JPS61134189A - Filter for electromagnetic shield - Google Patents

Abstract

PURPOSE:To shield X rays and the like radiated from a CRT display by piercing plural through holes by the specific pitch and constituting a filter of a plate-like filter main body made of iron having a specific transmissivity, whose one or two sides are blackened, and supporting member fixed to said main body. CONSTITUTION:Plural through holes 4 are pierced by a lateral pitch and/or a longitudinal pitch of 0.10-0.40mm. The titled filter is constituted of the plate- like filter main body 2 made of the iron having a transmissivity of 40-80%, whose one or both surfaces are blackened, and the support 3 fixed on the main body 2. For instance, plural through holes 4 and 4 and a black layer 5 for preventing light reflection are formed on the filter main body 2 and the single surface, respectively. For raw materials of the filter main body 2, a copper foil and iron foil available from cold rolling and electro-casting are used, and foils whose carbon contents are about 0.01-0.1% with a thickness of normally 0.01-0.05mm are preferable. The best thickness is 0.01-0.03mm. For materials of the supporting member 13 glass and synthetic resin are used.

Description

[Detailed description of the invention] The present invention relates to a filter for electromagnetic shielding.

A circular tube (CRT) is used in televisions and combiators.

Widely used in displays for word processors, etc. However, CRTs emit weak electromagnetic waves such as X-rays, and electromagnetic radiation from CRT displays can be a problem, especially when operators work in close proximity to the CRT display for long periods of time, such as when operating a computer or word processor. ), improvement was desired.

The present invention has been made in view of the above points, and an object of the present invention is to provide an electromagnetic shielding filter capable of shielding electromagnetic waves such as X-rays emitted from a CB'l'' display or the like.

That is, in this III, a plurality of holes are bored at a pitch in the horizontal direction and l or a pitch in the vertical direction from 0.10 to 0.40■, and the transmittance is 4.
0 to 80%, and one or both sides are blackened. The gist of the present invention is an electromagnetic shielding filter characterized by comprising a plate-shaped filter body made of iron and a support member fixed to the filter body.

Three embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a vertical cross section 'rMt of an electromagnetic shielding filter 1 of the present invention, which includes a plate-shaped filter body 2 made of iron, and a plate-shaped support covering both sides of the filter body 20. Separated from the material 3, the filter body 2 is provided with a plurality of perforations 4-, and a black layer 5 for preventing reflection of WK light is formed on one side.

The material for the filter body 2 is cold rolled.

Steel foil or iron foil obtained by electroforming or the like is used, but one with a carbon content of about 0.01 to 0.1% is preferable, and the thickness is usually 0.01 to Q, 95 m, more preferably 0601-0.03g.

In addition, when forming the through holes 4, 4- by an etching method as described later, the material of the filter body 2 is carbon:
0.01-0.1%, manganese 20, 20-0.40%
, silicon: Q, 04% or less, phosphorus: 0.030% or less,
Sulfur: o, oao% or less, aluminum: 0.02-0
．． 080. % iron by cold rolling method 50.01~0.0
4 m thick, tensile strength 71C9/1 or more, cleanliness (according to JIS G 0555) 0.033%
It is particularly preferable to use a rolled steel foil having the following properties, and since it has sufficient tensile strength, it can be easily processed by a continuous etching method in the form of a long coiled steel foil. Steel foil with a carbon content of less than 0.01% will not have a tensile strength of Yoke/- or more, and if it exceeds 0.1%, the cleanliness will not be less than 0.033% due to carbide impurities, and manganese Temperature B with content less than 0.2Q%:
Brittleness tends to occur during hot rolling prior to rolling, and if it exceeds 0.040%, the work hardening of the steel is too severe and stable rolling becomes difficult. Also silicon content.

