JPH02120616A - Magnetic displacement detector - Google Patents

Abstract

PURPOSE:To always detect minute displacement quantity by mounting a plurality of diamagnetic bodies between a pair of magnets opposed to each other so as to differentiate magnetic poles and generating relative displacement in accordance with the displacement of an object to be detected and detecting displacement quantity on the basis of a change of magnetic flux. CONSTITUTION:A pair of magnets 1, 2 opposed so as to differentiate magnetic poles are mounted so as to be relatively replaced each other with the displacement of an object to be detected and, when the diamagnetic bodies 3 mounted to the magnets 1, 2 are overlapped with each other, the magnetic flux between the magnets 1, 2 is generated only in a region where the diamagnetic bodies 3 are absent by the diamagnetic action of each of the diamagnetic bodies 3 and detected by a Hall element 4 to input the output voltage corresponding to the magnetic flux to a displacement quantity calculation circuit 5 and the relative displacement quantity of the magnets 1, 2 is detected. As mentioned above, since displacement quantity is led out by grasping the displacement of magnetic flux, minute displacement quantity can be detected with the reduction of the pattern widths of the diamagnetic bodies 3 without receiving the effect of dust or contamination.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a magnetic displacement detection device.

(Prior Art) Optical displacement detection devices are widely used as displacement detection devices. This optical displacement detection device has the following features:
As shown in Publication No. 3120, a main scale and a vernier scale with slightly different pitch intervals are used as position detection scales, and by detecting the coincident point of both scale graduations, the position can be determined with the resolution of the difference in pitch interval of both scales. Although there are devices that improve position detection accuracy, optical displacement detection devices basically consist of one light-emitting element, an optical pattern for detecting displacement such as a lattice-like transmission pattern or a reflection pattern, and a light receiving device. elements, etc. are required.

Recently, it has become possible to make the optical pattern considerably smaller using thin film technology, and with this, it has become possible to detect minutely displaced liquids with optical displacement detection devices as well. It has become.

(Problem to be Solved by the Invention) However, on the other hand, if the optical pattern is contaminated with dust, dirt, etc. and the light is blocked, the resolution decreases due to the stain, etc. There was a risk that detection would become impossible.

In addition, in the optical displacement detection device, although the optical pattern can be made quite small, it is limited by the wavelength of light, and there is a limit to the detection of minute displacement amounts.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to enable detection of extremely small amounts of displacement at all times.

(Means and operations for solving the problem) In order to achieve this object, the present invention includes a pair of magnets that are opposed to each other with different magnetic poles and that are relatively displaced in accordance with the displacement of the detection target; a plurality of diamagnetic bodies provided between the pair of magnets and attached to one of the pair of magnets at regular intervals in the relative displacement direction; and a plurality of diamagnetic substances provided between the pair of magnets and attached to the other of the pair of magnets. A magnetic displacement detection device comprising: magnetic detection means according to the present invention.

- With the configuration described above, even when multiple diamagnetic materials are arranged at extremely small intervals using existing thin film technology,
By relatively displacing a pair of magnets, the magnetic flux detected by the magnetic detection means can be changed according to the arrangement 11 of the magnetic bodies by utilizing the diamagnetic action of the diamagnetic body, and the magnetic flux can be changed according to the magnetic flux change. Based on this, even extremely small displacement needles can be detected.

In addition, in order to detect magnetic flux, even if the pattern made of diamagnetic material etc. of magnet 1 is dirty, the magnetic flux will be detected.
It is not affected by dirt, etc., and the resolution does not deteriorate.

Therefore, it is possible to constantly detect extremely small displacements ψ using the −I− double weak terms.

(Example) Hereinafter, embodiments of the present invention will be explained based on the drawings.

In FIGS. 1 to 3, l is a pair of magnets 1 and 2 made of, for example, barium ferrite, and a pair of magnets l and 2 are attached to a detection target (not shown) and mutually move with the displacement of the detection target. A number of phrases can be used as appropriate to indicate relative displacement. The pair of magnets 1.2 are spaced at a predetermined distance (for example, 5m).
m), and one magnet 1 has its south pole face 1a facing the other magnet 2, and the other magnet 2 has its north pole face 2a facing It is pointing towards magnet 1 on the other hand.

A plurality of diamagnetic bodies 3 are attached to the S-pole surface 1a of the one magnet 1. The plurality of diamagnetic bodies 3 are arranged at regular intervals in the relative displacement direction (left and right direction in FIGS. 1 and 2), and the interval width (pitch) is, for example, 10 gm width. It will be done. The diamagnetic material may be, for example, a polycrystalline YBCO superconducting material as a completely diamagnetic material.

