JP3058899B2 - Magnetic sensing element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic sensing element for detecting magnetism using a ferromagnetic magneto-resistance effect in which the electrical resistance of a ferromagnetic material changes under the influence of a magnetic field. It is about.

[Prior Art] A conventional magnetic sensing element (1) has a structure as shown in FIG.
A resistor (3) for detecting a magnetic field (hereinafter abbreviated as a detection resistor) and a resistor (4) for a temperature compensation (hereinafter abbreviated as a compensation resistor) are provided on the surface of the nonmagnetic substrate (2). ), Input terminals (5) and (6), and an output terminal (7).

The detection resistor (3) is formed by connecting a number of parallel strips (8) of a ferromagnetic magnetoresistive material whose electric resistance changes with the strength of the magnetic field in series, and each of the strips (8) has a width. Is formed to have a length of W. The compensating resistor (4) has strips (9) of the same length, width and number as the strips (8) of the detection resistor (3) connected in series. The direction is formed at right angles to the strip portion (8), and one end of the resistor (3) and one end of the resistor (4) are connected.

The input terminals (5) and (6) are formed of an electric conductor and are respectively coupled to the other ends of the resistors (3) and (4).

The output terminal (7) is formed of a good electrical conductor,
It is connected to the connection point between the resistors (3) and (4).

This magnetic sensing element (1) is used as a proximity switch (10) as shown in FIG. 26, for example. This proximity switch (10) is composed of a magnetic detection element (1) and a signal processing circuit (1).
The circuit board (12) on which 1) is mounted is incorporated into a housing (13) molded of resin or the like, and input / output signal cables (14)
Is installed. The wiring between the magnetic sensing element (1) and the circuit board (12) is electrically connected by a gold wire (15).

FIG. 27 shows a circuit diagram of the proximity switch (10). This circuit, power E ₀ is coupled to an input terminal of the magnetic sensor (1) (5) (6), the series circuit of the magnetic detection element (1) parallel with the resistor (16) variable resistance (17) Are connected, the junction (output terminal) (7) of the detection resistor (3) and the compensation resistor (4), the resistor (16) and the variable resistor (1).
The connection point (18) of (7) is input to the differential amplifier (19) to form a Wheatstone bridge (hereinafter abbreviated as bridge). Further, the output V _A of the differential amplifier (19) is inputted to the comparator (20) of the threshold V _T.

The proximity switch (10) adjusts the variable resistor (17) in the absence of a magnetic field so that the output _VA of the differential amplifier (19) becomes zero, that is, the bridge is balanced, For example, as shown in FIG. 28, the cylinder (2) is used as a piston position detection switch for the small piston cylinder (21).
2) A resistor (3) (4) with a band (23) outside
Is fixed at the target detection position O.

Briefly explaining the configuration of the piston cylinder (21) in FIG. 28, a piston (24) is slidably fitted into the cylinder (22) without any gap, and the piston (24) has a ring shape. The piston (24) is connected to a driving device (not shown) outside the piston cylinder (21) by a rod (26).

[Problem to be Solved by the Invention] In the proximity switch (10) having the above-described configuration using the conventional magnetic sensing element (1), the output _VA of the differential amplifier (19) with respect to the position of the magnet (25) is: as shown in Figure No. 29 (a), and a sharp positive peak P ₁ in the center of the detection position O, the large negative peak P ₂ on both sides, further, a small positive peak P ₃ of the both sides It has a shape. Comparator (2
0) 1 When half the threshold V _T of the center of the peak P ₁ of the comparator (20) area where the output V ₀ is turned on (hereinafter, referred to as operating region) L is Figure 29 (b ),
Only about 2.5mm at the center can be obtained. For this reason, unless the proximity switch (10) is mounted at an extremely accurate position, the piston (24) cannot be detected, and the position adjustment requires a great deal of labor.

The output _VA of the differential amplifier (19) has a peak other than the center of the detection position O for the following reason.

In Figure 28, the magnet incorporated in the piston (24) (25) approaches the magnetic detection device (1), the magnetic field H _M of substantially arcuate This magnet (25) is generated, Figure 30 (a ), The light passes through the magnetic sensing element (1). At this time, as shown in an explanatory diagram of FIG. 30 (b), the detection resistor (3) and the compensation resistor (4) have respective strip portions (8).
The magnetic flux components Hx and Hy in the direction perpendicular to the longitudinal direction of (9) affect the resistance values of the detection resistor (3) and the compensation resistor (4), respectively, as shown in the static characteristics in FIG. , Its resistance value R decreases.