If the phosphorus content and sulfur content exceed the above range, the cleanliness will not be lower than 0.033%, and furthermore, since aluminum acts as a deoxidizer for steel, the aluminum content will be 0.02%.
If it is less than 0.08%, the deoxidizing effect is insufficient.
If it exceeds this, aluminum oxide-based impurities will increase and the cleanliness will not be below 0.033%. Cleanliness is 0.033
%, the shape of the through holes 4, 4- will be distorted and become large when the through holes 4, 4- are processed by the etching method. is not formed. If the thickness of the rolled steel foil is less than 0.01 mm, the tensile strength will be insufficient, and if it exceeds 0.04 mm, the through holes 4 and 4 will be formed by etching.
Therefore, the preferred thickness of the steel foil is 0.01 to 00031o11. Further, if the tensile strength of the steel foil is less than 70/9/fi, sufficient tension cannot be applied.
m'' or more, it is necessary to control the carbon content and rolling reduction of the steel foil, but if the carbon content is less than 0.01%, the necessary tensile strength cannot be obtained even if the rolling reduction is increased.

Therefore, tensile strength can be improved by increasing the reduction rate within the range of carbon content 0.01 to 0.03%.
The rolling reduction ratio is preferably 60% or more. The shape of the through holes 4, 4- is not particularly limited.

For example, circular shape (Fig. 2 (A)), elliptical shape, triangular shape, square shape, rectangular shape (Fig. 2 (C)), hexagonal shape (Star 2 r! A (B)), slit shape (2nd @
(D)) It can be formed into an equal stacked shape. Also, the arrangement pattern of the through holes 4°4- is such that both the horizontal and vertical columns are arranged on a straight line as shown in Fig. 2 (M); Fig. 2 CB)
As shown in Figure 2(C), the horizontal rows are arranged in a straight line and the vertical columns are arranged in a staggered manner. Further, although not particularly shown in the drawings, there may be mentioned the following modes, such as a mode in which both horizontal and vertical rows are arranged in a staggered manner.

In the present invention, as described above, various shapes and arrangement patterns of the through holes 4, 4-- may be adopted;
, 4- horizontal pitch or vertical pips (2nd r!A
(lateral pitch): d is 0.10~Q, 4Q
w, preferably 0.10 to 0.301, and the transmittance of filter 1 is 40 to 80%, preferably 50 to 7
It is necessary to be 5%. If ds<0.10 dew, manufacturing becomes difficult.

dl) In the case of 0.40 dew, the shielding effect decreases.

Further, if the transmittance is less than 40%, it becomes too dark and it becomes difficult to see the display on a CRT display, etc., and if the transmittance exceeds 80%, the shielding effect against electromagnetic waves such as X-rays is reduced.

In the present invention, the pitch in the horizontal direction (or pitch in the vertical direction) is at least 0.10 to 0.40 and the through hole is 4°4.
- It is necessary to drill 1, for example, 1 as shown in the second @.
When circular through holes 4, 4- (t or square through holes, etc. not particularly shown) are arranged on a straight line in both horizontal and vertical rows, the vertical pitch: d8 is also 0.10 to 0.40 fi. It is preferable that In this case, the horizontal pitch: dl and the vertical pitch: dl may be the same or different.

To form the through holes 4,4-t, for example, an etching method is adopted, and in this method, first, PTA and ammonium dichromate are applied to both sides of steel foil or iron foil obtained by cold rolling, electroforming, etc. A water-soluble photoresist solution consisting of is applied and dried to form a photoresist layer, and then the surface on which the photoresist layer is formed is coated with a predetermined pattern. The photoresist layer is exposed to a predetermined pattern by irradiating it with ultraviolet rays or the like. Next, after washing with water at 50 to 60°C to dissolve and remove the unexposed 7-photoresist layer (portion coated with a light-opaque coating), the photoresist layer is washed with water at a temperature of 50 to 60°C, and then sprayed with a ferric chloride solution or the like. The iron in the portions where the photoresist layer has been removed is dissolved to form through holes 4, 4-.

In addition to the etching method, it is also possible to manufacture iron foil or steel foil by electroforming using a plate having a large number of needle-like protrusions, and simultaneously form through holes 4, 4- corresponding to the locations of the needle-like protrusions. can.

