnetic field at -the top of the main maynetic pole, in other words, a magnitude of a magne-tic field at the top of the main magnetic pole when the main magnetic pole was removed but instead, the auxiliary core around which the coil is wound exists alone.
Therefore, to record the signal on the magnetic recording medium most efficiently, it should be arranged to 7 7 i generate the strongest magnetic field at the top of the main magnetic pole, when a predetermined current is applied to the exciting coil. Generally, as the diameter of the coil wound becomes large, the attenuation of the magnetic field at the position remote from the coil on the central axis of the coil becomes small. On the other hand, the magnetic field on the central axis of the coil becomes smaller when the winding diameter of the coil becomes larger.
Accordingly, it is necessary to consider the arrangement of the coil, the position of the coil wound on -the core, the diameter of the coil and so on properly, to maximize the exciting magnetic field.
On the basis of the above-mentioned consideration and clarification and further with various experiments and discussious, the inventors propose a magnetic transducer head for use in vertical magnetization mode recording with high recording efficiency.
Now, embodiments of the magnetic transducer head according to the present invention will be described with reference to Fig. 5 and the following drawings in which like references corresponding to those of Figs. 1,2 and 4 designate the same elements and parts.
In the figures, reference letter H denotes an overall arrangement of a magnetic transducer head according to the present invention.
In the embodiment of the present invention, as shown in Fig. 5 or 6 by way of example, there is provided the main magnetic pole 2 formed of a thin film of magnetic material made of, for example, permalloy, Sendust alloy and so on of about 0.5 to 3 ~m thick, a thickness of which is ~ 7 797~ ~
represented by letter t in the figure. On both surfaces or one surface of the main magnetic pole 2 is magnetically bonded tight an auxiliary core or cores 10 formed of high permeability material such as Mn- Zn ferrite, Ni- Zn ferrite or the like. This auxiliary core 10 is placed in such a manner that the top thereof may be located at the position farther back from the top of the main magnetic pole 2 facing the slidiny surface of the magnetic recording medium (not shown) along which the main magnetic pole 2 slides by a distance Q.
The coil 4 is placed on this auxiliary magnetic core 10 in such a manner as to wrap both the auxiliary magnetic core 10 and the main magnetic pole 2 sandwiched therebetween. ~ore precisely, the coil 4 is placed on the auxiliary magnetic core 10 as near as possible to the end of the auxiliary core, so that the top surface thereof may be coincident with the top surface of the auxiliary magnetic core 10, which is then wound therearound by, for example, a winding of a conductive wire.
Now, let us take a thickness of the auxiliary core as _, that is, a distance from one surface of the main magnetic pole to which a surface of the auxiliary magnetic pole abut to the inner surface of the coil, and a winding thickness of the coil 4 as b. In this invention the above defined dimensions, Q, a and _ are selected to satisfy a relation that (a + b2 )/Q is not more than 2.4 but not less than 0.55 under the practical dimension of Q ranging from 10 to 200 ~Im. The reason why the distance Q is selected as described above is based upGn the results shown in Figs. 7 and 8 in which the magnetic field in the axial direction 1 1~97~:~
component at the top of the main magnetic pole 2 is examined when the value of (a + 2 )/Q is changed in the magnetic transducer head, a construction o~ which is shown in Figs.
5 and 6. In Figs. 7 and 8, the magnetic field is expressed as a relative value when the maximum value thereof is taken as 100% . In Fig. 7, curves 11, 12 and 13 each describe the case where the positions of the tops of the paired auxi-liary magnetic cores 10, which are located symmetrically to grip the main magnetic pole 2 therebetween as shown in Fig. 5, are selected such that the distance Q between the tops of the main magnetic pole 2 and the auxiliary magnetic core 10 may change as 30 ~m, 50 ~m and 100 ~m, respectively. Also, curves 14, 15 and 16 of E`ig. 8 describe the case in which the position of the top of the auxiliary magnetic core 10 located at one side of the main magnetic pole 2 as shown in Fig. 6 is selected such that the distance Q between the tops of the main magnetic pole 2 and the auxiliary core 10 may change as 30 ~m, 50 ~m and 100 ~m, respectively. In this case, Fig. 8 shows a distribution of the magnetic field in which the spacing _ where no auxiliary magnetic core is provided is selected equal to the distance a.
Turning back to Fig. 7, it is understood that the magnetic field becomes strongest when (a + b2 )/Q is 1.3, the magnetic field decreases by about ~2 % (+1 %)of the maximum value when (a+ b2 )/Q,is in a range from 0.8 to 2.0 and it decreases by -4 ~ (~2 %) of -the maximum value when (a + b )/Q
is in a range from 0.65 to 2.4. Also, with reference to Fig.
8, the magnetic field becomes strongest when (a+ b2 )/Q is 1.22, it decreases by about - 2 % (+1 %) of the maximum value when (a + 2 )/Q is in a range from 0.7 to 2.0 and it decreases 7~
by -4 ~ ( ~ 2%) of the maximum value when ta ~ b2 )/~ is in a range from 0.55 to 2.42. Comparing the representations in Fig. 7 with those of Fig. 8, an tendency of how the top of the main magnetic pole 2 influences the magnetic field is nearly equal in both cases where the auxiliary magnetic core 10 is provided at both surfaces of the main magnetic pole 2 and where it is provided on the one surface thereof as shown in Figs. 5 and 6. From Figs. 7 and 8, it is understood that the magnetic field at the top of the main 1~ magnet~c pole 2 is effectively enhanced if (a+ b2 )/~ is in the range from 0.55 to 2.4, which is why the range of (a+ b2 )/Q is selected to be from 0.55 to 2.4.
