GB2268310A - Magnetic Head & Manufacturing Method Thereof - Google Patents
Magnetic Head & Manufacturing Method Thereof Download PDFInfo
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- GB2268310A GB2268310A GB9312388A GB9312388A GB2268310A GB 2268310 A GB2268310 A GB 2268310A GB 9312388 A GB9312388 A GB 9312388A GB 9312388 A GB9312388 A GB 9312388A GB 2268310 A GB2268310 A GB 2268310A
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- magnetic
- thin film
- ferromagnetic
- magnetic head
- ferrite
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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
- G11B5/187—Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features
- G11B5/1875—"Composite" pole pieces, i.e. poles composed in some parts of magnetic particles and in some other parts of magnetic metal layers
- G11B5/1877—"Composite" pole pieces, i.e. poles composed in some parts of magnetic particles and in some other parts of magnetic metal layers including at least one magnetic thin film
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- Manufacturing & Machinery (AREA)
- Magnetic Heads (AREA)
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Abstract
The invention provides a magnetic head having an operative surface and comprising two core elements 100, 102. The core elements 100, 102 each have a projecting portion 116 which extends along the operative surface towards the said portion of the other core, each projecting portion having a face surface. The face surfaces face each other and are separated from each other with the magnetic gap of the head therebetween. In one aspect of the invention the projecting portions 116 are each configured such that the sides 110a thereof which extend from the operative surface and which extend away from the face surface are substantially parallel to each other. In a second aspect of the invention, at least one of the face surfaces is provided with a ferromagnetic film 114c and a plurality of non-ferromagnetic films 114a, 114b. The arrangement is such as to provide a non- ferromagnetic oxide film 114a directly on the said face, a non-ferromagnetic metal film 114b on the said oxide film 114a and the ferromagnetic film 114c on the said metal film 114b. <IMAGE>
Description
MAGNETIC HEAD & MANUFACTURING METHOD THEREOF
The present invention relates to a magnetic head suitable for being used for a video tape recorder (VTR) and a manufacturing method thereof. More particularly, this invention is directed to a magnetic head and its manufacturing method which can provide a track width with high precision with respect to size by making a section of the track vertical and that can prevent the magnetic ferrite blocks of the head from being cracked.
As a recording density of the magnetic tape which is used as a recording media of the video tape recorder has been increased, a use of the magnetic tape having high residual magnetic flux density (Br) and high coercive force (Hc), ie., a metal magnetic tape forming a magnetic recording layer by coating a non-ferromagnetic material with metal powder by means of a bonding agent. In case where the magnetic head is used for a metal tape and a digital audio tape, the intensity of magnetic field of a magnetic gap of the head shall be increased due to the high coercive force of these tapes, and therefore a magnetic erase head for erasing signals recorded in the tapes shall have much higher saturated magnetic flux density.Thus, this invention is directed to the magnetic head in which a ferromagnetic thin film which has a high saturated magnetic flux density by
means of sputterings on the face forming the magnetic gap of the magnetic ferrite blocks
of metal oxides is deposited. A summarised explanation thereof is stated below.
Figure 1 is a perspective view illustrating a conventional magnetic head.
Referring to figure 1, the magnetic gap 14 is formed between the joining faces of a pair
of magnetic core elements 10 and 12 and a coil winding groove 16 is formed in one
magnetic core element 12, wherein a coil 18 is wounded. The magnetic head is used for
the digital audio tape recorder, the digital video tape recorder or the 8mm video tape
recorder, and the pair of magnetic core elements 10 and 12 comprise of ferromagnetic material like Mn-Zn single crystal ferrite and for example, the SiO2 non-ferromagnetic thin film exists in the magnetic gap 14.
However, such a conventional magnetic head uses a bonding glass when joining a pair of magnetic core elements 10 and 12. Upon joining them, it occurs the phenomenon that SiO2 is eroded by the bonding glass and gets to be in one with the bonding glass.
That is, the conventional magnetic head results in the problem that because SiO2 which shall not be melted at the temperature of joining actually becomes one with the bonding glass and melts, the length of the magnetic gap 14 changes so that the magnetic characteristics are degraded.
To solve the above-mentioned problem, Japanese Laid-Open Patent Publication
No. Sho 62-295204 indicates the magnetic head which was manufactured to cause no degradation of the magnetic characteristics by preventing the magnetic gap from being eroded.
Figure 2A is a perspective view illustrating the previous magnetic head to prevent the magnetic gap from being eroded. This magnetic head includes a pair of magnetic core elements 20 and 22 of ferromagnetic material like ferrites. In the magnetic core element 20, a coil winding groove 24 and a reinforcing groove 26 are formed. The coil winding groove 24 is wounded with coil 28. In the joining faces of a pair of magnetic core elements 20 and 22, a track width regulating groove 29 is formed. In the groove 29 and the reinforcing groove 26, a glass for a join 30 having a determined melting point is changed, thereby a pair of magnetic core elements 20 and 22 can be joined with each other by the glass for a join 30.
In the joining faces including the track width regulating groove 29 of the magnetic core element 22, a deposited film containing SiO2 is formed. As illustrated in figure 2B, the deposited film 31 comprises of the Cr first non-ferromagnetic metal thin film 31a (approximately 200A), the Sendust (an alloy of Fe-Al-Si) ferromagnetic thin film 31b (approximately 2.6cm), the SiO2 first non-ferromagnetic thin film 31c (approximately 1.8cm), the Cr second non-ferromagnetic metal thin film 31d (approximately 1.2-1.3ym) and the SiO2 second non-ferromagnetic thin film 31e (approximately 200-500A), which are sequential from the surface of the magnetic core element 22.
