JPS6079281A - Magnetic sensor - Google Patents

Abstract

PURPOSE:To elevate the stability, reliability and sensitivity characteristic of a magnetosensitive element by a method wherein the element is sealed in the shape of a flat plate with a non-magnetic resin member and molded and additionally, a magnetic resin member is molded while pinching the member from both the surface and back thereof. CONSTITUTION:A hall element chip 21 is sealed by a resin made of a non-magnetic material, for example, an epoxy resin 28 together with a bonding wire 23 or the like, and the resin 28 is molded in a flat plate. Additionally, the resin 28 is made concave inward on both the surface and back thereof at the center thereof, namely the portion corresponding to the hall element chip 21, so that the thickness of the portion is thinner than other portions in the molding. A resin 29 made of a magnetic material, such as epoxy resin, mixed with fine particles of material with a high magnetic permeability such as Fe fine particles in the Fe- Ni system and Fe-Zn system is provided on both the surface and back of the resin 28. The resin 29 is molded sandwiching the resin 28 from the surface and back thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a magnetic sensor such as a Hall element having high sensitivity.

[Technical background of the invention]

A Hall element is a typical example of a magnetically sensitive element that converts magnetic force into an electric signal. The output voltage of this Hall element is measured by a circuit as shown in FIG. Ball element 1
o has two orthogonal sides as shown in the figure, and both sides of the − side <, , +: 3, t, 5J have a predetermined angle l#, @flow I
−i, and generates and outputs a voltage proportional to the magnitude of the applied magnetic flux density at that time between both sides 9i^1 of the other side, and this output voltage is measured after being amplified by amplifier 1.
, i lift 1. 1. Now, 8- in Hall element IO
Yaria's Futai I'l history is μ, 11f of Hall element 10
b 71j current l21; l: The value of the DC current I is IC
1. If the value of the human force iA resistance, which is the impedance of the Hall element 10 of I61 through which the above current flows, is Rd, and the applied magnetic flux density is B, then the pressure VH at the output of the Hall element 10 and the relationship between these values are as follows. A proportional relationship holds true.

VHCX:μ・ENG.・Rd-B・・・・・・・・・
(1) As is clear from the above formula (1), I, , r
If td is constant, the values of mobility μ and magnetic flux density B are large (゛-high output can be obtained. Therefore, in the past, indium antimony (I
The Hall element 10 is constructed using a material such as nSb) or gallium arsenide (GaAs).

[Highlights of background technology]

In conventional Hall elements using indium antimony, it is difficult to make a single crystal, so a thin film must be used, which has the disadvantage of lower element stability and reliability.

On the other hand, devices using gallium arsenide can make single crystals relatively easily and can improve device stability and reliability, but on the other hand, the value of μ is small, less than 1/1 of that using indium antimony. Therefore, high output cannot be obtained and high sensitivity cannot be easily achieved.

As described above, there is no conventional Hall element that satisfies both element stability and reliability as well as high sensitivity characteristics at the same time, and the reality is that one of them comes at the expense of the other.

[Object of the Invention] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to simultaneously satisfy element stability and reliability and high sensitivity characteristics. It's about doing.

[Summary of the invention]

In the magnetic sensor according to the present invention, a magneto-sensitive element is first molded into a flat plate shape with a magnetic resin member, and then this non-magnetic resin member is sandwiched between both sides of the non-magnetic resin member in a -lJ° sandwich shape. By molding the magnetic resin part, we have achieved a total magnetic collection effect and a high +iC'T degree, making it possible to achieve magnetic sensitivity using gallium arsenide and the sensitivity of I4. It is.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a perspective view showing the entire external appearance of the <a-senna gold Hall element according to the present invention, and FIG. 3 is a sectional view thereof. In Igl, 21 is a Hall element in which an insulating substrate made of gallium arsenide is used, and silicon ions are selectively implanted into the surface region of the substrate to form an n-type region as shown in FIG. It's a chip. This chip 21 is fixed onto support leads 22 using solder or adhesive. Further, on the surface of the Hall element chip 2, two input electrodes for supplying the entire operating current as described above and two output electrodes for guiding the output '[IL pressure to the outside] are provided. The 'magnetic poles on the surface of these dusts 20 are connected to the four external leads 24 to 2 through the bonding wire 23 made of gold (1 wire).
7 is connected. In addition, the Hall element Chinon o21 is the same as the above yJ! f'', (with blow wire 23, etc., non-magnetic resin/C, for example, engineering/j? ginseng resin 2
8, and this resin 28 is molded into a flat plate shape as shown in the figure. As shown in the figure, the resin 28 here is shaped like an inward concave part on both the front and back surfaces at the middle heat part, i.e., the 7445th position corresponding to the Hall element chip 2, and the thickness of this part is thicker than the other parts. Molded thinly. .