In the case, as shown in Fig. 6, when the auxiliary core 10 is placed at one side surface of the main magnetic 15 . pole 2, the similar magnetic field at the top of the main magnetic pole 2 is measured while the distance d from the other side surface of the main magnetic pole 2, which the auxiliary core 10 is not attached to, to the inner surface of the coil 4 opposing thereto is selectively changed with the results shown in Fig. 9. In this case, Q is selected as 50 ~m, a is selected as 50 ~m and _ is selected as 20 ~m. In addition, the length c of the coil 4 is selected as 50 ~m.
As it will be clear from Fig. 9, the magnetic field at the top of the main magnetic pole 2 becomes larger if d > b is established. Thus, when the auxiliary magnetic core 10 is placed on one side of the main magnetic pole 2, it is desired to select the relationship between the lengths d and _ so as to satisfy d ~ b.
The depth oi ~he coil 4, namely, the size represented 3ti by the letter c in Figs. 5 and ~ does not influence the recordin~
7 ~ 1 efficiency so much. But, if the depth c is too much large as compared with the thickness _, this is not preferable because it causes the recording efficiency to be lowered.
Therefore, the value of c/b must be selected to be 5 or below, particularly, for example, less than about 2 to 3.
While in the auxiliary core 10, the distance a is selected at its top side where the coil 4 is wound such that (a + b2 )/Q becomes in a range from 0.55 to 2.4, the thickness at its rear end side later than the por-tion around which the coil 4 is wound can be increased in consideration of its mechanical s-trength.
Fig. 10 illustrates an example of such case in which each of reinforcing members 17 formed of non magnetic material such as Zn ferrite is further bonded to the top of the auxi-liary magnetic core 10 so as to extend to and grip the top of the main magnetic pole 2 to thereby enable the top of the main magnetic pole 2 to be reinforced.
IE the auxiliary core 10 is formed on one side of the main magnetic pole 2, the reinforcing member 17 provided on the side where the auxiliary magnetic core 10 is not provided is extended backward or downward so as -to uni-te it with the main magnetic pole 2, whereby the coil 4 can be wound around both this reinforcing member 17 extended and the auxi-liary magnetic core 10 on the other side of the main magnetic pole 2.
sy way of example, the sizes of the respective parts of the magnetic transducer head H whose structure is shown in Fig. 10 are enumerated below. _ is 100 ~Im, a is 150 ~m, b is_ 50 ~m and _ is 1.5 mm. In addition, the thickness of the rear par-t of the auxiliary magnetic core 10, the thickness of ~ ~7977~
which is large and shown by e in Fig. 10 can be selected as 1 mm and the length thereof, which is designated by f, can be selected as 4 mm.
In this case, the magnetic recording medium 1 whose layer of high permeability material 6 is formed of permalloy layer of 0.5 ~m thick and whose magnetic recording layer 7 is formed of Co - Cr alloy layer of 0.5 ~m thick may be utiliæed.
An example of a method for producing a magnetic transducer head according to the present invention will next be described in detail with reference to Fig. 11 and the following drawings.
First, as shown in Fig. 11, a joint body 30 is prepared by bonding a rectangular shape block of magnetic material 20 and a plate shape block of non-magnetic material 270 The block of magnetic material 20 may be formed of Mn - Zn ferrite or Ni - Zn ferrite, and the block of non-magnetic material may be formed of glass, ceramics, non-magnetic Zn ferrite and so on. However, it is desired that both of the magnetic and the non-magnetic materials have similar thermal expansion coefficient with each other, thus it is preferred that the magnetic and non-magnetic blocks 20, 27 are formed of magnetic and non-magne-tic ferrite, respectively. The magnetic material block 20 and the non-magnetic material block 27 can be bonded together through the use of melt bonding of glass, water glass, organic adhesive, such as epoxy resin, or inorganic adhesive.
Next, the joint body 30 made of the magnetic material block 20 and the non-magnetic material block 27 is cut out along surfaces shown by two-dots chain lines ml, m2, ~ ~L7!~'7~
m3, in Fig. 11 to provide a plurali-ty of plate members 31, each having a predetermined thickness as illustrated in Fig. 12.
In Fig. 12, a major surface 31a which stretches over the magnetic material memher 20 and -the non magne-tic member 27 composing the plate member 31 is polished to have a mirror finish. An insulating layer 32 made of such as SiO2, Si3N4, AQ2O3 or the like is formed on this major surface 31a on which a thin film magne-tic material layer 22 made of, for example, permalloy, Sendust alloy and so on of 0.5 to 3 ~m thick is formed by vacuum evapolation, sputtering or the lik~.
Next, as illustrated in Fig. 13, the thin film magnetic material 22 is selectively removed by using a photolithography technique to leave band-shaped portions 22', 22", , which are placed in parallel to each other with a predetermined width and spacing. The portions between the band shape thin film 22, 22" are filled in with non -magnetic material 34 to form a flush surface with the surface of thin film bands of magnetic material. In addition, materials such as SiO2, Si3N4 and AQ2O3 or -the like may be formed thereon.
On the other hand, as shown in Fig. 14, other plate member 31', which is cut away Erom the same joint body 30 as described previously in Fig. 11 whic}l is formed of the maynetic material member 20 and the non-magnetic member 27, is prepared. A major surface 31a' thereof is likewise polished to make a mirror finish and as shown in Fig. 14, this major surface 31a' is bonded to the surface side of the plate member 31 on which the thin film maynetic material 22 and the ~ ~79~1 non-magnetic layer 34 are formed as shown in Fig. 13. In this case, a recess or notch 35 is formed in advance on the major surface 31a' of the plate member 31' by, for example, etching and an adhesive 36 is filled or charged into this S notch 35, both the plate members 31 and 31' can be bonded with one another strongly.
