Patent Publication Number: US-2006007607-A1

Title: Magnetically sensitive element having its control element integrated therewith

Description:
TECHNICAL FIELD  
      The present invention relates to a magnetically sensitive element such as a magnetic element in which a giant Barkhausen Jump phenomenon appears.  
     BACKGROUND ART  
      Magnetically sensitive elements such as magnetic elements in which giant Barkhausen Jump phenomena appear are used along with associated control devices for controlling the operation of the magnetically sensitive elements, and the magnetic element-and-control combinations are used in a variety of machines and apparatuses. In addition to the particular magnetic element in which a giant Barkhausen Jump phenomenon appears such magnetically sensitive elements include Hall devices; MR elements (magneto-resistive elements); GMR elements (giant magneto-resistance elements); TMR elements (tunneling magneto-resistive elements) and so on. Particularly magnetic elements in which a giant Barkhausen Jump phenomenon appears have been widely used in pulse generators, measuring devices, detectors markers and such like these days.  
      When applied to these apparatuses, a magnetically sensitive element and an associated control unit are separately made and adjusted, and then these products are joined together, fixedly arranged on a substrate or base plate, and finally adjusted.  
      One of such prior art magnetically sensitive devices is disclosed in Laid-Open Patent Application No. 2000-30939.  
      Disadvantageously the conventional method of making such magnetically sensitive elements involves arranging, connecting and fixing the separate elements onto a substrate. A variety of parts and tools such as brackets, jigs and soldering and bonding tools need to be used, and still disadvantageously the required precise adjustment for absolute/relative positioning of parts is a very difficult, laborious work. Accordingly the manufacturing cost is high, and the quality of these products varies widely. Still disadvantageously, improvement in precision and stability, and reduction in size are restricted to certain limits.  
      The object of the present invention is to provide a magnetically sensitive element with an operation controlling element integrated therewith and with or without a pickup coil or coils integrated therewith, thus guaranteed to be free of the defects as described above.  
     DISCLOSURE OF THE INVENTION  
      According to one aspect of the present invention there is provided a magnetically sensitive element characterized in that it is integrated with an operation controlling element.  
      According to one embodiment of the present invention the magnetically sensitive element and the operation controlling element are integrally connected according to the film-forming process.  
      According to another embodiment of the present invention the magnetically sensitive element and the operation controlling element are integrally connected by sticking pieces of films or thin layers on each other.  
      According to still another embodiment of the present invention the operation controlling element is given in the form of a single layer.  
      According to still another embodiment of the present invention the operation controlling element is given in the form of plural layers.  
      According to still another embodiment of the present invention the operation controlling element comprises a permanent magnet.  
      According to still another embodiment of the present invention the operation controlling element comprises an electromagnet.  
      According to still another embodiment of the present invention the operation controlling element includes a magnetic circuit forming member.  
      According to still another embodiment of the present invention the magnetically sensitive element is a magnetic element in which a giant Barkhausen Jump phenomenon appears.  
      According to still another embodiment of the present invention the magnetically sensitive element is integrated with a pickup coil or coils.  
      Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       FIG. 1  is a perspective view of a magnetically sensitive element with an associated operation controlling element integrated therewith according to the first embodiment of the present invention;  
       FIG. 2  is a perspective view of a magnetically sensitive element with an associated operation controlling element integrated therewith according to the second embodiment of the present invention;  
       FIG. 3  is a perspective view of a magnetically sensitive element with an associated operation controlling element integrated therewith according to the third embodiment of the present invention;  
       FIG. 4  is a perspective view of a magnetically sensitive element with an associated operation controlling element integrated therewith according to the fourth embodiment of the present invention;  
       FIG. 5  is a perspective view of a magnetically sensitive element with an associated operation controlling element integrated therewith according to the fifth embodiment of the present invention;  
       FIG. 6  is a perspective view of a magnetically sensitive element with an associated operation controlling element integrated therewith according to the sixth embodiment of the present invention;  
       FIG. 7  is a perspective view of a magnetically sensitive element with an associated operation controlling element and pickup coils integrated therewith according to the seventh embodiment of the present invention;  
       FIG. 8  is a plane view of the seventh embodiment of the present invention;  
       FIG. 9  is a perspective view of a magnetically sensitive element with an associated operation controlling element integrated therewith according to the eighth embodiment of the present invention; and  
       FIG. 10  is a perspective view of a magnetically sensitive element with an associated operation controlling element integrated therewith according to the ninth embodiment of the present invention. 
