Magnetic marker and manufacturing method therefor

A compact and superior magnetic marker for an electronics apparatus for surveillance of article comprises at one or more wire members and a plane member contacting substantially directly to each other. An angle of the magnetic easy axis of the plane member relative to the longitudinal direction of the wire member is between 40.degree. and 90.degree. to show large Barkhausen reversal. An influence of demagnetizing field can be reduced by using the simple structure. The magnetic marker can be produced continuously at a low cost.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an electronic article surveillance system 
or identification system wherein a magnetic marker is attached to a good 
and the good is surveilled or identified according to a signal generated 
by the magnetic marker, or in particular, to the magnetic marker and a 
manufacturing method therefor. 
2. Description of the Prior Art 
Recently, an electronic article surveillance or identification system are 
used widely in order to prevent theft of goods, to deal goods or the like. 
In such an apparatus, a special marker is attached to a good as an object, 
and the good is surveilled or identified by detecting a signal generated 
by the marker. A variety of detection signals has been developed, and an 
appropriate marker is selected according to a use. The apparatuses are 
distinguished mainly as follows: Those using a magnetization process of a 
special soft magnetic material, those using a steep impedance change at a 
fixed frequency of an LC resonance circuit, and those radiating special 
electromagnetic waves. 
Among them, apparatuses using magnetic markers are used widely because 
markers, can be produced at a low cost. A steep magnetization change of a 
magnetic material is detected with a voltage induced in a detection coil. 
Oscillation due to magnetostriction, high permeability, square hysteresis 
of magnetization or the like is used for detection. 
For example, Japanese Patent Publication 27958/1991 describes a system 
using a marker made of an amorphous metallic thin wire, and the marker 
uses square hysteresis of a magnetostrictive material. In the system, an 
alternating magnetic field as an enquiry signal is generated in a 
surveillance area, and a voltage induced in a detection coil according to 
magnetization of the metallic thin wire is recognized as a detection 
signal. In such a system, it is needed to distinguish the magnetic marker 
from a general magnetic material such as an iron plate of a shopping bag 
or the like by using a specified waveform of induced voltage. The 
magnetization along the longitudinal direction is very stable for the thin 
wire material, and the magnetization reverses very steeply at an instant 
when the external magnetic field attains a critical value. This very 
special characteristic, large Barkhausen reversal generates a very steep 
pulse voltage in the detection coil. Then, frequency of the induced 
voltage is analyzed, and the existence of the marker is recognized 
according to an amplitude and/or a ratio of a harmonic thereof, and it is 
decided if a warning is necessary or not. 
These markers provided at first had a relatively large size, but recently 
compact marker are desired. However, a magnetic property of a magnetic 
material is closely related to its shape, and it is hard to produce a 
compact marker. For example, in the system mentioned above, an Fe-based 
amorphous thin wire of length of about 90 mm is used. Generally, when a 
magnetic material is magnetized, magnetic poles appear at two ends 
thereof, and a magnetic flux of a opposite direction to the applied 
magnetic field is generated from the magnetic poles, and it affects the 
magnetic material itself. This is called usually as demagnetizing field, 
and it operates as a resistance against the magnetization of the material 
along the applied magnetic field. In the above-mentioned metallic wire, 
magnetic properties are deteriorated due to demagnetizing magnetic field 
if its length is equal to or less than about 90 mm. The demagnetizing 
field increases with increase in a ratio of cross sectional area to 
length. Then, in order to reduce the effect of the demagnetizing field, a 
thinner wire may be used. However, as the diameter of the wire decreases, 
the total volume thereof decreases and a sufficient amount of magnetic 
flux cannot be obtained, and a voltage induced in the detection coil 
decreases. Then, the marker cannot be so narrow. 
Japanese Patent laid open Publication discloses a method to solve this 
problem. As to a metallic thin wire, a demagnetizing field is generated 
due to free magnetic poles at two ends. Then, as shown in FIG. 3, the 
formation of magnetic poles at ends of the thin wire can be prevented by 
contacting soft magnetic plates at two ends of the metallic thin wire to 
combine magnetically the thin wire with the soft magnetic plates. The 
effect of demagnetizing field on the wire is reduced, and even a thinner 
wire can have sufficient good magnetic characteristics. It is described 
that the plates made of a soft magnetic material is preferably produced by 
cutting an amorphous metallic thin ribbon. As the sizes of the plates made 
of a soft magnetic material increase, a critical field for magnetization 
reversal increases. Then, it is described that a sum of the lengths of the 
two plates is equal to or less than 50% of a length of the wire. Such a 
marker can be produced for example. Amorphous thin ribbons which have been 
cut beforehand are supplied onto a continuous amorphous wire at 
appropriate positions, and they are guided between two films and layered 
by a roller. 