If necessary, as illustrated in Fig. 15, the external surfaces of both the plate members 31 and 31' are cut away at the side of the non magnetic member 27, the respective thicknesses of which are selected to be smaller than those of the remaining parts. As shown by two-dots chain lines nl, n2, , in Fig. 15, the bonded plates 31 and 31' are cut away to include the respective band-shaped thin film of magnetic materials 22', 22", , the top surfaces each are ground or polished so as to construct a sliding surface S with the magnetic recording medium (not shown) as illustrated in Fig. 16.
Thus, the magnetic transducer head H according to the present invention can be manufactured in which the thin film main magnetic pole 2 made of thin film magnetic material 22 is provided to abut the sliding surface S for the magnetic recording medium, the reinforcing members 17 formed of the non magnetic member 27 are placed on both sides of the main magnetic pole 2 at the vicil~ity of the top thereof and the auxiliary cores 10 formed of the magnetic recording member 20 are placed behind the reinforcing member 17.
In this case, when the non-ma~netic material 3~ arc located adjacent to -the main magnetic pole 2, a spacing or gap between both of the reinforcing members 17 on both sides of the main magne-tic pole 2 abutting against the sliding ~ ~7~
surface s ~or the magnetic recording medium is almost filled by the non-magnetic material 34 so that an amount of adhesive which will be filled into the aforesaicd gap is made less, in other words, the area abutting the sliding surface S for the magnetic recording medium in which the adhesive is used is reduced to be less than that of the case where the non-magnetic material 34 is not provided. Thus, an occurrence of head clogging caused by the fact that much adhesive abuts against the sliding surface S can be reduced.
This magnetic transducer head lI is wound by -the coil 4 around its thin portion in the position at which it is moved farther back than the sliding surface S. In this case, even in the magnetic transducer head H thus constructed, a relationship for dimension and arrangement between the re-spective parts thereof is selected as described previously.
Also, this magnetic transducer head H is attached to, as, for example, shown in Fig. 17, a head holder 43 through which each of apertures 41 is bored to attach the same on a rotary drum of a VTR (video tape recorder) and on which each of conductive terminal patterns 42 is bonded. Each terminal end of the coil 4 a-t the magnetic transducer head H is con-nected electrically to each conductive terminal pattern 42 through soldering, by way of example.
~s described above, according -to the magnetic transducer head of the present invention, although the coil 4 is placed farther bac~ than the sliding surface S for the magnetic recording medium, the recording efficiency is high.
~lso, it is obvious that the same effect can be achieved if the magnetic transducer head according to the present invention is also applied for a magnetic transducer ~ 1797~
head of a multi-elements type in which a plurality oE main magnetic poles 2 are placed.
The above description is given on the preferred embodiments of the invention, but it will be apparent that many modifications and variations could be effected by one skilled in the art without departing from the spirits or scope of the novel concepts of the invention, so that the scope of the invention should be determined by the appended claims only.
PERPENDICULAR MODE r~NElIC TR~SDUCER HEAD
B.~CKGROUN~ OF THE INVENTION
__ ______ _ ___ Field of the Invention Ihe present invention relates generally to a magnetic transducer head and is directed more particularly to a magnetic transducer head for use with a so-called perpendicular or vertical magnetization mode recording.
Description of the Prior Art To record a high frequency (short wavelength) signal on a magnetic recording tape, it is known that a so-called perpendicular or vertical magnetization mode recording is more advantageous than a so-called longitudinal magnetization mode recording, in which the former utilizes a magnetization along a direction perpendicular tc a major plane o~ the magne~ic recording tape, while the latter utilizes a magnetization along a major plane of a magnetic tape. This is because a self-demagnetizing field in a magnetic layer of the magnetic recording tape becomes smaller in the perpendicular magnetization mode recording when a wavelength of a recording signal becomes shorter, while the self-demagneti2ing field becomes larger in the longitudinal magnetization mode recording.
For the magnetic transducer head utilized for this vertical magnetization mode recording, various ones have been proposed. T~ perform its recording ~or magnetizing the magnetic recording layer of the magnetic tape) ideally or perfectly in the vertical magnetization mode recording, a main component of the magnetic field originated from the magnetic transd~cer head has to be as vertical as possible to a ~ ~977~
magnetic recording medium such as a ~u~.
One example of the magnetic transducer head is shown as h in Fig. 1 in which a main magnetic pole 2 formed of a thin film of magnetic material having high permeability such as permalloy and an auxiliary magnetic pole 3 are provided across a magnetic recording medium 1 so as to oppose to each ~ther. A coil 4 is wound around this auxili-ary magnetic pole 3.
In this case, however, the auxiliary magnetic pole 3 has to be placed at the opp~site side from the main magnetic pole 2 with respect to the magnetic recording medium 1 and adjacent to the magnetic recording medium, which, as a result, causes difficulties in assembling and handling such as loading of the magnetic recording medium 1 between the main magnetic pole 2 and the auxiliary magnetic pole 3.
To avoid these drawbacks, it is proposed to use a magnetic recording medium 1, as shown in Fig. 2, which is formed of a non-magnetic base 5 and a layer of high permea-bility material 6 formed on the non-magnetic base 5 and a magnetic recording layer 7 formed on the layer of high permeability material 6. In this case, when a single pole type magnetic head h formed of a thin film of soft magnetic material is provided to oppose the magnetic recording layer 7 and a signal is applied to the winding 4 wound around the pole 2 so as to record the signal, satisfactory recording sensitivity and excellent recording characteristic can be achieved.