    
    
     PREFERRED EMBODIMENTS OF THE PRESENT INVENTION  
       FIG. 1  shows a magnetically sensitive element with an associated operation controlling element integrated therewith according to the first embodiment of the present invention. It comprises a substrate  10  having the operation controlling element  11  and the magnetically sensitive element  12  both integrally formed thereon. The substrate  10  is of a material permitting thin film layers to be formed thereon, not only a solid material such as silicon or glass but also a flexible material and even a liquid. The substrate  10  may be a variety of laminated structures such as a flip chip bonding. The magnetically sensitive element  12  may be a giant Barkhausen element, a Hall element, an MR element, a GMR element or a TMR element. The operation controlling element  11  generally means an object which can apply a magnetic field to the magnetically sensitive element  12 , such as a permanent magnet or an electromagnet, and may include an associated magnetic circuit which is positioned so close to the magnetically sensitive element  12  that it may lead the magnetic flux from the magnet toward the magnetically sensitive element  12 . The operation controlling element  11  is an element to create a magnetic field having an influence over the magnetically sensitive element  12 .  
      In the first embodiment the operation controlling element  11  and the magnetically sensitive element  12  are so integrally connected according to the thin-film forming process that the operation controlling element  11  is laid on the substrate  10 , and that the magnetically sensitive element  12  is laid on the operation controlling element  11 .  
      When occasions demand, there may be an intervening insulation or non-magnetic layer between the substrate  10  and the overlying operation controlling element  11  or between the operation controlling element  11  and the overlying magnetically sensitive element  12 , although such intervening layers are not shown in  FIG. 1 . These intervening layers can be formed during thin-film forming process.  
      In this particular embodiment the magnetically sensitive element  12  is a magnetic element in which a giant Barkhausen Jump phenomenon appears, and the operation controlling element  11  is a permanent magnet. Such magnetically sensitive elements  12  are of an iron-and-nickel alloy, an iron-and-cobalt alloy or an amorphous material, and its structure is a multi-lamination of hard and soft layers or a single layer. When the magnetic element is alternately exposed to the magnetic field of one or the other polarity, the magnetic walls inside are made to shift quickly, causing the reversal of magnetization. Then, an impulsive voltage appears across a nearby pickup coil. The reversal of magnetization is independent from the varying rate of the external magnetic field, but is responsive to the rise of the external magnetic field above a certain critical strength. The reversal of magnetization due to the quick shift of magnetic walls is called the “giant Barkhausen Jump phenomenon”.  
      Such magnetically sensitive elements and operation controlling elements can be provided according to the following film forming processes: 
          1) sputtering process;     2) vacuum vaporizing process;     3) plating process and     4) CVD process.        

      As disclosed in Patent Application Laid-Open No. 2000-30939 working conditions can be so changed at each step of the film-forming process that the so formed magnetic layers may be different from each other in crystal structure. Specifically the crystal size, directivity, coarseness and other factors may be changed to control the coercive field strength and anisotropy of each magnetic layer in which a giant Barkhausen Jump phenomenon appears.  
      As for the permanent magnet used as the operation controlling element a film of CoPt may be used other than the ordinary permanent magnet material.  
      The method of integrally forming the magnetically sensitive element and operation controlling element on the substrate other than those described above may comprise the steps of bonding a magnetically sensitive element and an operation controlling element on each other on the substrate.  
       FIG. 2  schematically shows a magnetically sensitive element with an associated operation controlling element integrated therewith according to the second embodiment of the present invention. It comprises a substrate  20  having the operation controlling element  21  and the magnetically sensitive element  22  both built thereon.  
      In this particular embodiment the opposite sub-elements of the operation controlling element  21  and the magnetically sensitive element  22  are series-arranged in a straight longitudinal line on the substrate  20 . These operation controlling element and magnetically sensitive element  21  and  22  are integrally formed according to the thin film-forming process.  
      The film-forming process is similar to the one described above in connection with the first embodiment.  
       FIG. 3  schematically shows a magnetically sensitive element with an associated operation controlling element integrated therewith according to the third embodiment of the present invention. It comprises a substrate  30  having the operation controlling element  31  and the magnetically sensitive element  32  both built thereon.  
      In this particular embodiment the opposite sub-elements of the operation controlling element  31  and the magnetically sensitive element  32  are parallel-arranged on the substrate  30  with the magnetically sensitive element  32  arranged between the opposite sub-elements. These operation controlling element and magnetically sensitive element  31  and  32  are integrated with each other according to the thin film-forming process.  
      The film-forming process is similar to the one described above in connection with the first embodiment.  
       FIG. 4  schematically shows a magnetically sensitive element with an associated operation controlling element integrated therewith according to the fourth embodiment of the present invention. The operation controlling element which is integrated with the magnetically sensitive element in the first, second or third embodiment is of a single-layered structure. In contrast, in the fourth embodiment the operation controlling element is of a multi-layered structure. Specifically, a magnetically sensitive element  42  is formed on one surface of the substrate  40 , and a layer of first operation controlling element  41  is formed on the underlying magnetically sensitive element  42 , and a layer of second operation controlling element  43  is formed on the other surface of the substrate  40 . These layers  41 ,  42  and  43  are formed as a whole according to the thin film-forming process.  
      The film-forming process is similar to the one described above in connection with the first embodiment.  