As described above, a compact magnetic marker can be produced by providing 
plates made of a soft magnetic material at two ends of a metallic wire. 
However, a structure of the magnetic marker is complicated, and steps for 
manufacturing it becomes large. Then, it is desirable to provide a 
magnetic marker having a simpler structure and easy to be fabricated. 
SUMMARY OF THE INVENTION 
An object of the invention is to provide a compact magnetic marker used for 
an electronic article surveillance and/or identification system and a 
manufacturing method therefor. 
A magnetic marker of the invention comprises a wire member made of a first 
magnetic material and a plane member made of a second magnetic material, 
the plane member having uniaxial magnetic anisotropy. The wire member 
contacts substantially to the plane member, and an angle .theta. of a 
magnetic easy axis of the plane member relative to a longitudinal 
direction of the wire member is between 40.degree. and 90.degree.. The 
angle is 0.degree. when the wire member is parallel to the magnetic easy 
axis. It increases as the wire member becomes nonparallel to the magnetic 
easy axis, and it reaches finally to 90.degree. when the wire member is 
perpendicular to the magnetic easy axis. The wire member can be magnetized 
in both longitudinal directions. Then, a slate with an angle .theta. is 
equivalent magnetically to a state with an angle (180.degree.-.theta.) by 
reversing magnetization of the wire member or the plane member. For 
example 40.degree. is equivalent to 140.degree.. In this sense, the angle 
of the longitudinal direction of the wire relative to the magnetic easy 
axis of the plane member is specified between 0.degree. and 90.degree., 
and it has a maximum at 90.degree.. 
In order to operate the magnetic marker effectively, the wire member is 
arranged to have the above-mentioned angle relative to the direction of 
magnetic anisotropy of the plane member to combine them magnetically. 
Especially, the magnetic marker operates well When the longitudinal 
direction of the wire member is perpendicular to the magnetic easy axis of 
the plane member. A substantially effective voltage is induced in a search 
coil according to a change in magnetic field along any direction in a 
plane including the plane member. Therefore, the magnetic marker can 
respond to an alternating magnetic field along all the direction in a 
plane including the magnetic marker. The wire member itself does not 
generate steep magnetization reversal due to demagnetizing field if its 
length is not sufficiently long. However, if such a wire member is 
combined with the plane member, steep magnetization reversal is possible 
to be used as a magnetic marker. 
Preferably, the first magnetic material of the wire member or the second 
magnetic material of the plane member includes at least 50% of amorphous 
phase. Then, the wire member or the plane member has a magnetic property 
appropriate for a magnetic marker. 
Preferably, the plane member comprises a film formed on a flexible 
substrate, the film having a thickness between 0.1 and 10 .mu.m. If the 
thickness is equal to or less than 10 .mu.m, a magnetic field at which 
magnetization reversal occurs is not so large, while if it is equal to or 
larger than 0.1 .mu.m, the magnetic effect is sufficient large. 
Preferably, the wire member contacts substantially to the plane member to 
cause large Barkhausen reversal against a change in external magnetic 
field. Thus, steep magnetization reversal is generated. Particularly, if 
both wire and plane members have large Barkhausen reversal, the magnetic 
marker responds steeply according to an alternating magnetic field along 
all the direction in a plane where the magnetic marker exists, and 
superior recognition property can be provided. 
In a method for manufacturing a magnetic marker of the invention, a wire 
made of a first magnetic material is formed continuously. A continuous 
planar magnetic material (web) made of a second magnetic material which 
enable to have an uniaxial magnetic anisotropy is formed, and the magnetic 
easy axis of the web is induced to have an angle between 40.degree. and 
90.degree. relative to a longitudinal direction of the wire. Next, the 
continuous wire is lapped on the web so that the wire contacts 
substantially to the plane member, and the continuous wire is adhered to 
the web with an adhesive agent or the like. Then, the continuous wire and 
web adhered to each other are cut in magnetic markers. Each magnetic 
marker comprises a wire member made of a part of the wire and a plane 
member made of a part of the web. 
Because the magnetic easy axis of the plane member has an angle between 
40.degree. and 90.degree. relative to the longitudinal direction of the 
wire, the web can also be supplied continuously, and markers can be 
produced very simply. If the angle is less than 40.degree., the marker 
produced has a bad property by layering the web material and the 
continuous wire in parallel. Then, it is needed to layer them by 
intersecting each other at an appropriate angle, but this makes it very 
difficult to produce markers continuously. The above-mentioned 
manufacturing method has no such difficulty. Preferably, in fixing the web 
and the continuous wire, a first adherent tape, a web, a continuous wire 
and a second adherent tape are supplied in parallel to overlap them by a 
roller due to adherence. Thus, the web and the continuous wire can be 
fixed to each other easily by contacting to each other substantially. 
An advantage of a magnetic marker of the present invention is that a 
compact magnetic marker having superior properties can be provided with a 
simple structure. 