Both the front and back surfaces of the resin 28 are made of magnetic resin, such as Kogetsu? F e -N i type and "5-Z n
The resin 29 mixed with abrasive particles of a material with high magnetic permeability such as Fe fine particles is not provided, and therefore, the resin 29 holds the resin 28 on both its front and back surfaces in a "nandwich" manner. It is molded to look like this.

Hall event child C [, outside 1I11j with such a configuration
Since the resin 29 is a magnetic material, when placed in a magnetic field, magnetic flux is sufficiently collected and the electromagnetic effect can be enhanced. As a result of this /ζ, the 1 market flux density in the above formula (1) is increased, and thereby a high sensitivity) W degree can be achieved. It should be noted that the Hall element chip 21 is first formed using a non-magnetic resin 28, and a magnetic resin 29 is further formed on both sides of the pole element chip 7 made of gallium arsenide. '21 is originally a non-magnetic material, and if it is sealed and molded with a resin with a general sound f social body, the magnetic flux will pass through the resin part instead of passing through the chip '21 'i', )S. Furthermore, according to the above embodiment, the thickness of the non-magnetic tree 11128 corresponds to the chip 21 and is formed so that it becomes thinner at the groin part, so that the magnetic resistance at this part is reduced. is the smallest. Therefore,
i1.] 11.

FIG. 4 is a characteristic diagram comparing the positive characteristics of the outputs of the Hall element according to the above embodiment and the conventional one. As shown in the figure, the embodiment of the present invention shown by Izumi A has a larger output acid at the same if flux density of 1 tree than the conventional one shown by 11'1 line B. It can be seen that the pressure VH is broken.

〔Effect of the invention〕

As described above, in the magnetic range QJ according to the present invention, the magnetic sensing element was sealed in a flat plate shape with a non-magnetic resin material, and the non-magnetic resin material was further demonstrated. 8. A magnetic resin member is molded so as to be held between both sides of the dowel. For this reason, the magnetism collecting effect is sieved, and it is not possible to increase the density of magnetism, and although the stability and reliability of elements such as magneto-sensitive elements using a magneto-sensitive element using a magnetized aluminum alloy are high, it is difficult to obtain high usability. IJ1. proposes a magnetic sensor that can easily achieve high sensitivity even for objects, thereby satisfying element stability and reliability as well as inertia sensitivity characteristics at the same time. can. + ', (:
The magnetic sensing element may be made of materials other than gallium arsenide.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a circuit for measuring the output voltage of a Hall element, Fig. 2 is a perspective view of a Hall element according to an embodiment of the present invention, and Fig. 3 is a diagram showing its IIJ? -1/I 1, ζB4 diagram shows the output of the Hall element of the same embodiment and the conventional one! It is a figure showing I' nature. 2)...Hall element chip 9.22...time lead ゝ, 23...J? Endingwaya, 24-27・-
・External lead, 28...work, +5 cylindrical resin (non-magnetic material 11"!1 resin), 29...resin (magnetic material resin)
.

Claims (2)

[Claims] (1) A non-magnetic resin member molded into a flat plate shape to seal the magnetic sensing element, and a magnetic resin molded to sandwich both the front and back sides of the non-magnetic resin member. A magnetic sensor comprising a member. (2) The magnetic sensor according to claim 1, wherein the non-magnetic resin member is molded to have a thickness thinner at a portion corresponding to the magnetic sensing element described in 01.1 than at other portions.