When the effects of the detection resistor (3) and the compensation resistor (4) on the output _VA of the differential amplifier (19) are individually decomposed, the output of the compensation resistor (4) becomes as shown in FIG. As shown,
There is a large negative peak P ₂ ′ on both sides of the center of the detection position O, and this peak substantially coincides with the negative peak P _{2 in} FIG. 29 (a). The output of the detection resistor (3) is shown in FIG.
, A positive peak P ₁ ′ at the center of the detection position O,
There is a small positive peak P ₃ ′ on the outside, and the central peak P ₁ ′ is slightly thicker than the central peak P _{1 in} FIG. 29 (a). Figure 29 peak P ₁ of the center of (a) is 32 view (b) peak P ₁ of the center of the 'become thinner than the peak P ₁ of the center of the 32 view (b)' Figure 32 is (A) two negative peaks P ₂ ′
This is because the peak is combined with the peak at the center of the detection position O, and the portion is cut off. As a result, the comparator (2
The operation area L of (0) is narrowed.

In addition, the output of the detection resistor (3) is larger than the output of the detection resistor (3) because the output of the compensation resistor (4) is reduced by _two negative peaks P ₂ ′ in FIG. 32 (a). Figure can not thickened central peak P ₁ 'of (b) is Figure 30 (a) since the magnetic field H _M as shown in the explanatory view of (b) of substantially arcuate magnet (25) is detected position O When located in the center of
The H _X H _M, but because the H _X << H _M only magnet (25) is slightly moved from the center of the detection position O. Therefore, it is difficult to secure a wide operation region L of the comparator (20).

If the compensating resistor (4) is simply regarded as one of the resistors constituting the bridge, it is preferable that the compensating resistor (4) is not affected by a magnetic field, and a non-magnetic metal such as Ti may be used. However, since the compensating resistor (4) is used for temperature compensation in pairs with the detecting resistor (3), the temperature coefficient of resistivity must be equal to that of the detecting resistor (3). At present, there is no such non-magnetic metal material, and even if there is a material similar to such a material, the compensation resistor (4) and the detection resistor (3) must be formed separately. However, there is a problem that the number of manufacturing steps increases.

Further, since the magnetic field H _M if the width D of the magnet (25) to approach the lateral substantially elliptical shape, the magnetic flux components perpendicular to the sensing resistor before and after the detection position O (4) increases, H _X H _M , H _Y 0 can be widened, and the operating range of the comparator (20) can be widened. However, conversely, the operating range of the piston (24) is reduced, and the operating speed of the piston (24) is reduced by increasing the frictional resistance. Therefore, the width D of the magnet (25) cannot be made too large.

Also, further, by lowering the threshold V _T of the comparator (20), although it is possible to widen the operating range L of the comparator (20) shown in Figure No. 29 (b), outer shown in Figure No. 29 (a) for receiving the impact of the positive peak P _3, it is less desirable to lower the threshold V _T.

An object of the present invention is to provide a magnetic sensing element for a proximity switch which does not have the above-mentioned disadvantages and has a sufficiently wide operating area.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and a plurality of elongated strip portions serving as current paths are folded back by using a ferromagnetic magnetoresistive material. The resistors for magnetic detection and temperature compensation, which are formed by connecting these strips in series, are formed on an insulating substrate so that the resistance values in a no-magnetic-field state are substantially equal to each other. Are arranged so that the average directions of the currents flowing through the respective strips constituting the resistors are substantially perpendicular to each other.These resistors for magnetic detection and temperature compensation are connected in series, and the approach of magnetism In a magnetic sensing element for detecting by a change in electric resistance of the magnetic detection resistor due to a resistance effect, a change in electric resistance due to a magnetoelectric resistance effect due to approach of magnetism is detected by the temperature compensation resistor. Body Smaller
Alternatively, the resistor for magnetic detection is made larger than the resistor for temperature compensation.

Specifically, the width of the strip portion of the temperature compensating resistor is formed narrower than the width of the strip portion of the detecting resistor, so that the change in electric resistance due to the magneto-resistance effect due to the approach of magnetism is magnetically detected. It is made smaller than the resistor for use.

Further, as another means, an angle θ formed by the strips on both sides of the magnetic detection resistor is 0 ° <θ ≦ 75 °, and a rectangular shape in which the strips on one side are respectively formed in parallel. Or the angle θ between the strips at both ends of the resistor for magnetic detection is arranged in a substantially fan shape in the range of 0 ° <θ ≦ 125 °, so that the magneto-resistance effect due to the approach of magnetism is obtained. The change in electrical resistance caused by the resistance is made larger than that of the resistor for temperature compensation.

[Operation] By reducing the width of the strip portion of the temperature compensation resistor to make the area smaller than the strip portion of the detection resistor, when the same magnetism is brought close to these resistors, the detection The resistance change of the temperature compensating resistor is smaller than the resistance change of the resistor, and it is desirable that there is no resistance change due to the influence of the magnetic field. The characteristics are close to ideal.

In addition, the detecting resistor may be arranged in a C shape in which the strip portions on one side are formed in parallel with each other, or the resistor may be formed by forming an angle between a part of the detecting resistor or the front strip portion. Is approximately fan-shaped so that the effect of the arc-shaped magnetic field is efficiently received, and within a desired range centered on the detection position, it is desirable that the magnetic field is more affected by the magnetic field. Are closer to ideal characteristics than before. Example A first example of the present invention will be described with reference to FIG. 1 to FIG.

In FIG. 1, (1a) has a detection resistor (3a), a compensation resistor (4a), input terminals (5) and (6) and an output terminal (7) formed on the surface of a glass substrate (2). It is a magnetic detection element.

The sensing resistor (3a) is a ferromagnetic magnetoresistive material
A plurality of parallel strips (8) are formed from a Ni-Fe alloy and formed by connecting the strips (8) in series. The strips (8) are about 1000 mm thick and 18 μm wide. Set to _A. The compensation resistor (4a) is formed of a plurality of strips (9) oriented at right angles to the strip (8) of the detection resistor (3a). the Fe alloy, a thickness of about 1000 Å, a width W _B of 6 [mu] m, and the resistance value of the compensating resistor (4a) and the detection resistor (3a) is formed in a substantially equal length l _B, the The area is the detection resistance (3
a) It is smaller than. One end of the compensation resistor (4a) and one end of the detection resistor (3a) are connected, and the output terminal (7) is connected to this connection point to be formed of an electric conductor. . The input terminal (5)
(6) is formed of a good electric conductor, and is respectively coupled to the other ends of the detection resistor (3a) and the compensation resistor (4a).

Next, the manufacturing process of the magnetic sensing element (1a) will be briefly described.

On a surface of a clean glass substrate (2), a Ni—Fe alloy, which is a ferromagnetic magnetoresistive material, is vacuum-deposited into a thin film having a thickness of about 1000 °.

The thin film other than the detection resistor (3a) and the compensation resistor (4a) is removed by photoetching, and the strip resistor (8) and the strip resistor (9) are connected to each other.
3a 3a) and the compensation resistor (4a) are formed.

After forming the detection resistor (3a) and the compensation resistor (4a), Al, which is an electric conductor, is vacuum-deposited to a thickness of 1.5 μm.

Again, by photo-etching, the input terminal (5)
Al is removed from portions other than (6) and the output terminal (7).

In the above configuration, the static characteristics to the magnetic field of the sensing resistor (3a) and the compensation resistor (4a), as shown in FIG. 2, respectively, the static characteristics R ₃ of the detection resistor with a low magnetic field (3a)
Is as shown more resistance change the smaller the static characteristics R ₄ of the compensating resistor (4a).

As shown in FIGS. 3 and 4, the above magnetic detecting element (1a) is incorporated in a proximity switch (10a) having the same configuration as that of the conventional example, except for the magnetic detecting element (1a). As shown in FIG. 5, when this proximity switch (10a) is mounted on the piston cylinder (21), the compensation resistor (4a) and the detection resistor (3a) change the output V of the differential amplifier (19). Fig. 8 (a) shows the output characteristics obtained by individually decomposing the effect on _A.
(B).

As shown in FIG. 7 (b), the output characteristic of the detection resistor (3a) is a circuit in which the compensation resistor (4a) is replaced with a resistor (4r) having the same resistance value as the compensation resistor (4a). (However, the temperature coefficient is ignored, and the measurement is performed under the condition of a constant temperature.) The output characteristic of the compensation resistor (4a) is also the same as shown in FIG. 7 (a). Was measured by a circuit in which a resistor (3r) having the same resistance value as the detection resistor (3a) was replaced.

As a result, as shown in FIG. 8 (b), the characteristic of the detection resistor (3a) has a broader peak at the center of the detection position O than the characteristic of the conventional magnetic sensing element (1) (FIG. 32 (b)). It has P ₁ ′ and an outer peak P ₃ ′.

As shown in FIG. 8 (a), the characteristic of the compensating resistor (4a) has a very small negative peak on both sides of the center of the detection position O.
P ₂ ′, and the output characteristics of the differential amplifier (19) are, as shown in FIG. 6 (a), the detection resistor (3a) and the compensation resistor (FIG. 8 (a), (b)). be a composite of characteristics of (4a), when one half of the peak P ₁ of the center of the detection position O of the output V _a of the threshold V _T of the differential amplifier (19) of the comparator (20), operating region L ₁ to the output V ₀ is on the comparator (20) is about 5mm as shown in FIG. 6 (b).