An advantage of a manufacturing method of the invention is that the 
magnetic marker can be produced continuously by using an apparatus having 
a simple structure so that this method can be used commercially.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
First, as a comparison example, the inventors examine a magnetic marker 
where a wire (wire member) on a continuous soft magnetic ribbon. Amorphous 
alloy thin ribbons 2705M (Co-based alloy, no magnetostriction) and 2605S2 
(Fe-based alloy, positive magnetostriction) of Allied Signal of thickness 
of about 20 .mu.m are used as the soft magnetic thin ribbon. Though it is 
not subjected to annealing, the coercive force is as small as about 0.1 
Oe, and no magnetic anisotropy is observed except that due to its shape. 
Though shapes of the ribbon and the wire and arrangement thereof are 
changed in various ways, a magnetic field of the magnetic marker necessary 
for the wire to reverse magnetization becomes very large, and it cannot be 
used practically as a marker. This is similar to a marker shown in the 
above-mentioned Japanese Patent laid open Publication 195384/1992 where 
the sizes of the soft magnetic pieces at two ends of the wire is 50% or 
more of the length of the wire. Therefore, a marker as a simple 
combination of a soft magnetic ribbon with a wire cannot be used. 
The inventors further examine a marker as a combination of a wire with a 
soft magnetic thin film. In general, the magnetic thin film can be 
controlled its property according to deposition conditions. Then, besides 
the shapes of the thin film, various factors such as coercive force, 
saturation magnetic flux density, squareness of hysteresis, magnetic 
anisotropy or magnetic domain structure are also examined in detail. As a 
result, it is found that the effect of magnetic anisotropy is large 
especially. Further, it is also found that a marker having properties 
similar to those of previous markers can be obtained by using an 
appropriate structure, and the present invention can be attained. 
Referring now to the drawings, wherein like reference characters designate 
like or corresponding parts throughout the several views, FIGS. 1 and 2 
show a magnetic marker of an embodiment of the invention comprising a wire 
member 21 and plane member 22. An angle of the magnetic easy axis 24 of 
the plane member 22 relative to the longitudinal direction of the wire 
member 21 is between 40.degree. and 90.degree.(90 in an example shown in 
FIG. 2), and the two members 21 and 22 contact directly with each other. 
(As shown in the exploded view of FIG. 1, the wire member 21 and the plane 
member 22 are inserted between two films 23 and 3.) 
The plane member 22 having uniaxial magnetic anisotropy is made of a 
magnetic material. In order to obtain a uniaxial magnetic material, 
orientation of crystal grains, deposition or annealing in magnetic field, 
application of uniaxial stress, patterning or the like is effective. For 
example, U.S. Pat. No. 5,181,020 describes a very simple method for 
controlling uniaxial magnetic anisotropy of thin film, wherein a cathode 
is arranged obliquely relative to a substrate when a thin film is 
deposited with sputtering. This can be used very simply for a flexible 
substrate. 
The wire member 21 has to be arranged at an appropriate position on the 
anisotropy direction of the plane member 22 in order to operate 
effectively in the magnetic marker. It is needed that the wire member 21 
is combined magnetically with the plane member 22. The magnetic marker 
operates well preferably when the magnetic easy axis of the plane member 
22 is perpendicular to that of the wire member 21, while it does not 
operate practically when the magnetic easy axis of the plane member 22 is 
in parallel to that of the wire member 21. Between the two extreme cases, 
the magnetic marker operates well when the magnetic easy axis of the plane 
member 22 has an angle in a range between 40.degree. and 90.degree. 
relative to that of the wire member 21. In the magnetic marker of the 
embodiment, the magnetic easy axis of the wire member is generally in 
parallel to its longitudinal direction. Then, the magnetic marker of the 
embodiment is summarized as follows: In the magnetic marker, it is 
necessary that an angle of the axis 24 of easy magnetization of the plane 
member 22 relative to the longitudinal direction of the wire member 21 has 
a value between 40.degree. and 90.degree.. In order to use the plane 
member 22 with the wire member 21, it is preferable that the angle has a 
value between 60.degree. and 90.degree., and most preferable that he angle 
is 90.degree.. The magnetic easy axis can be measured with a torque meter, 
a B-H tracer or the like by changing a direction of applied magnetic 
field. In the embodiment, average magnetic properties of the materials 
rather than local and precise ones are important factors, and anisotropy 
dispersion due to skew or ripples are allowed to some degree. Therefore, 
the above-mentioned measurement can be adopted. The invention will be 
explained below by using measured values obtained with a B-H tracer. 
Magnetic materials for the wire and plane members 21 and 22 may be an 
amorphous material as well as a crystal-line material such as a permalloy. 