Herein, the first non-ferromagnetic metal thin film 31a is used for improving the intensity of the joining of the magnetic ferrite core elements 22 and the Sendust 31b.
The SiO2 first non-ferromagnetic thin film 31c and the Cr second non-ferromagnetic metal thin film are used for forming the magnetic gap.
In order to form the magnetic gap as described above, the SiO2 first nonferromagnetic thin film 31c is coated with the Cr second non-ferromagnetic metal thin film 31d, and the Cr first non-ferromagnetic metal thin film 31a and the Sendust 31b and the SiO2 second non-ferromagnetic thin film are deposited at the front and back of the deposited films, respectively, thereby upon joining, enabling to reduce the reaction of the
SiO2 of first non-ferromagnetic thin film 31c forming the magnetic gap and bonding glass 30 so that the length of the magnetic gap is less changeable and therefore the degradation of the magnetic characteristics is prevented.
Figure 3A illustrates the magnetic head which is similar with the magnetic head shown in figure 2A. The magnetic head shown in figure 3A has a similar performance with the magnetic head illustrated in figure 2A except for the track width regulating groove 49 formed in an inclined shape rather than a semi-circular shape. Since the reference numerals in figures 3A and 3B which are similar with those in figures 2A and 2B have similar constitutions, the functions according to those constructions are also similar with. A detailed description thereof is omitted for a brevity of the present specification.
Figures 5A to SF illustrate the separate processes of manufacturing the magnetic head shown in figure 2A. After a moulding process has been made to a joint of the.face contacting the magnetic core block 22a, a pair of magnetic core blocks 20a and 22a formed in a determined regular square by cutting the ferromagnetic material like ferrites make the track width regulating groove 29 in a determined interval in accordance with the direction of the length of the magnetic core blocks 20a, 22a, at one of them at least as illustrated in figure SA. Then, in the magnetic core block 20a, each of the coil winding groove 24 and the reinforcing groove 26 is formed to be continued with its length direction.
As shown in figure 5B, on the magnetic core block 22a, the deposited films illustrated in figure 2B, ie., the first non-ferromagnetic metal thin film 31a, the Sendust 31b, the first non-ferromagnetic thin film 31c, the second non-ferromagnetic metal thin film 31d, and the second non-ferromagnetic thin film 31e are formed in a suitable method like sputtering. Also, the SiO2-PbO 30a is put up on the track width regulating groove 29, the coil winding groove 24 and the reinforcing groove 26 of the magnetic core block 20a.
The conventional magnetic head is manufactured by heating and melting SiO2 30a which has been put up, charging SiO2 in the track width regulating groove 29 and the coil winding groove 24 and the reinforcing groove 26 as shown in figure SC, grinding
SiO2 in the coil winding groove so that a low second part of the coil winding groove 24 as shown in figure SD, and removing SiO2 30a which comes out of the track width regulating groove 29 by polishing.
After sputtering SiO2 30a in the joined face of the magnetic core block 20a, the magnetic core blocks 20a and 20b are joined with the glass having a low melting point 30 by making the magnetic core blocks 20a and 20b faced each other and secondly heating them at the melting temperature of SiO2 30a, as shown in figure SE.
The magnetic core blocks 20a and 20b which have been finished their join are cut after the cutting line C as shown in figure SE. At the same time, the unnecessary portions in a low part of the reinforcing groove 26 is cut after the cutting line D.
Thereby, at least one or more semi-manufactured magnetic head can be obtained as shown in figure SF. Then, the semi-manufactured magnetic head is followed by the magnetic head having the constitution as shown in figure 2A by means of the procedures that the joined face of semi-manufactured magnetic head and the magnetic recording media is moulded in a shape of a circular arc and that the coil winding groove 24 is wound with a coil.
However, the conventional magnetic heads as illustrated in figures 2A and 3A have the following defects.
Figures 4A and 4B illustrate the shapes of the track width regulating grooves 29 and 49 of the conventional magnetic heads having the constitutions shown in figures 2A and 3A, respectively. In the magnetic head having the track width regulating groove 29 as in figure 4A, as already explained referring to figures SA through SE, a glass rod for a join is placed on the magnetic core block 20a including the track width regulating groove 29 and is melted. Following the melting step, in order to remove the melted glass, a grinding process like lapping is done, in which a track width Tw of the uppermost of the magnetic core block 20a formed upon the lapping may be increased.
Namely, supposing that the track width Tw prior to the lapping is Ll, if the lapping operation is wrongly performed, since the actual track width becomes , a finally formed track width shall increase. In figure 4B, as the same as described above, the track width may increase. Therefore, since the track width Tw after the lapping of the magnetic core block 20a or 40a becomes bigger than that formed at the magnetic core block 22a or 40a, this is a cause of a bad product and furthermore makes an efficiency of production lower.