The main magnetic pole 2 of the magnetic transducer head h of this kind is formed of a thin film of ferromagnetic mate~ia~ such as per~loy, Fe-A~-Si system alloy, a so-called 1~977~
Sendust alloy of about 0.5 to 3 ~m thick. The coil 4 to magnetically excite the thin film main magnetic pole 2, namely, the recording winding can be formed of a thin film coil which is bonded through an insulating film such as SiO2, AQ2O3, Si3N4 or the like around the vicinity of the top of the thin film magnetic pole 2. In this case, to excite the main magnetic pole 2 through the use of the coil 4 efficiently, it is desirable that the front end of the coil 4 is placed so as to coincide with the top of the main magnetic pole 2 which faces the sliding surface of the magnetic recording medium 1. But, when the coil 4 is located at the front end thereof facing the sliding surface of the magnetic recording medium 1, the coil 4 will be short -circuited by the magnetic recording medium 1 when the magnetic recording layer 7 has conductivity. Even if the surface of the magnetic recording layer is formed of an insulating material, there is a substantial chance of short -circuit of the coil 4, since the coil is usually formed of a relatively soft material such as copper, aluminum, silver, gold and so on, then the coil is apt to be extended to bridge between turns of the coil with each other by rubbing of the magnetic recording medium. Also, when the coil 4 closely faces the magnetic recording medium 1 as described above, a magnetic field produced from the coil 4 is directly given to the magnetic recording medium 1 in addition to the recording magnetic field applied through the main magnetic pole 2. The range or area of the magnetic field macle by the coil 4 is so widely spread that the recording magnetic field, which will be applied to the magnetic recording medium 1, is forced to be spread thus the high density recording being obstructed.
I l~g~7~
Such drawbacks can be avoided by p~oviding the exciting coil4remote from the end of the main pole 2 which faces the magnetic recording medium, that is, a spacing is provided between the top of the exciting coil and the end of the main magnetic pole. By providing the spacing, direct contact of the exciting coil to the magnetic recording medium can be avoided. In addition, the magnetic field qenerated by the exciting coil at the magnetic recording medium decreases abruptly as the spacing increases.
On the contrary, if the exciting coil 4 is provided at a spacing from the magnetic recording medium, although the portion of the main magnetic pole 2 around which the winding 4 is provided is strongly magnetized, the magnetization level at the end of the main magnetic pole 2 protruded from the portion around which the winding of the coil 4 is provided is rapidly decreased. This is mainly because the exciting coil 4 is wound nearly tight around the main magnetic pole 2, the diameter of the coil 4 wound therearound is relatively selected to be small, then the magnetic field originated by the coil is decreased suddenly at the portion remote from the end of the coil, and the main magnetic pole 2 is formed of the thin film having magnetic resistance and so on.
~ig. 3 shows the relationship between a position in the main magnetic pole 2, and the magnetic flux density By along an axis of the main magnetic pole, in which the abscissa represents the position along a direction y,that is,the axis of the main magnetic pole 2, and the ordinate represents the magnetic flux density By along the direction y. The solid line ~ indicates a distribution of By of the magnetic trans-3~ ducer head in which the exciting coil is so wound nearly tight I ~ 7977~
on the main magnetic pole that the main magnetic pole is protruded from the top of the exciting coil for 50~. The broken line 9 indicates the magnetic flux density By when the main magnetic pole is excited in a parallel magnetic field instead of the exciting coil 4 wound on the pole.
As apparent from the curve 8, the magnetization at the top of the main magnetic pole 2 protruded from the coil 4 is decreased abruptly. Whereas, as shown by the curve 9 in Fig. 3, the main magnetic pole 2 is excited fully up to its end by the parallel magnetic field. Accordingly, it is desired that the main magnetic pole 2 is excited based upon the parallel magnetic field. To achieve such parallel magnetic field, the winding diameter of the coil 4 must be enlarged. But, if the winding diameter of the coil 4 is enlarged as described above, the recording efficiency is deteriorated and large recording current is required.
To improve such disadvantage, as shown in Fig. 4, it is considered that an auxiliary core 10 formed of high permeability material may be placed so as to be attached to one surface or both surfaces of the thin film main magnetic pole 2 so as to protrude the main magnetic pole, in other words, the auxiliary cores are provided remote from the sliding surface with the magnetic recording medium 1. ~n this case, it is apparent tha-t the recording efficiency will be enhanced more when the exciting coil 4 is wound around the vicinity of the top of the auxiliary core 10 as near as possible to the top.
t 1~9~.'7:L
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a magnetic transducer head for use with vertical magnetization mode recording.
lt is another object of the present invention to provide a magnetic transducer head for use with vertical magnetization mode recording of high recording efficiency.
It is a further object of the present invention to provide a magnetic transducer head structure to efficiently magnetize a single pole magnetic core.
According to one aspect of the present invention, there is provided a magnetic transducer head having a main magnetic pole formed of a thin film magnetic material having a major surface and facing to a magnetic recording medium at one end t~ereof, an auxiliary magnetic core provided adjacent to the major surface of the thin film magnetic material having a thickness a along a direction perpendicular to the major surface, an end of the auxiliary magnetic core being spaced from the end of the main magnetic pole with a distance Q, a coil wound around the main magnetic pole and the auxiliary magnetic core and at the end of the auxiliary magnetic core, the coil having a thickness b, wherein the a, b and Q are selected for satisfying that a value (a + b2)/Q is not less than 0.5~ ~ut not more than 2.4.