Especially, an amorphous material is superior in that it has a small 
coercive force and that magnetic anisotropy can be controlled easily by 
magnetic field annealing. It is preferable that the wire member 12 and/or 
the plane member 22 comprises at least an amorphous material of 50% or 
more. If an amount of the amorphous material is 50% or more, magnetic 
properties appropriate for the magnetic marker can be obtained. 
Further, magnetostriction can be controlled from positive to negative one 
by controlling the composition, and a material having a steep 
magnetization reversal can be obtained by an appropriate processing. For 
example, an Fe-based amorphous metallic wire described in Japanese Patent 
Publication 27958/1991 has a large positive magnetostriction of 10.sup.-5 
or more, and magnetization along the normal and reverse directions on the 
longitudinal direction becomes very stable by realizing a special magnetic 
domain structure. Large Barkhausen reversal is induced by the magnetic 
domain structure. Large Barkhausen reversal is also observed in amorphous 
thin ribbons and amorphous thin films besides the above-mentioned 
amorphous wires, as described in U.S. Pat. Nos. 4,980,670 and 5,181,020. 
Several mechanisms are known to generate the large Barkhausen reversal, 
and it is observed for materials having positive, zero and negative 
magnetostriction. In the embodiment, it is very preferable to use a 
material having large Barkhausen reversal. Especially, the wire member and 
the plane member are made of magnetic materials having large Barkhausen 
reversal, steep magnetization reversal occurs for a external magnetic 
field along any direction in a plane including the magnetic marker, and a 
detection signal is generated. This is ascribed to that the magnetic easy 
axis of the wire and plane members crosses each other in the magnetic 
marker of the invention. In case of a prior art magnetic marker comprising 
only a wire or a prior art magnetic marker comprising a wire and plate 
pieces at two ends of the wire, if a magnetic field is applied along a 
direction perpendicular to the wire, magnetization reversal does not 
occur. This causes a dead angle in a surveillance area. Then, this problem 
is solved by using a special coil to generate magnetic fields along 
various directions. The magnetic marker responds to a magnetic field along 
all the direction and has no such problem, or it needs no special coil. 
In the embodiment, it is needed that the wire member 21 and the plane 
member 22 need to contact to each other to be combined magnetically, and a 
sheet or the like should not be inserted between them. However, it is 
effective to apply a coating of oil, or the like to the wire member 21 in 
order to prevent an unnecessary stress to the wire member 21, and this is 
included in a scope of the invention. In this sense, the wire member 21 
and the plane member 22 contact substantially directly to each other. A 
magnetic marker of this embodiment comprises a wire member 21 made of a 
metallic thin wire of circular cross section, a metallic ribbon having a 
very narrow width, a metallic thin film made with patterning or the like, 
and a plane member 22 made of a metallic thin ribbon or a metallic thin 
film, the wire member 21 being applied directly to the plane member 22. 
However, when the plane member 22 is made of a metallic ribbon, a shape or 
characteristic thereof has to be determined carefully. As described later 
on a third comparison example, when a wire is lapped on an amorphous 
metallic thin ribbon of thickness of 20 .mu.m without giving magnetic 
anisotropy, a magnetic field needed to reverse magnetization becomes too 
large to be used as a magnetic marker practically. This phenomenon can be 
avoided by decreasing the thickness of the thin ribbon or by giving strong 
magnetic anisotropy. Though the metallic thin ribbon may be used as the 
plane member 22, it is not easy to decrease the thickness of the thin 
ribbon or to give strong magnetic anisotropy. Then, preferably, the plane 
member 22 comprises a metallic thin film, and the wire member 21 comprises 
a metallic wire having a circular cross section. Especially, an amorphous 
metallic wire has superior soft magnetic properties, and it can be formed 
to decrease diameter form about 200 .mu.m to several m easily by using die 
drawing. Further, an amorphous metallic wire having magnetostriction has 
better squareness of magnetization hysteresis than that having zero 
magnetostriction, and can be used effectively in a magnetic marker. 
A thin film used as the plane member 22 has no effect if its thickness is 
too thin, while a thick film having a thickness larger than 10 .mu.m is 
not desirable because the critical magnetic field of magnetization 
reversal of the wire becomes large. The thickness of the thin film has a 
value preferably between 0.2 and 5 .mu.m, more preferably between 0.3 and 
2 .mu.m because the amount of expensive thin film can be reduced while a 
sufficient advantage as the magnetic marker can be obtained. Then, most 
preferably, a metallic thin film formed on a flexible substrate such as 
polymer and having a thickness of 0.1-10 .mu.m is contacted directly to an 
amorphous wire having a magnetostriction and adhered with a pressure 
sensitive adhesive. 