Next, a second embodiment of the present invention will be described with reference to FIGS.

The magnetic sensing element (1b) shown in FIG. 9 has the same detection resistors and compensation resistors (3b ₁ ) (4b ₁ ) and (3b ₂ ) (3b ₂ ) as those of the first embodiment on one substrate (2). 4b ₂ ) are formed by connecting two sets in parallel, the input terminals (5) and (6) are common, and the output terminals (7 ₁ ) and (7 ₂ ) are separately provided.

The strips (8 ₁ ) (8 ₂ ) of this magnetic sensing element (1b) are 16μ
It is set to a width W _A of m, the strip section (9 ₁₎ (9 ₂₎ the width of 8μm
Set to W _B.

The lengths l _A and l _{B of} these strips (8 ₁ ) (8 ₂ ) (8 ₁ ) (8 ₂ )
Are set so that the resistance values of the detection resistor (3b ₁ ) and the compensation resistor (4b ₁ ) and the resistance value of the detection resistor (3b ₂ ) and the compensation resistor (4b ₂ ) are substantially equal to each other. The strip portions (8 ₁ ) (8 ₂ ) (9 ₁ ) (9 ₂ ) are covered with a SiO protective film (27).

The input terminal (5) (6) and an output terminal (7 ₁₎
(7 ₂₎ is formed by Cu-Sn alloy.

The above magnetic sensing element (1b) includes a proximity switch (10b) as shown in FIG. 10 and a detection and compensation resistor (3b ₁ ).
(3b ₂ ), (4b ₁ ), and (4b ₂ ) are mounted face down on the circuit board (12) side. In FIG. 10, (11) is a signal processing circuit.

Circuit of the proximity switch (10b) is detecting resistors as shown in FIG. 11 and (3b ₁₎ and the compensation resistor coupling point (4b ₁₎ (output terminal) (7 _1), resistor (16 ₁₎ and Variable resistance (1
The connection point of 7 ₁ ) is input to the differential amplifier (19 ₁ ) to form a first bridge. Similarly, a detection resistor (3 b ₂ ), a compensation resistor (4 b ₂ ), a resistor (16 ₂ ), the variable resistor (17 ₂₎ and a differential amplifier (19 _2), the second bridge is configured, these bridges through the input terminal (5) (6) are both coupled to the power source E _0. The differential amplifier (1
9 ₁₎ (output V _A1, V _A2 19 _2), each output V _A1, V
It is input to the _A2 positive maximum 1 threshold comparator half of the peak _{P 1 (20 1) (20} 2). The output of these comparators _{(20 1) (20 2)} V0 1, V0 2 , on the one hand EOR
(ExclusiveOR) It is output as Vs through a circuit (29), and is output as Vc through an AND circuit (30).

FIGS. 12 (a) to 12 (f) show outputs of the respective elements when the proximity switch (10b) having the above configuration is attached to the piston cylinder (212) similar to the first embodiment.

As shown in FIGS. 12 (a) and 12 (b), the outputs _VA1 and _VA2 of the differential amplifiers (19 ₁ ) and (19 ₂ ) are as shown in FIGS. 12 (a) and 12 (b). ) is substantially the same as the output V _a of pitch (0 of the resistor (3b ₁₎ (4b ₁₎ and the resistor (3b ₂₎ (4b _2).
8mm), the center position is shifted to the left and right, and the comparators (20 ₁ ) (20 ₂ ) as shown in FIGS.
The outputs V ₀₁ and V ₀₂ are similarly shifted to be operating regions L ₂ and L _{3 of} about 4.6 mm, respectively.

Since the output Vc of the AND circuit (30) is the logical product of FIGS. 12 (c) and (d), as shown in FIG. the L _4.

Since the output Vs of the EOR circuit (29) is the exclusive OR of FIGS. 12 (c) and 12 (d), as shown in FIG.
Of 0.8mm on each side of the operating region L ₄ of the AND circuit (30) operating region L ₅
Is generated.

In the above configuration, the output Vc of the AND circuit (30) indicates that the piston (24) is within the range of operating region L ₄ of 3.8mm around the detection position O, the output Vs of the EOR circuit (29) Does not reach the working area L ₄ , but in the vicinity of the working area L ₄
A signal indicating that the range of the operating region L ₅ within 0.8 mm.

A third embodiment of the present invention will be described with reference to FIGS.

In FIG. 13, (1c) has a detection resistor (3c), a compensation resistor (4c), input terminals (5) (6) and an output terminal (7) formed on the surface of a glass substrate (2). It is a magnetic detection element.