The other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings thro~h which t~e like references designate the same elements and parts.
i 17~771 BRIEF DESCRIPTION OF THE DRAWINGS
Figs. 1, 2 and 4 are respectively diagrams each schematically showing a prior art magnetic transducer head for use with vertical magnetization mode recording;
Fig. 3 shows a relationship between a magnetic flux density in a main magnetic pole and a position in the pole;
Figs. 5, 6 and 10 are respectively diagrams each schematically showing examples of a magnetic transducer head according to the present invention;
Figs. 7, 8 and 9 are graphs to explain the present invention; and Figs. 11 through 17 are schematic illustrations showing manufacturing steps of the magnetic transducer head of the present invention.
DESCRIPTION OF THE PREFERRED RMBODIMENTS
The inventors clarified that in the magnetic -trans-ducer head having such auxiliary core, a magnitude of magnetic field for the recording a-t the -top portion of the main magnetic pole depended upon a magnitude of the exci-ting magnetic field at -the top of the main maynetic pole, in other words, a magnitude of a magne-tic field at the top of the main magnetic pole when the main magnetic pole was removed but instead, the auxiliary core around which the coil is wound exists alone.
Therefore, to record the signal on the magnetic recording medium most efficiently, it should be arranged to 7 7 i generate the strongest magnetic field at the top of the main magnetic pole, when a predetermined current is applied to the exciting coil. Generally, as the diameter of the coil wound becomes large, the attenuation of the magnetic field at the position remote from the coil on the central axis of the coil becomes small. On the other hand, the magnetic field on the central axis of the coil becomes smaller when the winding diameter of the coil becomes larger.
Accordingly, it is necessary to consider the arrangement of the coil, the position of the coil wound on -the core, the diameter of the coil and so on properly, to maximize the exciting magnetic field.
On the basis of the above-mentioned consideration and clarification and further with various experiments and discussious, the inventors propose a magnetic transducer head for use in vertical magnetization mode recording with high recording efficiency.
Now, embodiments of the magnetic transducer head according to the present invention will be described with reference to Fig. 5 and the following drawings in which like references corresponding to those of Figs. 1,2 and 4 designate the same elements and parts.
In the figures, reference letter H denotes an overall arrangement of a magnetic transducer head according to the present invention.
In the embodiment of the present invention, as shown in Fig. 5 or 6 by way of example, there is provided the main magnetic pole 2 formed of a thin film of magnetic material made of, for example, permalloy, Sendust alloy and so on of about 0.5 to 3 ~m thick, a thickness of which is ~ 7 797~ ~
represented by letter t in the figure. On both surfaces or one surface of the main magnetic pole 2 is magnetically bonded tight an auxiliary core or cores 10 formed of high permeability material such as Mn- Zn ferrite, Ni- Zn ferrite or the like. This auxiliary core 10 is placed in such a manner that the top thereof may be located at the position farther back from the top of the main magnetic pole 2 facing the slidiny surface of the magnetic recording medium (not shown) along which the main magnetic pole 2 slides by a distance Q.
The coil 4 is placed on this auxiliary magnetic core 10 in such a manner as to wrap both the auxiliary magnetic core 10 and the main magnetic pole 2 sandwiched therebetween. ~ore precisely, the coil 4 is placed on the auxiliary magnetic core 10 as near as possible to the end of the auxiliary core, so that the top surface thereof may be coincident with the top surface of the auxiliary magnetic core 10, which is then wound therearound by, for example, a winding of a conductive wire.
Now, let us take a thickness of the auxiliary core as _, that is, a distance from one surface of the main magnetic pole to which a surface of the auxiliary magnetic pole abut to the inner surface of the coil, and a winding thickness of the coil 4 as b. In this invention the above defined dimensions, Q, a and _ are selected to satisfy a relation that (a + b2 )/Q is not more than 2.4 but not less than 0.55 under the practical dimension of Q ranging from 10 to 200 ~Im. The reason why the distance Q is selected as described above is based upGn the results shown in Figs. 7 and 8 in which the magnetic field in the axial direction 1 1~97~:~
component at the top of the main magnetic pole 2 is examined when the value of (a + 2 )/Q is changed in the magnetic transducer head, a construction o~ which is shown in Figs.
5 and 6. In Figs. 7 and 8, the magnetic field is expressed as a relative value when the maximum value thereof is taken as 100% . In Fig. 7, curves 11, 12 and 13 each describe the case where the positions of the tops of the paired auxi-liary magnetic cores 10, which are located symmetrically to grip the main magnetic pole 2 therebetween as shown in Fig. 5, are selected such that the distance Q between the tops of the main magnetic pole 2 and the auxiliary magnetic core 10 may change as 30 ~m, 50 ~m and 100 ~m, respectively. Also, curves 14, 15 and 16 of E`ig. 8 describe the case in which the position of the top of the auxiliary magnetic core 10 located at one side of the main magnetic pole 2 as shown in Fig. 6 is selected such that the distance Q between the tops of the main magnetic pole 2 and the auxiliary core 10 may change as 30 ~m, 50 ~m and 100 ~m, respectively. In this case, Fig. 8 shows a distribution of the magnetic field in which the spacing _ where no auxiliary magnetic core is provided is selected equal to the distance a.