Meanwhile, although the Cr non-ferromagnetic metal thin film 31a is used in order to improve the intensity of bonding the magnetic ferrite core element 20 and the alloy of Fe-Al-Si (Sendust) 31b, since coefficients of the thermal expansion of the
Sendust ferromagnetic metal thin film 31b and the non-ferromagnetic metal thin film 31a are different from each other, (ie. since a coefficient of thermal expansion of Cr is about 70 x 10-6/9C, and that of Sendust is about 140-150 x 10-7, the coefficient of Cr is much bigger than that of Sendust), it is observed that a fine crack in the magnetic core element happens as in figure 6.Such a crack is not initially a matter with respect to the degradation of the magnetic characteristics, however, as time goes by, the crack becomes bigger gradually, and the ferromagnetic metal film has a small profits, thereby causing the problem that the magnetic ferrite core element breaks. Furthermore, since the crack occurred in the ferrite core element affects the density of the magnetic flux, there is the problem that the erasing efficiency of the magnetic head is rapidly reduced.
Since the conventional magnetic head manufactured by the process as in figures
SA through 5E includes the complicated procedures of forming the track, the coil winding groove and the reinforcing groove, forming the deposited film by the sputtering, moulding the bonding glass, grinding the glass, lapping, joining the magnetic core blocks and bonding the glass, it had the problem that the remarkable time and expense were required for manufacturing it.
Furthermore, since the prior art in this field should perform the processes of grinding the bonding glass and lapping required for the super-preciseness, if any error happens in these processes, the track width of the mutual joined magnetic core blocks is different, and therefore, the rate of a badness of the magnetic head had increased.
In addition, the bonding glass should have a hardness to the extent that two magnetic ferrite elements are firmly joined together and spread and it should not generate any blowhole. However, the bonding glass used for the conventional magnetic head generates blowholes by a reaction to the deposited films. These blowholes are confined among the glass and become holes. In this regard, since such holes appear on the face connecting with the recording media, the conventional magnetic head had the problem that a scratching phenomenon of the recording media has been occurred.
Various objects and examples of the invention will now be described, without limiting the scope of the invention.
It is a general object of the present invention to solve the above-indicated problems and to provide a new and improved magnetic head by forming a track of the magnetic head in a vertical shape, thereby reducing a rate of a badness in the magnetic head and improving an efficiency of production.
Another object of the present invention is to provide a magnetic head to make its erasing efficiency maximum by preventing a crack from being occurred by forming the inner films of magnetic ferrite core elements with non-ferromagnetic oxides and nonferromagnetic metal thin film.
Another object of the present invention is to provide a manufacturing method of a magnetic head having its track in a vertical shape and having an improved construction of the bonding glass which has an excellent spread and does not generate blowholes, wherein a process of manufacturing the magnetic head is simple since the process requiring for a super-conciseness like lapping is not necessary and time and expense for manufacturing it are reduced thereby increasing the efficiency of production.
A magnetic head according to the present invention to achieve the above-stated objects is characterised in that a pair of magnetic core elements have the projecting ferrite portions respectively, wherein a section shape is projected in the connecting face with the magnetic recording media; a high ferromagnetic material having higher saturated magnetic flux density than ferrites comprising the magnetic core elements is coated in one of the projecting ferrite portions of the magnetic core elements; a front end of the projecting ferrite portion forms the magnetic gap; magnetic core elements are mutually joined by a bonding glass with a determined construction; the projecting ferrite portions of the magnetic core elements is formed vertically to a face forming the gap; inner films comprising of a first non-ferromagnetic thin film and a first nonferromagnetic metal thin film are deposited in the vertical projecting ferrite portions; a ferromagnetic metal thin film having a high saturated magnetic flux density is deposited on the inner films; a second non-ferromagnetic thin film and a second non-ferromagnetic metal thin film are deposited on the ferromagnetic metal thin film.
In a magnetic head according to the present invention, the magnetic core elements use Mn-Zn ferrite, Ni-Zn ferrite, a crystallised glass, ceramic which are magnetic materials having a high tracing rate.
It is preferable to use a non-crystallised magnetic alloy, Fe-Al-Si alloy (Sendust),
Ni-Fe alloy which are formed by a technique for forming a thin film like deposition or sputtering, or nitride having a high saturated magnetic flux density as the ferromagnetic metal thin film materials for the magnetic head according to the present invention.
Non-ferromagnetic thin film can be formed by either any one of SiO2, Awl203 and TOs or a mixture of two or more.
However, it is preferable to form non-ferromagnetic metal thin film by anyone of
Cr, Ti, Al.
A magnetic head according to the present invention comprises of deposited films, wherein the inner film of the first non-ferromagnetic thin film and the first nonferromagnetic metal thin film efficiently prevents an occurrence of a crack, and since it is preferable that the inner film has a thickness to the extent that a degradation of the magnetic characteristics is not caused, the preferable thickness of the inner film is 0.01 0.03cm.
Additionally, a manufacturing method of a magnetic head according to the present invention in order to achieve another object of the present invention is characterised by a step of forming a plural of track width regulating grooves at the face where a gap of a pair of magnetic ferrite blocks is formed and forming the vertically shaped injecting ferrite portions between the adjacent track width regulating grooves; a step of forming a coil winding groove vertically crossing with the track width regulating groove at the face where the gap of anyone of the above blocks has been formed to make the magnetic ferrite blocks be in one; a step for depositing sequentially a first nonferromagnetic thin film of non-ferromagnetic oxides, a first non-ferromagnetic metal thin film of non-ferromagnetic metal materials, a ferromagnetic metal thin film of materials with high saturated magnetic flux density, a second non-ferromagnetic thin film made of the material of same characteristics with the first non-ferromagnetic thin film, and a second non-ferromagnetic metal thin film made of the material of same characteristics with the first non-ferromagnetic metal thin film on any one magnetic ferrite block where the track width regulating groove and the vertically shaped projecting ferrite portion are formed; a step of obtaining a magnetic head of a pair of magnetic core elements by cutting two magnetic ferrite blocks in accordance with a determined position after using a bonding glass at the face where the gap of a pair of magnetic core blocks has been formed; and a step of grinding the connecting face of a magnetic recording media of the magnetic head in a shape of a circular arc.