The sensing resistor (3c) is a ferromagnetic magnetoresistive material
A plurality of strips (8J) and strips (8K) were formed in parallel with the Ni-Fe alloy, and the angle θ between these strips (8J) and strips (8K) was set to 60 °. The rectangular portions (8J) and (8K) are connected in series. Then, the strip (8) of this detection resistor (3c)
J) (8K) is set to 18μm in width W _A at a thickness of about 800 Å.

The compensating resistor (4c) connects a plurality of parallel strips (9) oriented in a direction perpendicular to the average direction of the strips (8J) and (8K) of the detection resistor (3c) in series. Are formed in a substantially rectangular shape as a whole. This strip (9) is made of Ni-Fe
An alloy, a thickness of about 800 Å, a width W _B of 6 [mu] m, and,
The resistance value of the compensating resistor (4c) and the sensing resistor (3c) is formed in a substantially equal length l _B, is smaller than the detection resistor this area (3c).

One end of the compensating resistor (4c) and one end of the detecting resistor (3c) are connected to each other, and the output terminal (7) is formed of an electric conductor to be connected to the connection point. . The input terminals (5) and (6) are formed of a good electrical conductor, and the detection resistor (3c) and the compensation resistor (4c)
Are respectively connected to the other ends of the.

In the above configuration, the static characteristics to the magnetic field of the sensing resistor (3c) and the compensation resistor (4c), the compensation resistance than static characteristics R ₃ each detection resistor in the low magnetic field as shown in FIG. 14 (3c) a indicates the resistance change the smaller the static characteristics R ₄ of the body (4c).

As shown in FIGS. 15 and 16, the above magnetic detecting element (1c) is incorporated in a proximity switch (10c) having the same configuration as that of the conventional example except for the magnetic detecting element (1c). This proximity switch (10c) is connected to the piston cylinder (2
The output characteristics obtained by separately decomposing the effects of the compensation resistor (4c) and the detection resistor (3c) on the output _VA of the differential amplifier (19) when attached to (1) are shown in FIGS. ). The output characteristic of the compensation resistor (4c) is substantially the same as that of the first embodiment shown in FIG. 7 (a), and the detection resistor (3c) is replaced by the detection resistor (3c).
The output characteristic of the detection resistor (3c) is measured by a circuit in which the resistor (3r) having the same resistance value is replaced.
In a manner similar to the first embodiment of FIG. 7B, the measurement was performed using a circuit in which the compensation resistor (4c) was replaced with a resistor (4r) having the same resistance value as the detection resistor (4c).

As a result, as shown in FIG. 17 (b), the characteristic of the detection resistor (3c) is slightly concave at the center of the detection position O, but the characteristic of the conventional magnetic detection element (1) (32). It has a thicker peak P ₁ ′ than FIG. Compensation resistor (4
The characteristic of c) has a very small negative peak P ₂ ′ on both sides of the center of the detection position O as shown in FIG. 17A, and the output characteristic of the differential amplifier (19) is as shown in FIG. As shown in (a),
Figure 17: (a) compensating resistors (b) (4c) and the detection resistor becomes a composite of characteristics of (3c), the comparator differential amplifier a threshold V _T of (20) (19) Assuming that the value P _{1 at} the center of the detection position O of the output _VA is ２, the operating area L ₆ where the output V ₀ of the comparator (20) is turned on is approximately as shown in FIG. 18 (b). 7 mm.

In Figure 13, the operating region L ₆ of the comparator (20) when the angle θ of the strip portion and (8 J) strip portion and (8K) was varied 1 ° to 90 DEG of the sensing resistor (3c) Table 1 below shows whether the device can be actually used.

When the angle θ becomes 80 ° or more in FIG. 13, the characteristic of the detection resistor (3c) shows a large decrease in the value P ₁ ′ at the center of the detection position O and a large peak on both sides as shown in FIG.
P ₄ ′, and the output characteristic of the differential amplifier (19), which is a combination of this characteristic and the characteristic of the compensation resistor (4c) shown in FIG. 17 (a), is shown in FIG. as shown in having two peaks P _4. Therefore, the difference 0V to be 1 to the reference potential of half the value P ₁ that is central to the detection position O of the output V _A of the differential amplifier (19) a threshold value V _T of the comparator (20) And the threshold value V _{T is set} to one half of the peak P ₄ , as shown in FIG.
0) output V ₀ is split into two is the operating region L ₆ 'turned on, the less likely it is possible to determine the detection position O.

Therefore, in the third embodiment of the present invention, the angle θ formed between the strip portion (8J) and the strip portion (8K) of the detection resistor (3c) is suitably in the range of 0 ° ≦ θ ≦ 75 °.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. 21 to 24.