The above-mentioned magnetic marker comprises one wire member and one plane 
member. Next, a magnetic marker comprising a plurality of wire member and 
one plane member is explained. In an example shown in FIG. 19, a magnetic 
marker comprises two magnetic wires 45' and 45" and one magnetic thin film 
48. In this embodiment, because the magnetic marker comprises a plurality 
of wire member, it can add high functions. As explained above, a wire 
member reverses magnetization according to an external magnetic field to 
generate a magnetic pulse as a signal to be detected. If a plurality of 
wire member is included in the magnetic marker, a plurality of magnetic 
pulses is generated. In order to detect each magnetic pulse of the wire 
member independently of each other, a timing to generate the pulse is 
changed, and this is controlled by changing a magnetic field needed for 
magnetization reversal. The demagnetizing field of the wire member depends 
on the composition thereof, production conditions, annealing and the like. 
It depends on the length even the same material is used. Further, if thin 
wire members are arranged on the plane member as in this embodiment, the 
wire member interact with each other, and there is a tendency that the 
magnetic pulses are separated. Thus, the pulse signals can be controlled 
relatively easily. The plurality of magnetic pulses improves a performance 
of correct identification by the marker remarkably. Magnetic pulse signals 
of a predetermined number and at different timings, responding to an 
alternating magnetic field generated in a surveillance area, can be 
discriminated easily from noise signals due to other magnetic material 
such as an iron plate. It is also possible to add identity to a marker by 
using a plurality of magnetic pulse signals. Recognition signals of a few 
to a few tens of bits can be generated by changing a combination of a 
plurality of wire member or by controlling a number of magnetic pulses and 
timings to be responded. Such a marker is advantageous for a system for 
selecting goods without contact. It is an advantage of the marker that the 
above-mentioned high functions can be realized by using a simple structure 
where a plurality of wire members is arranged on a plane member. 
The magnetic marker explained above is manufactured by a new method as will 
be explained below. In this manufacturing method, uniaxial magnetic 
anisotropy is given to a continuous web made of a magnetic material so 
that an angle of magnetic easy axis of the web relative to a longitudinal 
direction of a web is between 40.degree. and 90.degree.. Next, the 
continuous wire is lapped on the web to contact substantially to each 
other. Then, the continuous wire is fixed to the web with a pressure 
sensitive adhesive or an adhesive agent. Then, the continuous wire and the 
web are cut in desired sizes. The manufacturing method will be explained 
below in detail. 
In the manufacturing method, first, a continuous wire and a web are 
provided. Next, uniaxial magnetic anisotropy is given to the web. The web 
is, for example, a metallic ribbon or thin film which will be used as the 
plane member of a magnetic marker after cutting. When the uniaxial 
magnetic anisotropy is given, a magnetic easy axis of the web has an angle 
between 40.degree. and 90.degree. relative to a longitudinal direction of 
the web. There is no restriction on the inducement of the uniaxial 
magnetic anisotropy. For example, it is effective for a thin film to apply 
a magnetic field on deposition, or to arrange apparatus for deposition so 
that evaporated particles deposit obliquely. Annealing in applied magnetic 
field or under applied stress to a metallic thin film or ribbon is also 
advantageous to induce good uniaxial magnetic anisotropy. As to permalloy, 
it is known that uniaxial magnetic anisotropy is induced by rolling. 
Uniaxial magnetic anisotropy can be induced along a desired direction by 
using these processes. Further, such a web can also be produced by cutting 
a material having a direction not specified to satisfy the above-mentioned 
condition. 
Next, the continuous wire is lapped on the web. If the web comprises a 
magnetic thin film, the marker can be manufactured with an apparatus, for 
example, as shown in FIG. 3. A sheet 23, a wire 21' for forming the wire 
member and another sheet 3 are supplied in parallel. A magnetic thin film 
22' has been formed on a side of the sheet (flexible substrate) 23 to 
which the wire 21' contacts directly (refer to FIG. 2), and the magnetic 
easy axis 24 of the magnetic thin film has an angle between 40.degree. and 
90.degree. relative to a longitudinal direction of the sheet 23. As shown 
in FIG. 1, the sheet 3 is a double side pressure sensitive adhesive tape 
comprising a base 5 having adhesives 14a, 14b applied to two sides 
thereof, and a separation paper 6 at the lower side thereof. The metallic 
wire 21' is located between the films 3 and 23, and they are layered 
together by a pair of rollers 26. The layered sheets are supplied further 
to be cut at desired pattern by a pair of cut rollers 27 and wound on a 
bobbin. A user in a shop or the like separates a marker 20 from the 
separation paper 6 and sticks it to a good to be detected. The marker 20 
comprises a wire member 21 made of a portion cut from the wire 21' and a 
plane member 22 made of a portion cut from the magnetic thin film 22' If a 
magnetic marker is used as a tag without adherence, a single-side pressure 
sensitive adhesive tape may be used for the film 3. 