With respect to a manufacturing method of a magnetic head according to the present invention, the glass used for connecting the magnetic ferrite blocks comprises of
SiO2 of 15-40 weight percent, PbO of 45-75 weight percent, ZnO of 0-15 percent, K2O of 0-3 weight percent, NO of 0-6 weight percent, A1203 of 0-3 weight percent, By203 of 5-20 weight percent and B205 of 1-2 weight percent, wherein it is preferable to have an excellent spread over the joined face and to prevent blowholes from being occurred.
Further description of the invention will now be given, again by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a perspective view illustrating a conventional magnetic head;
Figure 2A is a perspective view illustrating another conventional head;
Figure 2B is a plan view enlarging a connecting face of the magnetic recording media of the magnetic head shown in figure 2A;
Figure 3A is a perspective view illustrating further conventional magnetic head;
Figure 3B is a plane view enlarging a connecting face of the magnetic recording media of the magnetic head shown in figure 3A;
Figures 4A and 4B are the separate plane views enlarging the magnetic ferrite blocks manufactured according to the prior arts shown in figures 2A and 3A;;
Figures SA through SF are the separate perspective views showing a manufacturing method of the conventional magnetic head shown in figure 2a:
Figure 6 is an outline corresponding to the picture observing by a scanning electron microscope (SEt) a crack of a first non-ferromagnetic metal thin film with chrome according to the prior art which was formed by sputterings on the magnetic ferrite blocks;
Figure 7A is a perspective view illustrating a magnetic head according to the present invention;
Figure 7B is a plane view enlarging a connecting face of the magnetic recording media of the magnetic head according to the present invention illustrated in figure 7A;
Figure 7C is a plane view illustrating a magnetic ferrite block manufactured according to the present invention shown in figure 7A;;
Figures 8A through 8F are the separate perspective views showing a manufacturing method of the magnetic head according to the present invention;
Figure 9 illustrates an outline corresponding to the picture observing by a scanning electronic microscope a first non-ferromagnetic metal thin film formed by the sputterings on the magnetic ferrite blocks according to the present invention.
Embodiments of a magnetic head according to the present invention and its manufacture method are explained in detail below referring to the attached drawings.
Figure 7A is a perspective view illustrating a magnetic head according to the present invention. A coil winding groove 104 and a reinforcing groove 106 are formed at one of a pair of magnetic core elements 100, 102 of ferromagnetic materials, ie. at magnetic core element 102. Coil 108 is wound in the coil winding groove 104. Since the magnetic core elements 100, 102 use the magnetic materials like ferrites, it is possible to use Ni-Zn ferrites which are the magnetic material with high tracing rate, or non-ferromagnetic materials like crystallised glass or ceramic.
A track width regulating groove 110 is formed at the facing sides of a pair of magnetic core elements 100, 102. A bonding glass is charged at the coil winding groove 110 and the reinforcing groove 106. The bonding glass 112 shall firmly join magnetic core elements 100, 102.
At a projecting ferrite portion 116 of the magnetic core element 100, a deposited film 114 containing SiO2 is formed, wherein as shown in an enlarged view of figure 7B, is sequentially deposited from the surface of the projecting ferrite portion 116 of the magnetic core element 110 by a first non-ferromagnetic thin film 114a of nonferromagnetic material, a first non-ferromagnetic metal thin film 114b of nonferromagnetic metal material, a ferromagnetic metal thin film 1 14c of ferromagnetic material, a second non-ferromagnetic thin film 114d made of the material of same characteristics with the first non-ferromagnetic thin film 114a, and a second nonferromagnetic metal thin film 114e made of the material of same characteristics with the first non-ferromagnetic thin film 114b.
From figure 7B, the first non-ferromagnetic thin film 114a can comprise anyone of SiO2, A1203 or To205, and the second non-ferromagnetic metal thin film 114b can comprise anyone of Cr, Ti or Al.
The ferromagnetic metal thin film 1 14c can comprise non-crystallised magnetic alloy formed by the thin film forming technique like a physical deposition or sputtering, an alloy of Fe-Al-Si (Sendust), an alloy of Ni-Fe, or nitride being ferromagnetic material having a high saturated magnetic flux density.
Since it is preferable that the second non-ferromagnetic thin film 114d comprises the same material with the first non-ferromagnetic thin film 114a, it can be formed by anyone of SiO2, A1203 or Ta205. Also, it can be formed by anyone of Cr, Ti or Al which is the same with the second non-ferromagnetic metal thin film 114b.