The magnetic sensing element (1d) shown in FIG. 21 has an angle between a compensation resistor (4d) similar to the third embodiment and a plurality of strips (8) on a substrate (2). Is formed by connecting the detection resistor (3d) formed in a substantially fan shape as a whole,
An input terminal (5) (6) and an output terminal (7) are provided. The angle θ formed between the right end strip (8) and the left end strip (8) of the detection resistor (3d) is set to 90 °.

The strip (8) of the magnetic sensing element (1d) has a width of 16 μm.
To W _A, the strip section (9) is set to a width W _B of 6 [mu] m, these strip parts (8) (9) of length l _A, l _B detection resistor (3d) and the compensating resistor (4d) Are set to be substantially equal to each other, and the strip portions (8) and (9) are formed of the SiO protective film (2
7), and further covered with a moisture-proof film of epoxy resin (28).

The input terminals (5) and (6) and the output terminal (7)
It is formed of a Cu-Ni alloy.

As shown in FIG. 22, the magnetic detection element (1d) is connected to the proximity switch (10d) and the detection and compensation resistor (3d) (4
d) is mounted face down on the circuit board (12) side.

FIGS. 23 (a) and 23 (b) show the outputs when the proximity switch (10d) having the above configuration is attached to the same piston cylinder (21) as the first embodiment.

The output of the differential amplifier (19) is, as shown in FIG.
Has a thicker peak P _1, the output V ₀ which comparator (20)
There differential area L ₇ which is turned is about 6.5mm, as shown in Figure 23 (b).

In FIG. 21, the angle provided between the plurality of strips (8) of the detection resistor (3d) is changed, and the angle θ between the right end strip (8) and the left end strip (8) is set to one. ° 135 and differential area L ₇ of the comparator (20) when changing at DEG whether the actual use are shown in Table 2.

21 When the angle θ is equal to or greater than 130 ° in view, the characteristics of the sensing resistor (3d), as shown in FIG. 24, a large peak with the value P ₁ 'of the center of the detection position O drops significantly on either side P ₄ and it becomes difficult to determine the detection position O as in the third embodiment shown in FIGS. 20 (a) and 20 (b).

Therefore, in the fourth embodiment of the present invention, the right end strip (8) and the left end strip (8) of the detection resistor (3d).
Is appropriately in the range of 0 ° <θ ≦ 125 °.

In the above third and fourth embodiments, the glass substrate (2)
A pair of detecting and temperature compensating resistors (3c) (4c) or (3d) (4d) are formed on the top, but as in the second embodiment, two resistors are provided on one glass substrate. A pair of detecting and temperature compensating resistors (3c) (4c) or (3d) (4d) may be connected in parallel to form a common input terminal (5) (6).

In each of the above embodiments, the temperature compensation resistors (4a) (4b
₁ ) Although (4b ₂ ), (4c) and (4d) are substantially rectangular, the present invention is not limited to this. If the strips (9) are parallel, for example, a trapezoidal shape may be used. Good.

In each of the above embodiments, the glass substrate (2) is used as the insulating substrate. However, the present invention is not limited to this. For example, any insulating substrate such as a oxidized Si substrate may be used. I just need.

In each of the above embodiments, a Ni-Fe alloy was used as the ferromagnetic magneto-resistance material. However, the present invention is not limited to this. For example, a ferromagnetic magneto-resistance material such as a Ni-Co alloy may be used. Any material may be used.

In the above embodiment, an example was described in which the magnetic detection element was used as a proximity switch to detect the piston position of a piston cylinder. However, the present invention is not limited to this, and the resistance for detecting a ferromagnetic magnetoresistive material is not limited to this. Any magnetic sensing element having a body and a resistor for temperature compensation may be used.

[Effects of the Invention] Since the present invention is configured as described above, the resistor for temperature compensation and the resistor for magnetic detection are formed of the same ferromagnetic magnetoresistive material so that they can be formed in one process. Nevertheless, the influence of the magnetic field received by the temperature compensation resistor is reduced, and the range of the magnetic field received by the magnetic detection resistor is sufficiently widened. The present invention can provide a proximity switch having high reliability without any problem, and has an effect that mounting adjustment of the proximity switch becomes extremely easy.