FIGS. 4 and 5 show an example of a magnetic marker comprising a magnetic 
ribbon as the plane member. As shown in FIG. 4, the marker has a structure 
where a wire member 21 is lapped on a plane member 32 and they are further 
interposed by sheets 3 and 31. The sheet 31 has a pressure sensitive 
adhesive tape 33 applied to a side facing the wire member 21. The magnetic 
easy axis 34 (FIG. 5) of the plane member 32 has an angle between 
40.degree. and 90.degree. relative to a longitudinal direction of the wire 
21o The sheet 3 is a double side pressure sensitive adhesive tape similar 
to that shown in FIG. 1. 
As shown in FIG. 6, when the magnetic marker is manufactured, a sheet 31, a 
wire 21' of a circular cross section for the wire members, a magnetic thin 
ribbon 32' for the plane members and another sheet 3 are supplied in 
parallel. A roller 35 is arranged oppositely to a bobbin of the sheet 31. 
Then, they are layered by a pair of rollers 36, cut at desired patterns by 
a pair of cut rollers 37 and wound on a bobbin shown at the right side in 
FIG. 6. A user in a shop or the like removes one of the markers 30 from 
the separation paper 6 and sticks it to a good. The marker 30 comprises a 
wire member 21 made of a portion cut from the wire 21' and a plane member 
32 made of a portion cut from the magnetic ribbon 32'. 
FIGS. 3 and show apparatuses for manufacturing an linear array of magnetic 
markers. However, a plurality of linear arrays of magnetic markers can be 
manufactured if a plurality of wires 21 are supplied in parallel and a 
number of blades to be put in the cutting roller corresponds to the number 
of the wires 21. This enhances production speed. 
Examples of magnetic markers are explained below. 
EXAMPLE 1 
A marker shown in FIG. 7 is manufactured by using a metallic thin film and 
a metallic thin wire for the plane member and the wire member. The marker 
comprises a plane member 43 made of a metallic thin film and a wire member 
42 made of a metallic wire. The thin film has a thickness of 1.0 .mu.m and 
a composition of (Co.sub.0.94 Fe.sub.0.06).sub.72.5 Si.sub.12.5 B.sub.15 
(atomic percent), and it is deposited by sputtering on a polyethylene 
telephthalate (PET) substrate of thickness of 50 .mu.m with applying a 
magnetic field generated by permanent magnets. The PET substrate with the 
thin film is cut to have a length of 40 mm and a width of 10 mm so that 
the longitudinal direction of the metallic wire is perpendicular to the 
magnetic easy axis of the metallic thin film. On the other hand, the 
metallic wire of (Co.sub.0.5 Fe.sub.0.5).sub.78 Si.sub.7 B.sub.15 (atomic 
percent) having a diameter of 125 .mu.m is produced with an apparatus by 
melt spinning in rotating water, and it is processed to a wire of diameter 
of 100 .mu.m by cold die drawing. Then, it is cut to have a length of 40 
mm to be used as the wire member. The apparatus is described for example 
in Japanese Patent Publication 9906/1989. The metallic thin film and the 
metallic wire are identified as an amorphous phase with an X ray 
diffraction apparatus of Rigaku Denki model RAD-rB. The wire member 42 and 
the plane member 43 are combined so as to contact directly with each other 
by arranging their longitudinal directions in parallel. The wire member 42 
is placed at the center of the PET substrate, and it is fixed by adhering 
a single side pressure sensitive adhesive tape (Scotch mending tape 810 of 
Sumitomo-3M) thereon. 
Magnetic characteristics of the marker produced as described above are 
measured with an alternating B-H tracer o AC, BH-100K of Riken Denshi at 
60 Hz, and frequencies of magnetic pulses are analyzed with a dynamic 
signal analyzer 3562A of Hewlett Packard at 50 Hz and at 1 Oe of 
alternating magnetic field. FIG. 8 shows magnetization of the marker when 
an alternating magnetic field of 60 Hz is applied along the longitudinal 
direction, wherein the ordinate represents magnetization. The marker shows 
very steep Large Barkhausen reversal at 0.26 Oe. FIG. 9 shows BH loop when 
magnetic properties of only the wire (wire member 42) used in the marker 
is measured along the longitudinal direction. It is apparent that it 
becomes harder to be magnetized due to the influence of the demagnetizing 
field and large Barkhausen reversal is prevented. FIG. 10 shows magnetic 
characteristic of only the thin film (the plane member 43) (a) along the 
longitudinal direction and (b) along the width direction, measured 
similarly. It is apparent that the magnetic easy axis 44 is perpendicular 
to the longitudinal direction of the wire. Therefore, it is found that 
even if the short wire (wire member 42) having bad magnetic properties by 
itself (refer to FIG. 9) is combined with a thin film (the plane member 
43) having magnetic hard axis (refer to FIG. 10), an influence of 
demagnetizing field is reduced and Large Barkhausen reversal is realized. 