The preferable deposited film 114 has thicknesses of the first non-ferromagnetic thin film 114a being more than 0.005yam, the first non-ferromagnetic metal thin film 114b being more than 0.005cm, the ferromagnetic metal thin film 114c being from 2.0 3.0cm, the second non-ferromagnetic thin film 114d being 2.0m and the second nonferromagnetic metal thin film 114e being 1.2clam. As shown in figure 7B, since the first non-ferromagnetic thin film 114a and the first non-ferromagnetic metal thin film 114b form the inner film of the magnetic head according to the present invention, a desired thickness of the inner film is of the range from 0.01-0.03ttm. Also, the second nonferromagnetic thin film 114b and the second non-ferromagnetic metal thin film 114e form the magnetic gap. Herein, the reason why the thickness of the inner film is restricted as 0.01-0.03tcm is because a function of preventing any crack cannot be sufficiently operated if the thickness is lower than 0.01m and a degradation of the magnetic characteristics is caused if it is more than 0.03cm.
As illustrated in detail in the enlarged view of figure 7C, the regulating groove 110 includes a portion 110a which is vertically extended to the side forming the gap of magnetic core element 100 or 102 and a portion 110b which is inclined in a determined angle against the vertically extended portion 110a. The reason that the track width regulating groove 110 forms the vertical extending portion 110a and the inclined portion 100b is to prevent the track width Tw from being changed upon the final joining of two magnetic core elements 100, 102 as mentioned above, and in general, to minimise the time required for a manufacture and to reduce the rate of a badness of the product.
Although figure 7C illustrates the inclined portion 110b continued to the vertical extending portion 100a, a magnetic head according to the present invention is not limited thereto and if the vertical portion 110a necessarily exists, it does not matter that the inclined portion is in any shape. That is, if the vertical extending portion 110a exists, the inclined portion 110b may be in a shape of rounding. Eventually, the magnetic head according to the present invention does not have a degradation of the magnetic characteristics since its track width Tw is always the same with respect to the lengths before and after the process, by forming the vertical extending portion 110a with a determined length from the face where the gap of the magnetic core elements 100, 102 is formed.
Furthermore, since the non-ferromagnetic metal thin film (Cr-layer) is directly deposited at the back of the magnetic core element and it is processed by heating, the magnetic head according to the present invention is different from the conventional magnetic head in which the crack occurred in the magnetic core element. That is, in the present magnetic head, no crack occurs in the magnetic core elements by forming non ferromagnetic thin film (ie. SiO2-layer) on the magnetic core elements 100, 102.
(Referring to figure 9.)
Figures 8A and 8F are the perspective views showing a process of manufacturing the magnetic head according to the present invention. Reference numbers 100a and 102a set forth in figure 8A indicate for the magnetic ferrite blocks cut in a determined regular square by cutting the ferromagnetic material like ferrites.
The surface of the magnetic ferrite blocks 100a, 102a is smoothly moulded. The track width regulating groove 110 is formed in a determined interval to the length direction of the magnetic ferrite blocks 100a, 102a as illustrated in figure 8B so that a vertical projecting ferrite portion 120 by a vertical extending portion 110a is formed between the adjacent track width regulating groove 110.
In figure 8B, the track width regulating groove 110 is formed to be continued to the length direction of the magnetic ferrite blocks 100a, 102a, however, the track width regulating groove 110 can be formed only in a part of the magnetic ferrite block 102a.
Meanwhile, the coil winding groove 104 and the reinforcing groove 106 crossing with the track width regulating groove 110 are formed on the side where the gap of the magnetic ferrite block 102a is formed. In this regard, in a case where the track width regulating groove 110 is formed to be continued to the length direction of magnetic ferrite blocks 100a, 102a, the reinforcing groove 106 is not needed. However, in a case where the track width regulating groove 110 is formed only in a part of the magnetic ferrite block 100a, 102a, the reinforcing groove is needed. In addition, both the coil winding groove 104 and the reinforcing groove 106 are formed in the magnetic ferrite blocks 100a, 102a.
In the status that the track width regulating groove 110 and the coil winding groove 104 or the reinforcing groove 106 have been formed, the deposited film 114 is formed only on the magnetic ferrite block 100a by using the techniques for forming a thin film like the sputtering, the physical deposition, or the chemical plating. Regarding the present invention, a preferable technique for forming a thin film is the sputtering.
On the magnetic ferrite block 100a as shown in figure 8C, the first nonferromagnetic thin film 114a is first formed by the sputtering of non-ferromagnetic oxides like SiO2, A1203 or TO5 in a thickness of about 0.005cm. Following the formation of the first non-ferromagnetic thin film 114a, the first non-ferromagnetic metal thin film 114b can be formed by the sputtering of non-ferromagnetic metals like Cr, Ti or Al in a thickness of about 0.005cm onto the first non-ferromagnetic thin film 114a.
The first non-ferromagnetic thin film 114a and the first non-ferromagnetic metal thin film 114b form the important inner film in the present invention. In this regard, since non-ferromagnetic oxides like SiO2, Awl203 or TO5 exist between the magnetic ferrite block 100a and the first non-ferromagnetic metal thin film 114, the present invention does not occur any cracking phenomenon of the magnetic ferrite block 100a by means of the first non-ferromagnetic metal thin film (Cr, Ti, Al).
On the inner film of the present invention, ferromagnetic metal of high saturated magnetic flux density like Sendust, non-crystallised magnetic alloy, Ni-Fe alloy, or nitride is sputtered in a thickness of about 2-3,um, thereby forming the ferromagnetic metal thin film 114c.