After forming the through holes 4, 4- as described above.

The filter body 2 is obtained by forming the black layer 5.

One example of a blackening treatment method for forming the black layer 5 is 1f (
() A method of heating the filter body 2 to 450 to 600°C in steam or natural gas decomposition gas to oxidize 9 surfaces 't' to form a black iron oxide (Fe104 etc.) film;
(H) Black plating on the surface of the filter body 20,
Method of applying black nickel plating, G-→After applying copper plating to a thickness of Ooo O3 to 0.050 wg on the surface of the filter body 20, the surface is coated with, for example, 5% sodium aqueous solution and 1% potassium persulfate. Examples include a method of forming a black cupric oxide film by applying chemical @salt treatment, such as boiling an aqueous solution at a temperature of 100° C. or higher for about 3 to 10 minutes. When the above method (c) is adopted, it becomes possible to sufficiently shield relatively low frequency electromagnetic waves for which the shielding effect is insufficient with iron alone.

A support material 3 is fixed to both sides of the filter body 2, and the first
The electromagnetic shielding filter 1 of the present invention shown in the figure is formed. The support material 3 is not limited to one that is fixed to cover both sides of the filter body 2, but may be one that is fixed to cover only one side of the filter body 2, or one that is fixed to only the four circumferences of the filter body 2 in a frame shape. However, it is preferable that the filter be fixed so as to cover one or both sides of the filter body 2. Examples of the material for the support material 3 include glass, synthetic resin, etc., but when it is fixed to cover both sides or one side of the filter body 20, a material with good transparency such as glass, transparent acrylic resin, etc. can be used. preferable.

The support material 3 is fixed to the filter main body 2 with adhesive or the like, but if the support material 3 is made of synthetic resin, the filter main body 2 is installed at a predetermined position inside the molded product, and the resin is attached to the base. It is also possible to use a method such as pouring into a waterfall.

For example, as shown in FIG.
Kjp CRT 7
Two inventive filters It-CR are used by being attached to the front.
By attaching it to the T display 6, harmful electromagnetic waves emitted from the pcRT 7 can be very effectively shielded.

Although not particularly shown, the method for installing filter 1 is C.
The filter is not limited to being fitted into the exterior body of the RT display 6, but may be attached to the front surface of the CRT 7 by a method such as providing a locking member on the filter and locking the WK outside the exterior body of the CRT display 6.

In the above embodiment, the case where the black layer 5 was provided on one side was explained, but the #11 color layer 5 may be provided on both sides.

As explained above, the electromagnetic wave shielding filter of the present invention has a horizontal pitch and/or a vertical pitch of 0.10
-Drill multiple holes at ~0.40cm, transmittance 40~80
%, by having a plate-shaped filter body made of iron, it can sufficiently transmit visible light and reliably block harmful electromagnetic waves such as X-rays emitted from CRT displays, etc. Moreover, since the support material is provided on the filter body, the strength of the entire rounded shape can be improved. In addition, since the filter body is blackened on one or both sides, it is necessary to attach it to the CRT with the blackened side facing the viewer, thereby preventing extraneous light from interfering with the viewer's viewing of the CRT display. This has the effect of preventing reflection on the filter surface.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a vertical cross-sectional view of a main part of an electromagnetic shielding filter, and FIGS. 2 (A) to (D)
3 is a schematic diagram showing different patterns of arrangement of through holes, and FIG. 3 is a longitudinal cross-sectional view of a main part of a CRT display to which the electromagnetic shielding filter of the present invention is attached. 1-Electromagnetic shielding filter 2--Filter body 3--Support material 4-Through hole 5
-black layer

Claims (1)

[Claims] Horizontal pitch and 1 or vertical pitch 0.10-0.4
A plate-shaped filter body made of iron and having a transmittance of 40 to 80% with a plurality of holes of 0 mm in diameter and blackened on one or both sides, and a support material fixed to the filter body. An electromagnetic shielding filter characterized by comprising: