JPH0529199U - Magnetic shield device for electronic devices - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a magnetic shield device for electronic devices, which can effectively and inexpensively prevent obstacles such as color shift and shaking caused by a disturbance magnetic field in a CRT or the like. According to the present invention, when magnetically sealing an electronic device that is affected by a disturbance magnetic field, a plurality of directional magnetic steel sheets are used as a shield material, and the directional magnetic steel sheet is oriented so that the magnetic field disturbs the electronic device. The magnetic seal device for electronic equipment is characterized in that the easy magnetization axes are arranged so as to cross each other to cover the electronic crisis.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic shield device for removing a functional disorder caused by a disturbance magnetic field in an electronic device such as a television or a display (hereinafter referred to as CRT) for monitoring various data.

[0002]

[Prior Art]

 When a disturbance magnetic field acts on an electronic device, accurate information transmission becomes impossible. For example, in a raw material manufacturing plant such as metal, especially in a material care yard, a monitor device (CRT) is installed at an appropriate place in order to provide the operator with information in real time, such as the tracking state of the material, maintenance instructions, and maintenance results. It is arranged.

In this material maintenance yard, devices such as magnet lifters and magnetic flaw detectors that use magnets are frequently used, and power transmission lines, transformers, motors, etc. are installed. The existing magnetic field acts as a disturbance on the CRT in the vicinity. The disturbance magnetic field acting on the CRT causes a color shift (color shift) in the CRT image when it is a DC magnetic field, and shakes in the image when the AC magnetic field is present, which causes information transmission, which is the original function of the CRT. It causes misunderstanding and inaccuracy, and gives a big obstacle. Therefore, in order to eliminate such obstacles, the CRT is covered with a magnetic shield material.

Conventionally, it is well known that permalloy is used as a material for shielding the disturbance magnetic field. Generally, it is said that a material having a higher magnetic permeability has a magnetic shielding effect in terms of magnetic properties, but permalloy has a high magnetic permeability under a relatively low magnetizing force (H = 3 A / m), As the force increases, it drops sharply. This material is also expensive. On the other hand, amorphous materials have recently been used as magnetic shielding materials, but their magnetic permeability is low.

[0005]

[Problems to be solved by the device]

 In order to solve the above-mentioned current problems, the present inventor has repeatedly studied the magnetic shielding effect of various materials in an area where a relatively high disturbance magnetic field is generated from many directions such as a material care yard, and as a result, A unidirectional electrical steel sheet is extremely effective in preventing color shift and shaking that are more affected by a higher magnetic field, and moreover, the axis of easy magnetization of the steel sheet is made as long as possible in this direction. It was found that the effect can be further enhanced by taking it and arranging it so that it is aligned with the acting direction of the disturbance magnetic field.

That is, the present invention is based on such knowledge and arranges the unidirectional electrical steel sheet at intervals such that the easy axis of magnetization is in the cross direction, and effectively and inexpensively causes the disturbance caused by the disturbance magnetic field. An object of the present invention is to provide a magnetic shield device for electronic devices that can be prevented.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention uses a plurality of directional magnetic steel sheets as a shield material for magnetic sealing of electronic devices that are affected by a disturbance magnetic field, and each of the steel sheets has a different axis of easy magnetization. A magnetic seal device for electronic devices is characterized in that the magnetic seal device is arranged so as to cover the electronic device by arranging and laminating a reinforcing member made of a non-magnetic material so as to be located at the position.

The present invention will be described in detail below. In order to prevent the color shift and the shaking phenomenon of the CRT image appearing due to the action of the disturbance magnetic field, a grain-oriented electrical steel sheet is used in the present invention, but as described with reference to FIG. 1, it must be used in relation to the direction of the magnetic field. If not enough shielding effect does not appear. The grain-oriented electrical steel sheet may be a commercially available silicon steel sheet containing about 3% Si and has an easy axis of magnetization parallel to the rolling direction (hereinafter referred to as the rolling direction), but the shielding effect is halved depending on the method of use. .. That is, it is not necessary to simply process the grain-oriented electrical steel sheet to shield electronic devices such as CRTs, but to process so that the axis of easy magnetization (that is, the rolling direction) becomes longer and to match the direction of the disturbance magnetic field. It is preferable to configure.

Table 1 shows that a permanent magnet (maximum magnetic field 480G) is placed at a position 5 mm away from one surface of the shield material (oriented electrical steel sheet) of the present invention, and 5 mm away from the opposite surface side of the shield material. A magnetic measuring device is installed at a position to measure how much the magnetic field generated by the magnet passes through (leaks) the shield material, that is, the shielding effect of the grain-oriented electrical steel sheet is measured for each shape and size of the steel sheet. It was done. Also, the measurement was carried out when the two shield materials were arranged in the same direction or changed by 90 ° and the material intervals were 1 mm and 5 mm.