On the ferromagnetic metal thin film 114, the second non-ferromagnetic oxides and the second non-ferromagnetic metal are in turns sputtered to form the magnetic gap, wherein it is preferable that the second non-ferromagnetic oxides are the same with the first non-ferromagnetic oxides, ie. SiO2, Awl203 or Ta2Os. The second non-ferromagnetic oxides are sputtered in a thickness of about 2,um, thereby forming the second nonferromagnetic thin film 114b.
On the second non-ferromagnetic thin film 114b, the first non-ferromagnetic metal, ie. Al, Fi or Cr is sputtered in a thickness of about 1.2cm, thereby forming the second non-ferromagnetic metal thin film 114e.
The formation of the magnetic ferrite blocks 100a, 102a into a vertical shape can maintain the same track width, and furthermore, the deposition of the first nonferromagnetic thin film 114a between the magnetic ferrite block 100a and the first non ferromagnetic metal thin film 114a prevents the cracking phenomenon of magnetic ferrite block 100a that may be caused by the chrome.
After the deposited film 114 has been deposited on the magnetic ferrite block
100a, to join a pair of the magnetic ferrite blocks 100a, 102a coupled as shown in figure
8D, the bonding glass 112 in a rod shape is inserted in the coil winding groove 104 and
the reinforcing groove 106, followed by heating at a steady temperature within the range
of S00-8000C and then cooling.
The results of measuring the spread and hardness by changing the construction of
the bonding glass 112 used for joining are set forth at Cable 1) on the following page. TABLE 1
PbO ZnO K2O SiO2 Na2O Al2O3 Bi2O3 B2O5 FEATURES TEMP. SPREAD FOAM HARDNESS 40-50 10-15 3-5 30-40 - - - - HIGH X FINE 400 50-55 5-10 3-5 30-40 3-6 - - - HIGH " " 430 45-55 3-10 3-5 30-40 3-6 - - - HIGH " " 400 60-70 - - 15-25 3-6 - - - MEDIUM O BAD 320 80-90 - - 8-12 - 2-3 - - LOW " " 330 50-55 0-4 - 15-25 0-6 2-3 10-16 - MEDIUM " " 400 55-60 - 0-2 15-25 0-5 0-2 10-20 - MEDIUM " " 400 60-70 0-4 1-3 20-30 3-6 0-2 - - MEDIUM X " 400 50-75 0.5-3 0.5-1.5 15-25 2-5 1-3 5-15 1-2 MEDIUM O FINE 410 Features of the bonding glass according to the temperature for heating As disclosed in the foregoing Table 1, when the glass comprise SiO2 of 15-25 weight percent, ZnO of 0.5-3.0 weight percent, K2O of 0.5-1.5 weight percent, NO of 2.0-5.0 weight percent, A1203 of 1.0-3.0 weight percent, Bi2O3 of 5.0-15.0 weight percent, and B205 of 1.0-2.0 weight percent, a spread of the glass is most excellent and any blowholes are not generated. Furthermore, since a hardness is big, it is possible to directly join the magnetic ferrite blocks 100a, 102a.That is, since it is not necessary to perform the processes as illustrated in figure 2A and figures SA through SF, if only the bonding glass 112 is inserted between the magnetic ferrite blocks 100a, 102a, it is directly fast thereto, thereby enabling the manufacturing process to be simple.
Following the joining process, if the magnetic ferrite blocks 100a, 102a is cut after the cutting line C of figure 8F, the magnetic head as shown in figure 8F. The magnetic head as illustrated in figure 7A can be obtained by processing the face connecting with the magnetic recording media of the magnetic head obtained as in figure 8F and winding the coil 108 thereon.
As indicated above, the magnetic head according to the present invention reduces the rate of a badness of the product by vertically forming the track shape of the magnetic head, thereby improving the efficiency of production. The present magnetic head prevents a crack from being occurred by forming the inner film of the deposited film of non-ferromagnetic oxides and non-ferromagnetic metal thin films, thereby maximising the erasing efficiency of the magnetic head. Furthermore, since in the present magnetic head, its track is performed in a vertical formation, the spread of the bonding glass is excellent and no blowholes are generated, any process required for super-preciseness, ie.
like lapping and moulding/grinding is not necessary. That is, since the present invention simplifies the manufacture process, it has effects of reducing the time and expense for manufacturing.
Although the present invention is explained referring to the attached drawings, the present invention is not limited as to the drawings only. Some changes and amendments can be made to the present invention within the scope of the claims. For example, since the track width regulating groove 110 can be formed only on a portion adjacent to the face connecting with the magnetic recording media instead of being extended to the whole length direction of magnetic ferrite blocks 100a, 102a, in this case the reinforcing groove 106 should be formed. Otherwise, in a case where the track width regulating groove 110 is extended to the whole length direction of the magnetic ferrite blocks 100a, 102a, the reinforcing groove 106 may not be needed.
Claims (21)
1. A magnetic head having an operative surface and comprising two core elements each having a projecting portion, the projecting portions extending along the operative surface towards each other and each having a respective face surface, the face surfaces facing each other and being separated from each other with the magnetic gap of the head therebetween, wherein the projecting portions each being configured such that the sides thereof which extend from the operative surface and which extend away from the face surface are substantially parallel to each other.
2. A magnetic head having an operative surface and comprising two core elements each having a projecting portion, the projecting portions extending along the operative surface towards each other and each having a respective face surface, the face surfaces facing each other and being separated from each other with the magnetic gap of the head therebetween, at least one of the face surfaces being provided with a ferromagnetic film and a plurality of non-ferromagnetic films, wherein a non-ferromagnetic oxide film is provided directly on the said face, a non-ferromagnetic metal film is provided thereon and the ferromagnetic film is provided on the said metal film.