Turning back to Fig. 7, it is understood that the magnetic field becomes strongest when (a + b2 )/Q is 1.3, the magnetic field decreases by about ~2 % (+1 %)of the maximum value when (a+ b2 )/Q,is in a range from 0.8 to 2.0 and it decreases by -4 ~ (~2 %) of -the maximum value when (a + b )/Q
is in a range from 0.65 to 2.4. Also, with reference to Fig.
8, the magnetic field becomes strongest when (a+ b2 )/Q is 1.22, it decreases by about - 2 % (+1 %) of the maximum value when (a + 2 )/Q is in a range from 0.7 to 2.0 and it decreases 7~
by -4 ~ ( ~ 2%) of the maximum value when ta ~ b2 )/~ is in a range from 0.55 to 2.42. Comparing the representations in Fig. 7 with those of Fig. 8, an tendency of how the top of the main magnetic pole 2 influences the magnetic field is nearly equal in both cases where the auxiliary magnetic core 10 is provided at both surfaces of the main magnetic pole 2 and where it is provided on the one surface thereof as shown in Figs. 5 and 6. From Figs. 7 and 8, it is understood that the magnetic field at the top of the main 1~ magnet~c pole 2 is effectively enhanced if (a+ b2 )/~ is in the range from 0.55 to 2.4, which is why the range of (a+ b2 )/Q is selected to be from 0.55 to 2.4.
In the case, as shown in Fig. 6, when the auxiliary core 10 is placed at one side surface of the main magnetic 15 . pole 2, the similar magnetic field at the top of the main magnetic pole 2 is measured while the distance d from the other side surface of the main magnetic pole 2, which the auxiliary core 10 is not attached to, to the inner surface of the coil 4 opposing thereto is selectively changed with the results shown in Fig. 9. In this case, Q is selected as 50 ~m, a is selected as 50 ~m and _ is selected as 20 ~m. In addition, the length c of the coil 4 is selected as 50 ~m.
As it will be clear from Fig. 9, the magnetic field at the top of the main magnetic pole 2 becomes larger if d > b is established. Thus, when the auxiliary magnetic core 10 is placed on one side of the main magnetic pole 2, it is desired to select the relationship between the lengths d and _ so as to satisfy d ~ b.
The depth oi ~he coil 4, namely, the size represented 3ti by the letter c in Figs. 5 and ~ does not influence the recordin~
7 ~ 1 efficiency so much. But, if the depth c is too much large as compared with the thickness _, this is not preferable because it causes the recording efficiency to be lowered.
Therefore, the value of c/b must be selected to be 5 or below, particularly, for example, less than about 2 to 3.
While in the auxiliary core 10, the distance a is selected at its top side where the coil 4 is wound such that (a + b2 )/Q becomes in a range from 0.55 to 2.4, the thickness at its rear end side later than the por-tion around which the coil 4 is wound can be increased in consideration of its mechanical s-trength.
Fig. 10 illustrates an example of such case in which each of reinforcing members 17 formed of non magnetic material such as Zn ferrite is further bonded to the top of the auxi-liary magnetic core 10 so as to extend to and grip the top of the main magnetic pole 2 to thereby enable the top of the main magnetic pole 2 to be reinforced.
IE the auxiliary core 10 is formed on one side of the main magnetic pole 2, the reinforcing member 17 provided on the side where the auxiliary magnetic core 10 is not provided is extended backward or downward so as -to uni-te it with the main magnetic pole 2, whereby the coil 4 can be wound around both this reinforcing member 17 extended and the auxi-liary magnetic core 10 on the other side of the main magnetic pole 2.
sy way of example, the sizes of the respective parts of the magnetic transducer head H whose structure is shown in Fig. 10 are enumerated below. _ is 100 ~Im, a is 150 ~m, b is_ 50 ~m and _ is 1.5 mm. In addition, the thickness of the rear par-t of the auxiliary magnetic core 10, the thickness of ~ ~7977~
which is large and shown by e in Fig. 10 can be selected as 1 mm and the length thereof, which is designated by f, can be selected as 4 mm.
In this case, the magnetic recording medium 1 whose layer of high permeability material 6 is formed of permalloy layer of 0.5 ~m thick and whose magnetic recording layer 7 is formed of Co - Cr alloy layer of 0.5 ~m thick may be utiliæed.
An example of a method for producing a magnetic transducer head according to the present invention will next be described in detail with reference to Fig. 11 and the following drawings.
First, as shown in Fig. 11, a joint body 30 is prepared by bonding a rectangular shape block of magnetic material 20 and a plate shape block of non-magnetic material 270 The block of magnetic material 20 may be formed of Mn - Zn ferrite or Ni - Zn ferrite, and the block of non-magnetic material may be formed of glass, ceramics, non-magnetic Zn ferrite and so on. However, it is desired that both of the magnetic and the non-magnetic materials have similar thermal expansion coefficient with each other, thus it is preferred that the magnetic and non-magnetic blocks 20, 27 are formed of magnetic and non-magne-tic ferrite, respectively. The magnetic material block 20 and the non-magnetic material block 27 can be bonded together through the use of melt bonding of glass, water glass, organic adhesive, such as epoxy resin, or inorganic adhesive.
Next, the joint body 30 made of the magnetic material block 20 and the non-magnetic material block 27 is cut out along surfaces shown by two-dots chain lines ml, m2, ~ ~L7!~'7~
m3, in Fig. 11 to provide a plurali-ty of plate members 31, each having a predetermined thickness as illustrated in Fig. 12.
In Fig. 12, a major surface 31a which stretches over the magnetic material memher 20 and -the non magne-tic member 27 composing the plate member 31 is polished to have a mirror finish. An insulating layer 32 made of such as SiO2, Si3N4, AQ2O3 or the like is formed on this major surface 31a on which a thin film magne-tic material layer 22 made of, for example, permalloy, Sendust alloy and so on of 0.5 to 3 ~m thick is formed by vacuum evapolation, sputtering or the lik~.