[Brief description of the drawings]

1 to 8 show a first embodiment of the present invention. FIG. 1 is a plan view of a magnetic detecting element, and FIG. 2 is a detecting resistor and a compensating resistor of the magnetic detecting element of FIG. FIG. 3 is a plan view of a proximity switch in which the magnetic detection element of FIG. 1 is incorporated, and FIG.
FIG. 5 is a circuit diagram of the proximity switch shown in FIG. 5, FIG. 5 is a cross-sectional view showing an example in which the proximity switch shown in FIG. 3 is fixed to a piston cylinder, and FIG. 6A is an output characteristic of a differential amplifier of the proximity switch shown in FIG. FIG. 6 (b) is an output characteristic diagram of the comparator of the proximity switch of FIG. 3, FIG. 7 (a) is a circuit diagram of a circuit for obtaining characteristics of the compensation resistor, and FIG. 7 (b) is FIG. 8A is a circuit diagram of a circuit for obtaining the characteristics of the detection resistor, and FIG.
8 is an exploded output characteristic diagram of the compensating resistor of the magnetic sensing element shown in FIG.
FIG. 2B is an exploded output characteristic diagram of the detection resistor of the magnetic detection element of FIG. 9 to 12 show a second embodiment of the present invention. FIG. 9 is a plan view of a magnetic sensor, and FIG. 10 is a part of a proximity switch incorporating the magnetic sensor of FIG. FIG. 11 is a circuit diagram of the proximity switch of FIG. 10, and FIG.
12 (a) to 12 (f) are output characteristic diagrams of each element of the proximity switch of FIG. 13 to 20 show a third embodiment of the present invention. FIG. 13 is a plan view of a magnetic sensing element, and FIG. 14 is a detection resistor and a compensation resistor of the magnetic sensing element of FIG. FIG. 15 is a partially cutaway plan view of a proximity switch incorporating the magnetic sensing element of FIG. 13, FIG. 16 is a circuit diagram of the proximity switch of FIG. 15, and FIG. FIG. 17A is an exploded output characteristic diagram of the compensating resistor of the magnetic detecting element of FIG. 13, FIG. 17B is an exploded output characteristic diagram of the detecting resistor of the magnetic detecting element of FIG.
18 (a) is an output characteristic diagram of the differential amplifier of the proximity switch of FIG. 15, FIG. 18 (b) is an output characteristic diagram of the comparator of the proximity switch of FIG. 15, and FIG. 19 is θ = 80 ° 20 (a) is the output characteristic diagram of the differential amplifier when θ = 80 °, and FIG. 20 (b) is the output characteristic diagram of the comparator when θ = 80 °. It is an output characteristic diagram. 21 to 24 show a fourth embodiment of the present invention. FIG. 21 is a plan view of a magnetic sensing element, and FIG. 22 is a part of a proximity switch incorporating the magnetic sensing element of FIG. FIG. 23 (a) is an output characteristic diagram of the differential amplifier of the proximity switch of FIG. 22, FIG. 23 (b) is an output characteristic diagram of the comparator of the proximity switch of FIG. 22, and FIG. FIG. 24 is an exploded output characteristic diagram of the detection resistor when θ = 130 °. FIGS. 25 to 32 show a conventional example. FIG. 25 is a plan view of a conventional magnetic detecting element, and FIG. 26 is a partially cutaway view of a proximity switch incorporating the magnetic detecting element of FIG. 26 is a plan view, FIG. 27 is a circuit diagram of the proximity switch of FIG. 26, FIG. 28 is a cross-sectional view showing an example in which the proximity switch of FIG. 26 is fixed to a piston cylinder, and FIG. FIG. 29 (b) is an output characteristic diagram of the proximity switch comparator of FIG. 26, and FIG. 30 (a).
(B) is an explanatory diagram when the magnetic sensing element is placed in a magnetic field, FIG. 31 is a diagram showing the magneto-resistance change characteristics of the detecting resistor and the compensating resistor of the magnetic sensing element in FIG. 25, and FIG. (A) is the 25th
FIG. 32 is an exploded output characteristic diagram of the compensating resistor of the magnetic sensing element in FIG.
(B) is an exploded output characteristic diagram of the detection resistor of the magnetic detection element of FIG. (1a) (1b) (1c) (1d) ... magnetic detection element, (2) ...
... _{substrate, (3a) (3b 1)} (3b 2) (3c) (3d) resistor for ...... magnetic field _{detection, (4a) (4b 1)} (4b 2) (4c) (4d) ......
Resistor for temperature compensation, (5) (6) ... input terminal,
(7) (7 ₁₎ (7 ₂₎ ... output terminal, (8) (8 ₁₎ (8 ₂₎
(8J) (8K) (9) (9 ₁ ) (9 ₁ ) ... Strip section, (10a)
(10b) (10c) (10d) ... proximity switch, (11) ...
Signal processing circuit, (12) ... circuit board, (13) ... housing,
(14) ... I / O signal cable, (15) ... gold wire, (1
6) (16 ₁₎ (16 ₂₎ ...... resistance, (17) (17 ₁₎ (17 ₂₎ ...
... variable resistance, (19) (19 ₁₎ (19 ₂₎ ...... differential amplifier,
(20) (20 ₁₎ (20 ₂₎ ...... comparator (21) .... small piston cylinder, (22) ... cylinder, (23) ....
Band, (24) ... Piston, (25) ... Magnet, (26)
…… Rod, (27) …… Protective film, (28) …… Moisture proof film,
(29) EOR (ExclusiveOR) circuit, (30) AND circuit.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoshihiko Okawara, 364-1 Miyamoto, Ryuyo-cho, Iwata-gun, Shizuoka Prefecture Inside the Ryuyo Plant of Hamamatsu Electric Co., Ltd. (72) Inventor Juichi Koike 364-1, Miyamoto, Ryuyo-cho, Iwata-gun, Shizuoka Prefecture Hamamatsu Photoelectric Inside the Ryuyo Plant Co., Ltd. (72) Inventor Masanori Kashiuchi, 364-1 Miyamoto, Ryuyo-cho, Iwata-gun, Shizuoka Prefecture Inside the Ryuyo Plant Co., Ltd. (72) Kosuke Matsuura 364-1 Miyamoto, Ryuyo-cho, Iwata-gun, Shizuoka Prefecture Hamamatsu Photoelectric Co., Ltd. (72) Inventor Katsuhiro Kawai 364-1 Miyamoto, Ryuyo-cho, Iwata-gun, Shizuoka Prefecture Hamamatsu Photoelectricity Co., Ltd. (72) Inventor Shinichi Suzuki 364-1 Miyamoto, Ryuyo-cho, Iwata-gun, Shizuoka Prefecture Hamamatsu Photoelectric Co., Ltd. Inside the factory (72) Inventor Tetsuo Sakuragi 364-1 Miyamoto, Ryuyo-cho, Iwata-gun, Shizuoka Prefecture Inside the Ryuyo factory of Hamamatsu Koden Co., Ltd. (56) References JP-A-2-300681 (JP, A) JP-A-57-83074 (JP, A) JP-A-57-80578 (JP, A) JP-A-57-80579 (JP, A) JP-A-57-98103 (JP, A) JP-A-52-33508 (JP, A) JP-A-48-71893 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01R 33/00-33/18