3. A magnetic head, which includes first and second magnetic core elements, characterised in that:
each of the magnetic core elements includes magnetic ferrite blocks with projecting ferrite portions, wherein a section formation is projected on the face connecting with a magnetic recording media;
a projecting ferrite portion of any one of said magnetic ferrite core elements is coated with high ferromagnetic material having higher saturated magnetic flux density than said ferrite;
a front end of said projecting ferrite portion has a magnetic gap and said magnetic core elements are connected with each other by means of a bonding glass;
said projecting ferrite portions of said magnetic ferrite blocks are vertically extended to the face forming the gap; and
said vertical projecting ferrite portions are deposited sequentially by a first nonferromagnetic thin film made of non-ferromagnetic oxides, for preventing crack phenomenon of said magnetic ferrite core elements, a first non-ferromagnetic metal thin film made of non-ferromagnetic metal material, a ferromagnetic metal thin film of material having a high saturated magnetic flux density, a second non-ferromagnetic thin film made of the material of the same characteristics with the first non-ferromagnetic thin film so as to form a magnetic gap, and a second non-ferromagnetic metal thin film made of the material of the same characteristics with the first non-ferromagnetic metal thin film.
4. The magnetic head according to claim 3, characterised in that said nonferromagnetic thin film comprise any one of SiO2, Al2O3, or To205.
5. The magnetic head according to claim 3, characterised in that said nonferromagnetic metal thin films comprise any one of Cr, Ti or Al.
6. The magnetic head according to claim 3, characterised in that a thickness of said thin film including said first non-ferromagnetic thin film and said first non-ferromagnetic metal thin film is 0.01 to 0.3cm.
7. The magnetic head according to claim 3, characterised in that said first nonferromagnetic thin film has a thin thickness to the extent that a crack of the magnetic core element caused by said first non-ferromagnetic metal thin film can be prevented.
8. The magnetic head according to claim 3, characterised in that said bonding glass has the suitable spread of hardness for joining said magnetic core elements together and comprises the construction in which no blowholes are occurred.
9. The magnetic head according to claim 8, characterised in that the bonding glass comprises SiO2, of 15-40 weight percent, PbO of 45-75 weight percent, ZnO of 0-15 weight percent, K2O of 0-3 weight percent, NO of 0-6 weight percent, Also, of 0-3 weight percent, and 3205 of 5-20 weight percent.
10. A manufacturing method of a magnetic head to erase signals recorded in a magnetic recording media, this method comprising the steps of:
forming a plural of track width regulating grooves at the face where the gap of a pair of magnetic ferrite blocks with a high tracing rate is formed, thereby a vertically projecting ferrite portion is formed between the adjacent track width regulating grooves;
forming a coil winding groove which crosses with the track width regulating groove at the face where the gap of any one of the blocks is formed, in order to make the magnetic ferrite blocks be in one;;
sequentially depositing the first non-ferromagnetic thin film made of nonferromagnetic oxides, for preventing a crack phenomenon of the magnetic core elements, a first non-ferromagnetic metal thin film made of non-ferromagnetic metal material, a ferromagnetic metal thin film of material having a high saturated magnetic flux density, a second non-ferromagnetic thin film made of the material of the same characteristics with the first non-ferromagnetic thin film so as to form a magnetic gap, and a second nonferromagnetic metal thin film of the material of the same characteristics with the first nonferromagnetic metal thin film, onto any one of magnetic ferrite blocks in which the track width regulating groove and the surface of the vertically projecting ferrite portion are formed;;
joining the two magnetic ferrite blocks at the face where the gap of a pair of magnetic ferrite blocks is formed by using the bonding glass;
obtaining a magnetic head comprising a pair of magnetic core elements by cutting the joined block as a determined position; and
moulding/grinding the side connecting with the magnetic recording media of the magnetic head in shape of a circular arc.
11. The manufacturing method of the magnetic head according to claim 10, characterised in that said first non-ferromagnetic thin film is deposited on the magnetic ferrite block by any one of SiO2, Awl203, or To205.
12. The manufacturing method of the magnetic head according to claim 10, characterised in that said first non-ferromagnetic metal this film is deposited on said first non-ferromagnetic thin film by any one of Cr, Ti or Al.
13. The manufacturing method of the magnetic head according to claim 10, characterised in that a thickness of said thin film including said first non-ferromagnetic thin film and said first non-ferromagnetic metal thin film is from 0.01 - 0.3clam.
14. The manufacturing method of the magnetic head according to claim 13, characterised in that the first non-ferromagnetic thin film is deposited in a thickness being more than 0.00511m at least.
15. The manufacturing method of the magnetic head according to claim 13, characterised in that the first non-magnetic metal thin film is deposited in a thickness being more than 0.005m at least.
16. The manufacturing method of the magnetic head according to claim 10, characterised in that a track width regulated by the crack width regulating groove which has been formed at the magnetic ferrite blocks is always kept as being the same.
17. The manufacturing method of the magnetic head according to claim 10, characterised in that the bonding glass has the suitable spread and hardness for joining the magnetic ferrite blocks together and comprises SiO2 of 1540 weight percent, PbO of 45-75 weight percent,
ZnO of 0-15 weight percent, K20 of 0-3 weight percent, NO of 0-6 weight percent, Awl203 of 0-3 weight percent, Bi2O3 of 5-20 weight percent, and B205 of 1-2 weight percent.