       FIG. 5  schematically shows a magnetically sensitive element with an associated operation controlling element integrated therewith according to the fifth embodiment of the present invention. Similar to the fourth embodiment, a multi-layered operation controlling element is formed relative to the magnetically sensitive element  52 . Specifically two layers of first operation controlling element  51  are formed in line with the magnetically sensitive element  52  on one surface of the substrate  50 , and a layer of second operation controlling element  53  is formed on the other surface of the substrate  50 . These layers  51 ,  52  and  53  are formed as a whole according to the thin film-forming process.  
      The film-forming process is similar to the one described above in connection with the first embodiment.  
       FIG. 6  schematically shows a magnetically sensitive element with an associated operation controlling element integrated therewith according to the sixth embodiment of the present invention. Similar to the fourth embodiment, a multi-layered operation controlling element is formed relative to the magnetically sensitive element. Specifically two opposite layers of first operation controlling element  61  are formed parallel with the magnetically sensitive element  62  on one surface of the substrate  60  with the magnetically sensitive element  62  between the opposite layers of operation controlling element  61 , and a layer of second operation controlling element  63  is formed on the other surface of the substrate  60 . These layers  61 ,  62  and  63  are formed as a whole according to the thin film-forming process.  
      The film-forming process is similar to the one described above in connection with the first embodiment.  
      As regards the first, second and third embodiments the operation controlling element of one polarity is provided for alternate application of magnetic field to the magnetically sensitive element. As regards the fourth, fifth and sixth embodiments the operation controlling element of the opposite polarities are provided for alternate application of magnetic field. The multi-layered operation controlling element may have two layers formed on the front or rear surface of the substrate, not one layer formed on each surface as in the fourth, fifth and sixth embodiments.  
       FIG. 7  schematically shows a magnetically sensitive element with an associated operation controlling element integrated therewith according to the seventh embodiment of the present invention.  FIG. 8  is a plane view of the seventh embodiment. Similar to the fourth embodiment, a multi-layered operation controlling element is integrally formed relative to the magnetically sensitive element, and pickup coils are integrally formed, also. Specifically as shown in  FIGS. 7 and 8 , two first sub-elements  71  of the operation controlling element and the magnetically sensitive element  72  are aligned in a straight line on one surface of the substrate  70 , and the two pickup coils  74  and an overlying second sub-element  73  of the operation controlling element are formed on the other surface of the substrate  70 . These layers  71 ,  72 ,  73  and  74  are formed as a whole according to the thin film-forming process.  
      The film-forming process is similar to the one described above in connection with the first embodiment.  
       FIG. 9  schematically shows a magnetically sensitive element with an associated operation controlling element integrated therewith according to the eighth embodiment of the present invention. As shown, an operation controlling element  81  in the form of permanent magnet and a magnetically sensitive element  82  are parallel-arranged and formed on the substrate  80 , and magnetic circuit forming members  85  are so formed that the magnetic flux from the permanent magnet  81  may be led to the magnetically sensitive element  82 , thereby allowing the permanent magnet  82  to apply its magnetic field effectively to the magnetically sensitive element  82 . The magnetic circuit forming members  85  are included in the operation controlling element  81  as constitutional parts. These elements  81 ,  82  and  85  are formed as a whole according to the thin film-forming process.  
      The film-forming process is similar to the one described above in connection with the first embodiment.  
       FIG. 10  schematically shows a magnetically sensitive element with an associated operation controlling element integrated therewith according to the ninth embodiment of the present invention. As shown, the opposing sub-elements  91  of the operation controlling element in the form of permanent magnet and the magnetically sensitive element  92  are series-arranged and formed on the substrate  90 , and a magnetic circuit forming member  96  is formed to allow the sub-elements  91  of the permanent magnet to apply its magnetic field effectively to the magnetically sensitive element  92 . The magnetic circuit forming member  96  is included in the operation controlling element as its constitutional part. These elements  91 ,  92  and  96  are formed as a whole according to the thin film-forming process.  
      The film-forming process is similar to the one described above in connection with the first embodiment.  
      In the above described embodiments the magnetically sensitive element is a magnetic element in which a giant Barkhausen Jump phenomenon appears. It should be noted that the present invention is not limited to use of such magnetic element; same effects can be caused by using a Hall element, an MR element (magneto-resistive element), a GMR element (giant magneto resistance element) or a TMR element (tunneling magnetoresistive element). Also, in the above described embodiments a permanent magnet is used as an operation controlling element, but an electromagnet can be used instead.  
     INDUSTRIAL UTILITY  
      Integration of a magnetically sensitive element and an associated operation controlling element into a single chip provides advantages as follows: such integrated magnetic sensitive devices can be easily handled; the degree of freedom is increased in designing a machine or apparatus having a magnetic sensitive device built therein; reduction both in size and manufacturing cost is attained thanks to reduction of parts in number; the production line can be less complex, significantly benefiting the mass production.  
      The magnetic field can be confined in the single chip, and the magnetically sensitive element is insensitive to external magnetic field if any, and still advantageously the products can have same qualities or characteristics.  
      Particularly magnetic elements in which a giant Barkhausen Jump phenomenon appears and an associated operation controlling element can be strictly adjusted to assure the equilibrium in magnetic strength.