JPS61172079A - Hall sensor - Google Patents

Abstract

PURPOSE:To make it possible to alter sensitivity to a large extent from high sensitivity to low one without using a yoke having a complicated shape, by arranging a bias magnet to a Hall IC having a Hall element mounted therein in the side opposite to the magnetic detection surface of said IC. CONSTITUTION:A bias permanent magnet 7 is arranged to a Hall IC3 having a Hall element mounted therein in the side opposite to the magnetic detection surface 5 of said IC3. When the magnetic pole of the bias permanent magnet 7 in the side of the Hall IC3 is set to the same magnetic pole (N-pole) as the detection magnetic pole (N-pole) of a detection permanent magnet 6, the magnetic flux by the bias permanent magnet 7 takes a direction reverse to the operation magnetic flux of the hole IC3 and the Hall element can be adjusted to low sensitivity. When the magnetic pole of the bias permanent magnet 7 opposed to the Hall IC3 is set to a magnetic pole (S-pole) different from the detection magnetic pole (N-pole), the magnetic flux by the bias permanent magnet 7 comes to the same direction as the operation magnetic flux of the Hall IC3 and the Hall element can be adjusted to high sensitivity. As mentioned above, only by changing the magnetic pole directed to the side of the Hall IC3 of the bias permanent magnet 7, sensitivity can be altered to a large extent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a Hall sensor used in a magnetic proximity switch that turns on when detecting magnetism. .

[Background technology]

As shown in Fig. 1, a conventional Hall sensor of this type includes a dot-shaped Hall element arranged on a substrate +1), and an FrW4 Hall IC (31) containing a built-in (2) housed in a case (4). Or, as shown in Figure 2, Hall IC (
There are devices that increase sensitivity by arranging a substantially U-shaped yoke (5) inside the case (4) so that a portion of the magnetic detection surface (5) in 3) comes into contact with the 0 surface opposite to the magnetic detection surface (5). However, with the above configuration, it is impossible to significantly increase or decrease the sensitivity, and even if a yoke (5) as shown in Figure 2 is used, the sensitivity will be significantly Changes were impossible. Note that (6) in the figure is a permanent magnet for detection.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a structure that can easily achieve very high sensitivity or very low sensitivity without using a yoke with a complicated shape. The present invention provides a Hall sensor having the following characteristics.

[Disclosure of the invention]

(Example 1) Figure 3 shows the configuration of Example 1. This example is for lowering the sensitivity, and the bias permanent magnet (7) is placed opposite the magnetic detection surface (4) of the Hall ICt3). The magnetic pole of the bias permanent magnet (7) on the side of the Hall IC (31 side) is the detection magnetic pole (for example, N pole) of the detection permanent magnet (6).
The same magnetic pole is used.

At the center of the Hall IC (31), as shown in Figure 4, the magnetic flux due to the bias permanent magnet (7) flows as indicated by the dashed arrow, and is in the opposite direction to the operating magnetic flux of the Hall IC!31. For this reason, the operation Gauss of the Hall IC [3] is controlled by the a1 bias permanent magnet (7).
) If the magnetic flux at the center is b, a magnetic flux density of a+b is required by the detection permanent magnet (6). This is due to the low sensitivity of the tabs.

(Example 2) FIG. 5 shows this example. In this example, the magnetic pole opposite to the Hall IC (31) of the bias permanent magnet (7) is detected as a magnetic pole different from the magnetic pole (for example, N pole), This is the S pole.

In this embodiment, however, the magnetic flux generated by the bias permanent magnet (7) flows as shown by the broken line arrow in FIG. 6, and is in the same direction as the operating magnetic flux of the Hall IC (3).

For this reason, if the operating Gauss of the Hall IC+31 is a1, and the magnetic flux at the center of the Hall IC+31 due to the bias permanent magnet (7) is b, then the operation can be made by simply supplying the magnetic flux density of a-b using the detection permanent magnet (6). become. In other words, it has high sensitivity.

(Example 3) This example uses a plurality of permanent magnets (7a
), (7b) are stacked to form a bias magnet (7)', depending on the number of magnets! It is possible to adjust 1lI8 degrees.

Permanent magnets (7), (7a), (7b) used in each example
) Various types of magnets such as ferrite magnets and rubber magnets can be used.

〔Effect of the invention〕

Final F! In A, the bias magnet is placed on the opposite side of the magnetic detection surface of the Hall IC with a built-in Hall element, so just by adjusting the magnetic pole of the bias magnet facing the Hall IC side, the sensitivity can be set to high or low. The sensitivity can be changed significantly, and there is no need for a 3-couple having a complicated shape.

[Brief explanation of drawings]

1 and 2 are sectional views of the conventional example, FIG. 3 is a sectional view of Embodiment 1 of the present invention, and 47J4 is an explanatory diagram of the same operation,
FIG. 5 is a sectional view of Embodiment 2 of the present invention, FIG. 6 is an explanatory diagram of the same operation as above, and FIG. 7 is a sectional view of Embodiment 3 of the present invention.
(21 & 1 Hall element, (3) is a Hall IC, +51 is a magnetic detection surface, +7), (7a), (7b) are permanent magnets for bias. Agent Patent Attorney Ishi 1) Chief 7 @ Figure 1 Figure 2 Procedural Amendment (Voluntary) 1. Display of the case 1983 Patent Application No. 497402, name of the invention Hall sensor 3, person making the amendment Relationship to the case Patent applicant address 1048 Kadoma, Kadoma City, Osaka Prefecture Name (583) Matsushita Electric Works Co., Ltd. Representative Iku Kobayashi 4, Agent 5, Date of amendment order Voluntary 6, Number of inventions to be increased by amendment Application number: Japanese Patent Application No. 59-49740 No. 1, page 2, line 8 of the specification of the present application; In line 12, “Yoke (
5)" are respectively corrected as "Yoke (8)". 2. "Magnetic detection surface (4)" on page 3, line 5 of the same as above is corrected to "magnetic detection surface (May)." 3. After "Naru no deru" on page 4, line 9 of the same as above, the following is written: Insert the following sentence. ``However, choose a magnet so that a>b, because if a exceeds b, it will be in the operating state at the initial stage.'' 4. Figures 1 and 2 in the drawings. , Figure 4 is corrected as shown in the attached sheet.

Claims (3)

[Claims] (1) A Hall sensor characterized in that a bias magnet is disposed on the side opposite to the magnetic detection surface of a Hall IC with a built-in Hall element. (2) The Hall sensor according to claim 1, further comprising a bias magnet with the same magnetic pole as the detection magnetic pole of the Hall IC facing toward the Hall IC. (3) Connect the magnetic pole different from the detection magnetic pole of the Hall IC to the Hall IC.
The Hall sensor according to claim 1, further comprising a bias magnet directed toward the side.