Next, as illustrated in Fig. 13, the thin film magnetic material 22 is selectively removed by using a photolithography technique to leave band-shaped portions 22', 22", , which are placed in parallel to each other with a predetermined width and spacing. The portions between the band shape thin film 22, 22" are filled in with non -magnetic material 34 to form a flush surface with the surface of thin film bands of magnetic material. In addition, materials such as SiO2, Si3N4 and AQ2O3 or -the like may be formed thereon.
On the other hand, as shown in Fig. 14, other plate member 31', which is cut away Erom the same joint body 30 as described previously in Fig. 11 whic}l is formed of the maynetic material member 20 and the non-magnetic member 27, is prepared. A major surface 31a' thereof is likewise polished to make a mirror finish and as shown in Fig. 14, this major surface 31a' is bonded to the surface side of the plate member 31 on which the thin film maynetic material 22 and the ~ ~79~1 non-magnetic layer 34 are formed as shown in Fig. 13. In this case, a recess or notch 35 is formed in advance on the major surface 31a' of the plate member 31' by, for example, etching and an adhesive 36 is filled or charged into this S notch 35, both the plate members 31 and 31' can be bonded with one another strongly.
If necessary, as illustrated in Fig. 15, the external surfaces of both the plate members 31 and 31' are cut away at the side of the non magnetic member 27, the respective thicknesses of which are selected to be smaller than those of the remaining parts. As shown by two-dots chain lines nl, n2, , in Fig. 15, the bonded plates 31 and 31' are cut away to include the respective band-shaped thin film of magnetic materials 22', 22", , the top surfaces each are ground or polished so as to construct a sliding surface S with the magnetic recording medium (not shown) as illustrated in Fig. 16.
Thus, the magnetic transducer head H according to the present invention can be manufactured in which the thin film main magnetic pole 2 made of thin film magnetic material 22 is provided to abut the sliding surface S for the magnetic recording medium, the reinforcing members 17 formed of the non magnetic member 27 are placed on both sides of the main magnetic pole 2 at the vicil~ity of the top thereof and the auxiliary cores 10 formed of the magnetic recording member 20 are placed behind the reinforcing member 17.
In this case, when the non-ma~netic material 3~ arc located adjacent to -the main magnetic pole 2, a spacing or gap between both of the reinforcing members 17 on both sides of the main magne-tic pole 2 abutting against the sliding ~ ~7~
surface s ~or the magnetic recording medium is almost filled by the non-magnetic material 34 so that an amount of adhesive which will be filled into the aforesaicd gap is made less, in other words, the area abutting the sliding surface S for the magnetic recording medium in which the adhesive is used is reduced to be less than that of the case where the non-magnetic material 34 is not provided. Thus, an occurrence of head clogging caused by the fact that much adhesive abuts against the sliding surface S can be reduced.
This magnetic transducer head lI is wound by -the coil 4 around its thin portion in the position at which it is moved farther back than the sliding surface S. In this case, even in the magnetic transducer head H thus constructed, a relationship for dimension and arrangement between the re-spective parts thereof is selected as described previously.
Also, this magnetic transducer head H is attached to, as, for example, shown in Fig. 17, a head holder 43 through which each of apertures 41 is bored to attach the same on a rotary drum of a VTR (video tape recorder) and on which each of conductive terminal patterns 42 is bonded. Each terminal end of the coil 4 a-t the magnetic transducer head H is con-nected electrically to each conductive terminal pattern 42 through soldering, by way of example.
~s described above, according -to the magnetic transducer head of the present invention, although the coil 4 is placed farther bac~ than the sliding surface S for the magnetic recording medium, the recording efficiency is high.
~lso, it is obvious that the same effect can be achieved if the magnetic transducer head according to the present invention is also applied for a magnetic transducer ~ 1797~
head of a multi-elements type in which a plurality oE main magnetic poles 2 are placed.
The above description is given on the preferred embodiments of the invention, but it will be apparent that many modifications and variations could be effected by one skilled in the art without departing from the spirits or scope of the novel concepts of the invention, so that the scope of the invention should be determined by the appended claims only.
Claims (8)
1. A magnetic transducer head comprising:
a main magnetic pole formed of a thin film magnetic material having a major surface and facing to a magnetic recording medium at one end thereof;
an auxiliary magnetic core provided adjacent to said major surface of said thin film magnetic material decreases abruptly having a thickness a along a direction perpendicular to said major surface;
an end of said auxiliary magnetic core being remote from said end of said main magnetic pole with a distance ?;
a coil wound around said main magnetic pole and said auxiliary magnetic core; and at said end of said auxiliary magnetic coil, said core having a thickness b, wherein said a, b and ? are selected for satisfying that a value (a + ?)/? not less than 0.55 but not more than 2.4.
a main magnetic pole formed of a thin film magnetic material having a major surface and facing to a magnetic recording medium at one end thereof;
an auxiliary magnetic core provided adjacent to said major surface of said thin film magnetic material decreases abruptly having a thickness a along a direction perpendicular to said major surface;
an end of said auxiliary magnetic core being remote from said end of said main magnetic pole with a distance ?;
a coil wound around said main magnetic pole and said auxiliary magnetic core; and at said end of said auxiliary magnetic coil, said core having a thickness b, wherein said a, b and ? are selected for satisfying that a value (a + ?)/? not less than 0.55 but not more than 2.4.