Next, magnetic pulses of a marker under an alternating magnetic field of 1 
Oe of 50 Hz are evaluated from a voltage induced in a search coil wound 
around the marker. A waveform of the magnetic pulses are subjected to 
Fourier analysis for frequency analysis, and an amplitude of a harmonic 
and the like are analyzed. FIGS. 11 and 12 show some results. FIG. 11 
shows a waveform of the induced voltage, and a very steep single pulse is 
observed. FIG. 12 shows Fourier analysis of the pulse shown in FIG. 11, 
and this shows that very higher harmonics are observed. On the other hand, 
when only the wire 42 is measured, the induced voltage comprises a 
plurality of waveforms, and amplitudes of signals of high frequencies are 
very small. That is, bad signals are observed. 
As explained above, a compact superior magnetic marker can be obtained by 
contacting the wire member and the plane member with each other so that 
magnetic easy axis thereof are perpendicular to each other. 
COMISON EXAMPLE 1 
A marker is manufactured similarly to Example 1 except that magnetic easy 
axis thereof are in parallel to each other. FIG. 13 shows magnetization 
property of the marker when an alternating magnetic field of 60 Hz is 
applied along the longitudinal direction thereof. The ordinate represents 
magnetization. The magnetization property is almost the same as that of 
only the thin wire shown in FIG. 9, and an advantage of the combination 
with the thin film is not observed. That is, if magnetic easy axis thereof 
are in parallel to each other, a marker of good characteristic cannot be 
obtained when the size of the thin wire becomes small. 
EXAMPLE 2 AND COMISON EXAMPLE 2 
Markers are manufactured similarly to Example 1 except that an angle of the 
magnetic easy axis of the plane member 43 relative to the longitudinal 
direction of the wire member 42 is changed from 10.degree. to 80.degree.. 
Magnetic characteristic is measured by applying an alternating magnetic 
field of 60 Hz along the longitudinal direction of these magnetic markers. 
In a range between 40.degree. and 80.degree., the magnetization is 
reversed steeply at almost one stage, similarly to Example 1. On the 
contrary, if the angle becomes smaller than 40.degree., the magnetization 
of the wire member 42 changes at a plurality of steps, going toward a 
continuous magnetization change. FIGS. 14 and 15 show alternating 
magnetization characteristic at 30.degree. and at 40.degree., wherein the 
ordinate represents magnetization. At angles of 40.degree. (FIG. 14) or 
more, discontinuous characteristic is observed, similarly to Example 1, 
whereas at angles of 30.degree. (FIG. 15) or less, the magnetization 
reversal is gradual, and the squareness is deteriorated. These data shows 
that a compact superior magnetic marker can be obtained by contacting the 
wire member and the plane member with each other so that an angle of the 
magnetic easy axis of the wire member relative to that of the plane member 
is between 40.degree. and 90.degree.. 
COMISON EXAMPLE 3 
An amorphous Co-based alloy ribbon MBF-2705M of Allied Signal is cut along 
a roll direction by 40 mm of length and 10 mm of width, to be used as the 
plane member. It has a thickness of about 20 .mu.m, and the material 
itself has no magnetic anisotropy except slight anisotropy due to its 
shape. A wire of 40 mm of length used in Example 1 is put at the center of 
the ribbon by aligning their longitudinal directions in parallel, and they 
are fixed with a Scotch tape. Magnetic characteristic of the marker is 
measured by applying alternating magnetic field of 60 Hz along the 
longitudinal direction of the marker. As shown in FIG. 16, because the 
thin ribbon having a volume as large as several tens times that of the 
marker of Example 1 is magnetized at the same time, a change of 
magnetization becomes smaller relatively, and a magnetic field needed to 
reverse the magnetization of the wire increases to 1.5 Oe. This means that 
a large change in magnetic field is needed to generate a detection signal, 
or a performance as a magnetic marker is deteriorated. Thus, a compact 
superior magnetic marker cannot be obtained as a combination of a thin 
wire with a thin ribbon having almost no magnetic anisotropy. 
EXAMPLE 3 
A magnetic marker shown in FIG. 7 is manufactured by using a thin wire of 
(Co.sub.0.5 Fe.sub.0.5).sub.78 Si.sub.7 B.sub.15 (atomic percent) of 
diameter of 100 .mu.m and length of 35 mm, as the wire member 42, and a 
permalloy thin film of width of 15 mm and length of 40 mm, as the plane 
member 43. The permalloy thin film is prepared to a thickness of 0.5 .mu.m 
on a polyethylene telephthalate substrate of thickness of 125 .mu.m using 
DC sputtering in magnetic field with a Ni.sub.70 Fe.sub.30 (atomic 
percent) target. The longitudinal direction of the wire member 42 is 
perpendicular to the magnetic easy axis of the plane member 43. FIG. 17 
shows alternating magnetization property along the longitudinal direction 
of the magnetic marker. Large Barkhausen reversal is obtained by combining 
the wire member 42 with the plane member 43, and a performance as the 
magnetic marker is improved. That is, even if the plane member comprises a 
crystalline material, a compact superior magnetic marker can be obtained 
by using an appropriate direction of magnetic anisotropy. 
