JPH0643254A - Lengthy magnetic sensor - Google Patents

Abstract

PURPOSE:To surely detect a specimen even when its length and position are changed, increase the output signal even for a short specimen, and judge the passing position by guiding output lead wires from multiple magnetic resistance elements arranged above a lengthy magnet. CONSTITUTION:Magnetic resistance elements 11, 12; 21, 22; 31, 32; 41, 42 are proximately arranged in pairs respectively above a lengthy magnetic bias magnet 5, and the magnetic resistance elements are connected to a power lead wire Vin and a ground lead wire GND in parallel. Output lead wires OUT1-4 are guided respectively from the magnetic resistance elements arranged in pairs. When a lengthy specimen L passes, output signals Ls1-4 are obtained from the lead wires OUT1-4. When a short specimen S passes, an output signal Ss3 is obtained from the lead wire OUT3 respectively, and both the lengthy and short specimens are detected. Even when the position of the specimen S is changed, it can be largely detected like the output signal Ss3 within the range of the elements 11-41, and the passing position of the specimen S can be judged based on the output signal from any output lead wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long magnetic sensor, and more particularly to a long magnetic sensor which is excellent in detection ability and capable of discriminating a passing position of a subject.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory view of an example of a conventional long magnetic sensor. In this long magnetic sensor 300, long magnetic resistance elements 301 and 302 are installed above the long magnetic bias magnet 5, and a power supply lead Vin, a ground lead GND, and an output lead OUT are derived. Is configured. An output signal Ls is obtained by passing through the long subject L. In addition, the output signal S
s is obtained.

That is, the long magnetoresistive elements 301, 3
Since 02 is used, both a long subject L and a short subject S can be detected. Further, the magnetic resistance elements 301, 3
Within the range of 02, even if the position of the short subject S changes, it can be detected.

[0004]

In the conventional long magnetic sensor 300, the long magnetic resistance elements 301 and 302 are used.
Therefore, even if the length or position of the subject is changed, it can be reliably detected. However, the output signal Ls and the output signal Ss
As can be seen by comparing the above, there is a problem that the output signal becomes smaller as the subject becomes shorter. Further, there is a problem that it cannot be determined which position the subject has passed.
Therefore, an object of the present invention is to reliably detect even if the length or position of the subject changes, and to obtain a large output signal even when the subject becomes short. An object is to provide a long magnetic sensor capable of discriminating whether or not the vehicle has passed through.

[0005]

In the long magnetic sensor of the present invention, a plurality of magnetoresistive elements are arranged above a long magnet without a gap or at a predetermined gap, and each magnetoresistive element is arranged. It is a feature of the construction that the output lead wire is derived from the above. In the above structure, each magnetoresistive element is
It is preferable to use a terminal type and to make it possible to adjust the length of the detection unit by external connection.

[0006]

In the long magnetic sensor of the present invention, a plurality of magnetoresistive elements are arranged above the long magnet without a gap or at a predetermined gap, and an output lead wire is led out from each magnetoresistive element. Since the length is long as a whole, it is possible to reliably detect even if the length or position of the subject changes. On the other hand, since the output signal of each magnetoresistive element can be obtained independently, it is possible to obtain a large output signal even when the subject is short,
It is also possible to determine which position the subject has passed through.

[0007]

The present invention will be described in more detail with reference to the embodiments shown in the drawings. The present invention is not limited to this. FIG. 1 is an explanatory diagram of a long magnetic sensor according to an embodiment of the present invention. This long type magnetic sensor 1
Reference numeral 00 indicates the magnetic resistance elements 11 and 12, the magnetic resistance elements 21 and 22, the magnetic resistance elements 31 and 32, and the magnetic resistance elements 41 and 42 close to each other above the long magnetic bias magnet 5. Arranged, each pair of magnetoresistive elements is connected in parallel to the power lead wire Vin and the ground lead wire GND, and the output lead wires OUT1, OUT2, OUT3, OUT4 are derived from each pair of magnetoresistive elements. Has been done.

By passing the long object L, output signals Ls1, Ls are output from the output lead wires OUT1, OUT2, OUT3, OUT4.
2, Ls3, Ls4 are obtained. Also, in the example of FIG.
The output signal Ss3 is obtained from the output lead wire OUT3 by passing through the short length of the subject S.

That is, both the long specimen L and the short specimen S can be detected. In addition, the magnetoresistive elements 11 and 12
Within the range from to the magnetoresistive elements 41 and 42, even if the position of the short subject S varies, it can be detected. Moreover,
Even a short subject S can obtain a large output signal Ss3. Further, depending on which output lead wire the output signal is obtained from, it is possible to determine which position the subject S has passed through.

FIG. 2 is an explanatory view of a long magnetic sensor according to another embodiment of the present invention. This long magnetic sensor 200
Is arranged above the long magnetic bias magnet 5 in the proximity of the magnetic resistance elements 11 and 12, the magnetic resistance elements 21 and 22, the magnetic resistance elements 31 and 32, and the magnetic resistance elements 41 and 42. Then, lead wires of four terminals are led out from each pair of magnetoresistive elements. This long magnetic sensor 200
According to this, the detection range can be easily changed by externally connecting the lead wires of four terminals from each pair of magnetoresistive elements.

In the example shown in FIG. 2, in order to match the detection range to the medium-sized subject M and the short-sized subject S, external connection is used to connect the magnetoresistive elements 11 and 12 and the magnetoresistive elements 21 and 2.
2 and the magnetoresistive elements 31 and 32 are connected in series to be integrated, the power supply lead Vin and the ground lead GND are connected, and one output lead OUT1 is taken out. Further, with respect to the magnetoresistive elements 41 and 42, the power source lead wire V
In is connected to the ground lead wire GND and one output lead wire OUT2 is taken out.

[0012]

According to the long magnetic sensor of the present invention,
Even if the length or position of the subject changes, it can be reliably detected. Further, it is possible to obtain a large output signal even if the subject becomes short. Further, it is possible to determine which position the subject has passed through.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a long magnetic sensor according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a long magnetic sensor according to another embodiment of the present invention.

FIG. 3 is an explanatory diagram of an example of a conventional long magnetic sensor.

[Explanation of symbols]

100,200 Long type magnetic sensor 5 Magnets for magnetic bias 11, 12, 21, 22, 31, 32, 41, 42
Magnetoresistive element OUT1, OUT2, OUT3, OUT4
Output lead wire L, S, M

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 43/08 U 9274-4M

Claims (2)

[Claims] 1. A long magnet characterized in that a plurality of magnetoresistive elements are arranged above a long magnet without a space or at a predetermined space, and an output lead wire is led out from each of the magnetoresistive elements. Type magnetic sensor. 2. The long magnetic sensor according to claim 1, wherein each magnetoresistive element is a four-terminal type, and the length of the detection unit can be adjusted by external connection. Type magnetic sensor.