18. A method of manufacturing a magnetic head of the type claimed in claim 1, comprising the step of forming the said sides substantially parallel to each other.
19. A method of manufacturing a magnetic head of the type claimed in claim 2, comprising the steps of providing the said oxide film directly on the said face surface, providing the said metal film on the said oxide film and providing the said ferromagnetic film on the said metal film.
20. A magnetic head substantially as hereinbefore described with reference to and as illustrated in figures 7 to 9 of the accompanying drawings.
21. A method of manufacturing a magnetic head substantially as hereinbefore described with reference to and as illustrated in figures 7 to 9 of the accompanying drawings.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019920010405A KR940011674B1 (en) | 1992-06-16 | 1992-06-16 | Magnetic head |
| KR1019920010406A KR940011675B1 (en) | 1992-06-16 | 1992-06-16 | Manufacturing method for magnetic head |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9312388D0 GB9312388D0 (en) | 1993-07-28 |
| GB2268310A true GB2268310A (en) | 1994-01-05 |
| GB2268310B GB2268310B (en) | 1996-10-30 |
Family
ID=26629116
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9312388A Expired - Fee Related GB2268310B (en) | 1992-06-16 | 1993-06-16 | Magnetic head & manufacturing method thereof |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH06203323A (en) |
| GB (1) | GB2268310B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002072493A1 (en) * | 2001-03-08 | 2002-09-19 | Matsushita Electric Industrial Co., Ltd. | Magnetic head-use sealing glass, magnetic head and magnetic recording/reproducing device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0195235A2 (en) * | 1985-03-15 | 1986-09-24 | Hitachi, Ltd. | Magnetic head and method of producing the same |
| GB2202078A (en) * | 1987-02-04 | 1988-09-14 | Sony Corp | Magnetic heads |
| US4816949A (en) * | 1986-09-12 | 1989-03-28 | Hitachi, Ltd. | Magnetic head containing amorphous alloy and crystallizable glass |
| EP0459403A2 (en) * | 1990-05-31 | 1991-12-04 | Sony Corporation | Method for manufacturing a magnetic transducer head |
| EP0466159A2 (en) * | 1990-07-13 | 1992-01-15 | Fuji Photo Film Co., Ltd. | Composite magnetic head |
| US5164870A (en) * | 1988-10-13 | 1992-11-17 | Canon Denshi Kabushiki Kaisha | Magnetic head employing a magnetic gap material composed of Cr2 O3 |
| US5222006A (en) * | 1989-06-16 | 1993-06-22 | Canon Denshi Kabushiki Kaisha | Magnetic head and core chip having a magnetic thin film |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3634305A1 (en) * | 1985-10-09 | 1987-04-16 | Canon Kk | MAGNETIC HEAD |
| JPH0770018B2 (en) * | 1985-12-20 | 1995-07-31 | 株式会社日立製作所 | Magnetic erase head |
| US5007158A (en) * | 1988-02-09 | 1991-04-16 | Sanyo Electric Co., Ltd. | Method of manufacturing magnetic heads |
| JPH01260615A (en) * | 1988-04-12 | 1989-10-17 | Nec Kansai Ltd | Magnetic head |
| JPH0278004A (en) * | 1988-09-13 | 1990-03-19 | Nec Kansai Ltd | Magnetic head and production thereof |
| JPH0312338A (en) * | 1989-06-09 | 1991-01-21 | Tdk Corp | Deposited glass for magnetic head and magnetic head |
-
1993
- 1993-06-16 JP JP14522393A patent/JPH06203323A/en active Pending
- 1993-06-16 GB GB9312388A patent/GB2268310B/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0195235A2 (en) * | 1985-03-15 | 1986-09-24 | Hitachi, Ltd. | Magnetic head and method of producing the same |
| US4816949A (en) * | 1986-09-12 | 1989-03-28 | Hitachi, Ltd. | Magnetic head containing amorphous alloy and crystallizable glass |
| GB2202078A (en) * | 1987-02-04 | 1988-09-14 | Sony Corp | Magnetic heads |
| US5164870A (en) * | 1988-10-13 | 1992-11-17 | Canon Denshi Kabushiki Kaisha | Magnetic head employing a magnetic gap material composed of Cr2 O3 |
| US5222006A (en) * | 1989-06-16 | 1993-06-22 | Canon Denshi Kabushiki Kaisha | Magnetic head and core chip having a magnetic thin film |
| EP0459403A2 (en) * | 1990-05-31 | 1991-12-04 | Sony Corporation | Method for manufacturing a magnetic transducer head |
| EP0466159A2 (en) * | 1990-07-13 | 1992-01-15 | Fuji Photo Film Co., Ltd. | Composite magnetic head |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002072493A1 (en) * | 2001-03-08 | 2002-09-19 | Matsushita Electric Industrial Co., Ltd. | Magnetic head-use sealing glass, magnetic head and magnetic recording/reproducing device |
| US7012783B2 (en) | 2001-03-08 | 2006-03-14 | Matsushita Electric Industrial Co., Ltd. | Sealing glass for magnetic head, magnetic head, and magnetic recording/reproducing device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2268310B (en) | 1996-10-30 |
| GB9312388D0 (en) | 1993-07-28 |
| JPH06203323A (en) | 1994-07-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20010616 |