A diamagnetic material 3 is also provided on the N-pole surface 2a of the other magnet 2, similarly to the one magnet 1. To attach the diamagnetic material 3, the diamagnetic material 3 is sputter-formed, and then a certain width 1, for example 1
This is done by forming a miniaturized pattern with a width of 0 gm. Since these techniques are known as thin film techniques, their explanations will be omitted.

A plate-shaped Hall element 4 serving as magnetic detection means is provided between the pair of magnets 1.2. This Hall element 24 is sunk between a pair of magnets 1.2, and as shown in FIG. The diamagnetic material 3 is attached to the other magnet 2 so as to straddle the space between the diamagnetic material 3 and the adjacent diamagnetic material 3. This Hall element 4 has a function of outputting an output voltage according to the detected magnetic flux (magnetic field strength).

The output voltage of this Hall element 4 is input to a displacement I calculation circuit 5. This displacement rUB calculation circuit 5
A known value is used for the change 11 (the calculation circuit 5 calculates the displacement 1 of the detection target based on the output voltage from the Hall element 4).
It has a function of calculating i1-.

Therefore, according to the above configuration, as shown in FIG. Due to the diamagnetic effect, the magnetic flux (indicated by the arrow) between the magnets 1 and 2 is generated only in the region where the diamagnetic material 3 is not present. The Hall element 4 will detect this magnetic flux, and the Hall element 4 will output an output voltage according to the magnetic flux. In this case, the magnetic flux (output voltage of the Hall element) detected by the Hall element 4 takes the largest value (peak) as shown in FIG.

When a relative displacement occurs between the magnets 1 and 2 from the above state, for example, when the pattern width of the diamagnetic material 3 deviates, the magnetic flux is curved due to the diamagnetic action of the diamagnetic material, as shown in Figure 2. Therefore, the magnetic flux detected by the Hall element 4 is reduced to the minimum compared to the above state.

Therefore, the magnetic flux with respect to the amount of displacement shows the smallest value (trough) in FIG. 3.

In this way, even if the pattern of the diamagnetic material 3 on the magnets 1 and 2 is miniaturized, the magnetic flux detected by the Hall element 4 due to the relative displacement of both magnets 1 and 2 is as shown in Fig. 3. The voltage will change as shown, and the output voltage of the Hall element 4 will also change in the same way.

After this 1. The output voltage described above is input to a displacement calculation circuit, where the peaks and valleys of the output voltage (or detected magnetic flux) are counted, and based on this, the relative displacement of both magnets 1 and 2 is calculated.

In this way, since the amount of displacement is derived by capturing changes in magnetic flux, it is not affected by dust, dirt, etc. Moreover, if the pattern width is, for example, 10gm, the amount of displacement is calculated by 10ILm.
The amount of displacement can be determined with a resolution of , and as the pattern width of the diamagnetic material 3 becomes smaller, it becomes possible to detect minute amounts of displacement.

FIG. 4 shows another embodiment. In this embodiment, the same components as those in the previous embodiment are given the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, a superconducting material 6 is used in a plate-shaped Hall element 4 to increase detection sensitivity.

That is, a YBCO-based superconducting material 6 is sputter-formed on the upper and lower surfaces of the Hall element 4, and a film of, for example, lOJLm is formed at the same position on the upper and lower surfaces.
A hole 7 of the same diameter is formed by the phosphorography method. On this occasion,
The hole 7 is made into a tapered shape by taper etching (etching liquid H20) or lift-off method.

As a result, if the larger diameter is rQ and the smaller diameter is r, the magnetic flux detected by the Hall element 4 will be amplified to (ro/r)2, making it possible to detect with high sensitivity even in a small magnetic field region. Become.

(Effects of the Invention) As described above, the present invention can constantly detect extremely small amounts of displacement.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram for explaining one embodiment of the present invention, Fig. 2 is an operating state diagram of Fig. 1, Fig. 3 is a characteristic diagram showing a magnetic flux-displacement characteristic curve, and Fig. 4 is another embodiment. It is an enlarged explanatory diagram explaining an example. l, 2: Magnet la: S pole face 2a: N pole face 3: Diamagnetic material 4: Hall element

Claims (1)

[Claims] (1) A pair of magnets that face each other with different magnetic poles and are relatively displaced in accordance with the displacement of the object to be detected, and a pair of magnets provided between the pair of magnets and arranged at equal intervals in the relative displacement direction on one of the pair of magnets. A magnetic displacement detection device comprising: a plurality of diamagnetic bodies attached to the magnet; and magnetic detection means provided between the pair of magnets and attached to the other of the pair of magnets.