EXAMPLE 4 
A magnetic marker shown in FIG. 7 is manufactured by using an amorphous 
ribbon as the wire member 42 and a permalloy thin film as the plane member 
43. The wire member 42 is an amorphous Co-based alloy thin ribbon 
MBF-2705M of Allied Signal which is cut by 20 mm of length and 1 mm of 
width. The plane member 43 is a Ni.sub.70 Fe.sub.30 (atomic percent) thin 
film of thickness of 1 .mu.m, width of 10 mm and length of 40 mm. By 
putting the ribbon directly on the thin film, and they are fixed with a 
single-side adherent tape. At this time, the thin ribbon is arranged 
perpendicular to the magnetic easy axis of the thin film. FIG. 18 shows 
alternating magnetization characteristic (b) along the longitudinal 
direction of the marker. For comparison, alternating magnetization 
characteristic (a) along the longitudinal 
direction of only the ribbon (wire member) before combining with the 
magnetic thin film. It is observed that the magnetic characteristic (a) of 
the wire member, wherein magnetization is hard due to demagnetizing field 
before combination, changes almost to halve the saturation field by the 
combination with the plane member 43, or a performance as the marker is 
improved. 
EXAMPLE 5 
A magnetic marker shown in FIG. 19 is manufactured by using two wire 
members and one sheet of a plane member. The wire members 45' and 45" are 
amorphous wires of (Co.sub.0.5 Fe.sub.0.5).sub.78 Si.sub.7 B.sub.15 
(atomic percent) of diameter of 100 .mu.m and length of 35 mm. A Ni.sub.70 
Fe.sub.30 (atomic percent) permalloy thin film of thickness of 0.5 .mu.m 
is prepared on a PET substrate of thickness of 100 .mu.m, as the plane 
member 43, and it is cut by 40 mm times 10 mm so that the width direction 
agrees to the magnetic easy axis 47. The two thin wires 45' and 45" are 
put with a distance of 2 mm along the longitudinal direction of the thin 
film 48, and they are fixed with a single side adherent tape. FIG. 20 
shows a waveform of a magnetic pulse induced in a search coil when an 
alternating magnetic field of 50 Hz of 1 Oe is applied. Two steep pulse 
voltages are generated with a time distance of about 2 msec. The two 
pulses can be distinguished easily because each pulse signal is 
sufficiently clear. Because magnetic pulses having good signal 
characteristics are detected independently of each other, a number of 
pulses and time distances between them are also used as an information 
besides the amplitude of harmonic signals. Therefore, recognition 
performance of the marker is improved remarkably if compared with a marker 
comprising one wire member. As explained above, by contacting a plurality 
of wire members with a plane member so that the magnetic easy axis of the 
wire magnets are perpendicular to that of the plane member, a plurality of 
independent magnetic pulses is generated, and a compact superior magnetic 
marker can be obtained. 
EXAMPLE 6 
Magnetic markers are manufactured by using the apparatus shown in FIG. 3. 
The sheet 23 shown in FIG. 3 is a polyethylene telephthalate (PET) 
substrate of thickness of 50 .mu.m, and an amorphous thin film 22' of 
(Co.sub.0.94 Fe.sub.0.06).sub.72.5 Si.sub.12.5 B.sub.15 (atomic percent) 
of thickness of 0.5 .mu.m is formed thereon. The wire 21' is an amorphous 
wire of (Co.sub.0.5 Fe.sub.0.5).sub.78 Si.sub.7 B.sub.15 (atomic percent) 
of diameter of 100 .mu.m. These corresponds to the counterparts used in 
Example 1. The sheet 3 is a double side adherent tape applied with an 
adherent agent and attached with separation papers at both sides. Though 
not shown in FIG. 3, the paper at the upper side is removed when the sheet 
3 is supplied, but the paper at the lower side is kept to be attached. 
These materials are supplied in parallel from each bobbin, adhered by the 
roller, cut at a rectangular pattern of length of 40 mm and width of 10 mm 
by the cut rollers and wound on the bobbin. A sheet of the magnetic marker 
20 is removed from the layered tape manufactured as explained above, and 
magnetic properties thereof is measured. A good performance as in Example 
1 is observed. 
Although the present invention has been fully described in connection with 
the preferred embodiments thereof with reference to the accompanying 
drawings, it is to be noted that various changes and modifications are 
apparent to those skilled in the art. Such changes and modifications are 
to be understood as included within the scope of the present invention as 
defined by the appended claims unless they depart therefrom.