2. A magnetic transducer head comprising:
a main magnetic pole formed of a thin film magnetic material having a major surface, said main magnetic pole confronting a magnetic recording medium path at one end of said main magnetic pole;
an auxiliary magnetic core provided adjacent to said major surface of said thin film magnetic material at both sides thereof, each of said auxiliary magnetic core having a thickness a along a direction perpendicular to said major surface;
an end of each said auxiliary magnetic core closest to the magnetic recording medium path being spaced from said one end of said main magnetic pole by a distance ?;
a coil wound around said main magnetic pole and said auxiliary magnetic cores; and at said end of each said auxiliary magnetic core, said coil having a thickness b, wherein the dimensions a,b, and ? are selected such that the value of (a + ?)/? is not less than 0.65 but not more than 2.4.
a main magnetic pole formed of a thin film magnetic material having a major surface, said main magnetic pole confronting a magnetic recording medium path at one end of said main magnetic pole;
an auxiliary magnetic core provided adjacent to said major surface of said thin film magnetic material at both sides thereof, each of said auxiliary magnetic core having a thickness a along a direction perpendicular to said major surface;
an end of each said auxiliary magnetic core closest to the magnetic recording medium path being spaced from said one end of said main magnetic pole by a distance ?;
a coil wound around said main magnetic pole and said auxiliary magnetic cores; and at said end of each said auxiliary magnetic core, said coil having a thickness b, wherein the dimensions a,b, and ? are selected such that the value of (a + ?)/? is not less than 0.65 but not more than 2.4.
3. A magnetic transducer head according to claim 1, wherein said main magnetic pole is provided with said auxiliary magnetic core at one side thereof and the other side thereof is formed with a non-magnetic spacing, a distance of which is more than said b.
4. A magnetic transducer head according to claim 1, wherein said main magnetic pole is provided with a non-magnetic material at both sides thereof in a surface facing to said magnetic recording medium.
5. A magnetic transducer head according to claim 1, wherein said auxiliary magnetic core is formed such that a portion remote from the surface facing to said magnetic recording medium and around which a coil is not wound has a thickness more than that of other portion around which the coil is wound.
6. A magnetic transducer head according to claim 2, wherein said main magnetic pole is provided with a non-magnetic material at both sides thereof at said one end of said main magnetic pole confronting said magnetic recording medium path.
7. A magnetic transducer head according to claim 2, wherein each auxiliary magnetic core at a portion thereof remote from said one end of said main magnetic pole and on the side of said coil more remote from said one end of said main magnetic pole has a thickness more than the thickness of the portion of said auxiliary magnetic core around which the coil is wound.
8. A magnetic transducer head according to claim 2, wherein said value (a + ?)/? is not less than 0.8, but not more than 2Ø
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4674681A JPS57162114A (en) | 1981-03-30 | 1981-03-30 | Magnetic head |
| JP46746/81 | 1981-03-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1179771A true CA1179771A (en) | 1984-12-18 |
Family
ID=12755893
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000399018A Expired CA1179771A (en) | 1981-03-30 | 1982-03-22 | Perpendicular mode magnetic transducer head |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS57162114A (en) |
| CA (1) | CA1179771A (en) |
| DE (1) | DE3211581A1 (en) |
| FR (1) | FR2502824B1 (en) |
| GB (1) | GB2095888B (en) |
| NL (1) | NL8201231A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59157819A (en) * | 1983-02-25 | 1984-09-07 | Sony Corp | Vertical magnetic recording head |
| WO1984003788A1 (en) * | 1983-03-22 | 1984-09-27 | Sony Corp | Single magnetic pole type of composite magnetic head for perpendicular recording |
| JPH07101483B2 (en) * | 1983-08-29 | 1995-11-01 | ソニー株式会社 | Thin film magnetic head |
| US4672494A (en) * | 1983-09-01 | 1987-06-09 | Matsushita Electric Industrial Co., Ltd. | Magnetic head for effecting perpendicular magnetic recording |
| JPS60197914A (en) * | 1984-03-20 | 1985-10-07 | Olympus Optical Co Ltd | Vertical magnetization type magnetic head |
| JPS6134710A (en) * | 1984-07-26 | 1986-02-19 | Akai Electric Co Ltd | Magnetic head |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5810764B2 (en) * | 1977-09-30 | 1983-02-28 | 岩崎 俊一 | magnetic recording and reproducing device |
| JPS5584015U (en) * | 1978-12-07 | 1980-06-10 | ||
| JPS56165918A (en) * | 1980-05-23 | 1981-12-19 | Ricoh Co Ltd | Vertical magnetic recorder and reproducer |
-
1981
- 1981-03-30 JP JP4674681A patent/JPS57162114A/en active Granted
-
1982
- 1982-03-22 CA CA000399018A patent/CA1179771A/en not_active Expired
- 1982-03-24 NL NL8201231A patent/NL8201231A/en not_active Application Discontinuation
- 1982-03-29 GB GB8209188A patent/GB2095888B/en not_active Expired
- 1982-03-29 DE DE19823211581 patent/DE3211581A1/en not_active Ceased
- 1982-03-29 FR FR8205338A patent/FR2502824B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3211581A1 (en) | 1982-12-02 |
| FR2502824B1 (en) | 1985-01-04 |
| JPH0157405B2 (en) | 1989-12-05 |
| GB2095888A (en) | 1982-10-06 |
| NL8201231A (en) | 1982-10-18 |
| GB2095888B (en) | 1984-09-26 |
| FR2502824A1 (en) | 1982-10-01 |
| JPS57162114A (en) | 1982-10-05 |
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