Claims (3)

(57) [Claims] A plurality of elongated strips serving as a current path are folded back by a ferromagnetic magneto-resistive material, and these strips are connected in series to each other for magnetic detection and temperature compensation. It is formed on an insulating substrate so that the resistance values in the state are substantially equal, and the average directions of the currents flowing through the respective strips constituting these magnetic detection and temperature compensation resistors are substantially perpendicular to each other. In the magnetic detection element, these magnetic detection and temperature compensation resistors are connected in series, and the approach of magnetism is detected by a change in electric resistance of the magnetic detection resistor due to a magnetoelectric resistance effect. The resistor for temperature compensation is formed such that the width of the strip is narrower than the width of the strip of the resistor for detection. Smaller than body A magnetic sensing element, which is characterized in that the magnetic sensing element is formed. 2. A plurality of elongated strips serving as current paths made of a ferromagnetic magneto-resistive material are folded back, and these strips are connected in series to each other for magnetic detection and temperature compensation. It is formed on an insulating substrate so that the resistance values in the state are substantially equal, and the average directions of the currents flowing through the respective strips constituting these magnetic detection and temperature compensation resistors are substantially perpendicular to each other. In the magnetic detection element, these magnetic detection and temperature compensation resistors are connected in series, and the approach of magnetism is detected by a change in electric resistance of the magnetic detection resistor due to a magnetoelectric resistance effect. The angle θ between the strips on both sides of the magnetic detection resistor
Is 0 ° <θ ≦ 75 °, and the strip portions on one side are arranged in a C-shape formed in parallel with each other, so that the electric resistance change due to the magnetoelectric resistance effect due to the approach of magnetism is used for the temperature compensation. A magnetic sensing element characterized by being made larger than the resistor. 3. A plurality of elongated strips serving as current paths made of a ferromagnetic magneto-resistive material are folded back, and these strips are connected in series to each other for magnetic detection and temperature compensation. It is formed on an insulating substrate so that the resistance values in the state are substantially equal, and the average directions of the currents flowing through the respective strips constituting these magnetic detection and temperature compensation resistors are substantially perpendicular to each other. In the magnetic detection element, these magnetic detection and temperature compensation resistors are connected in series, and the approach of magnetism is detected by a change in electric resistance of the magnetic detection resistor due to a magnetoelectric resistance effect. The angle θ between the strips at both ends of the resistor for magnetic detection
Is arranged in a substantially fan shape within a range of 0 ° <θ ≦ 125 °, whereby a change in electric resistance due to a magnetoelectric resistance effect due to approach of magnetism is made larger than that of the temperature compensating resistor. Detection element.