[0010]

[Table 1]

From the above results, it is understood that the leakage magnetic flux of the rectangular sample having the long side in the rolling direction is smaller than that of the sample having the short side in the rolling direction. Moreover, among the samples using two squares, the two-ply sample in which the rolling direction is changed by 90 ° is remarkably low. Furthermore, it is clear that the shield effect becomes more noticeable when the gap is slightly (5 mm). It can be said that this is a result of shielding the vertical and horizontal magnetic fields produced by the magnets by the two grain-oriented electrical steel sheets.

Further, as shown in FIG. 1, a cylindrical shield body was produced from a grain-oriented electrical steel sheet, and the shield effect depending on the magnetic field direction was examined. That is, (A) is a shield body a using a rectangular plate 1 long in the rolling direction, and (B) is a shield body b using a rectangular plate 2 short in the rolling direction (the line RD in the figure indicates the rolling The directions of the CRT images were investigated by providing a monitor inside each of them and applying a DC and AC magnetic field in each direction of arrows x, y, and z. As a result, when a magnetic field from the z (front and back) direction was applied to the shield a, color shift and shaking occurred in the image, but in the magnetic fields from the x and y (left and right and up and down) directions, the Distortion was not seen, and the image was clear. With respect to the shield b, color shift and shake were generated by the magnetic fields from the x and y directions, but it was clear in the z direction. This indicates that the image is not affected by the magnetic field parallel to the rolling direction RD, that is, the easy axis of magnetization (fully shielded).

According to the present invention, based on the above-mentioned phenomenon, the easy axis of magnetization of the grain-oriented electrical steel sheet used as the shield material is configured in accordance with the direction of the disturbance magnetic field. That is, if the disturbance magnetic field is the left-right (x) or up-down (y) direction of the electronic device, the configuration is as shown in FIG. 1A, and if the disturbance magnetic field is the front-back (x) direction, the configuration is as shown in FIG. To shield.

However, in the above-mentioned material care yard, the derivation of the disturbance magnetic field is not limited to one direction, but is often multidirectional. FIG. 2 is an exploded view of a composite configuration example of a shield material that shields a disturbance magnetic field in multiple directions. Therefore, the shield body a for the disturbance magnetic field in the x and y directions is an outer material (FIG. A), and the shield for the z direction is shielded. The body b is used as an inner material (Fig. B), and both materials a and b are bonded in between, with a non-magnetic reinforcing material 3 (Fig. C) formed of, for example, a urethane resin having a thickness of 5 mm. FIG. 3 shows an apparatus in which these are assembled. In the figure, 4 is a front cover provided with a CRT exposure hole 5 (Fig. D), 6 is a back cover having a vent hole 7 (Fig. E), and these are one to a plurality of directional electromagnetic fields similar to the main body. Use a steel plate. In the present invention, it is effective that the grain-oriented electrical steel sheets constituting the outer and inner shield materials are stripped so that the rolling direction is long and are formed into a tubular shape before use. In the case where it is difficult to perform the tubular molding, the present invention also includes the combined use of dividing materials having one surface or two surfaces continuously.

[0015]

As described above, according to the present invention, the grain-oriented electrical steel sheets are used, and a plurality of them are spaced with a reinforcing material or the like, and the easy axes of magnetization are crossed so as to match the direction of the disturbance magnetic field. By arranging them in the same direction, it is possible to prevent adverse effects such as color shift and shaking exerted on the electronic device, and it is possible to effectively and effectively provide the electronic device shield device.

[Brief description of drawings]

1A and 1B are perspective views showing an example of a shield member of the present invention.

FIG. 2 is an exploded view of the components of the device of the present invention, (A),
(B), (C), (D) and (E) are perspective views of the constituent members.

FIG. 3 is a perspective view of the device of the present invention.

[Explanation of symbols]

 1: Rectangular plate that is long in the rolling direction 2: Rectangular plate that is short in the rolling direction 3: Reinforcement material 4: Front cover 5: CRT exposure hole 6: Back cover 7: Air hole a, b: Shield material DR: Rolling direction

Claims (1)

[Scope of utility model registration request] 1. When magnetically shielding an electronic device which is affected by a disturbance magnetic field from multiple directions, a plurality of directionally controlled electromagnetic steel plates are used as shield materials, and the easy magnetization axes of the respective steel plates are positioned in different directions. A magnetic shield device for electronic equipment, characterized in that the electronic equipment is covered with the reinforcing material made of a magnetic material so as to be overlapped with each other and covers the electronic equipment.