JPS6370190A - Dark room to electromagnetic wave and acoustic wave - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is designed to detect unnecessary (in some cases, intended) electromagnetic waves and sound waves (both of which are hereinafter referred to as "targeted") emitted by electronic equipment when testing electronic equipment. It relates to a darkroom that can effectively measure wave energy (called wave energy).

(Conventional technology) When designing electronic equipment or in actual practice! On production lines, it is necessary to measure electromagnetic waves emitted by electronic devices under stable conditions with extremely low T4F waves (this measurement is important in recent years as there has been a movement to regulate electromagnetic interference from electronic devices, etc.) ). Similarly, it may be necessary to measure the sound (noise) emitted by electronic equipment under conditions that are stable against sound waves.

Conventionally, we have used radio anechoic chambers and sonic anechoic chambers (no
A sound chamber) was prepared and used for each measurement. Each of these darkrooms has a different configuration from a typical building (room) in order to provide shielding (blocking wave energy inside and outside the room) and darkening (preventing reflection of wave energy inside the room). . For example, an anechoic chamber has a completely sealed housing made of conductors, and a large number of wedges are arranged on the walls of the chamber. Further, the sonic darkroom has a casing made up of walls made of laminated materials with different acoustic impedances, and a large number of wedges are also arranged on the walls of the room.

(The problem that R-mei is trying to solve) Therefore, all darkrooms require large casings (requiring a large installation space) and are expensive structures due to the usable space in the room. There is. Therefore, when both a radio anechoic chamber and a sonic anechoic chamber are required, securing installation space becomes a problem. There is also the problem of high construction costs and maintenance costs.

The present invention has been made in view of these points, and its purpose is to provide a darkroom that can effectively measure wave energy such as electromagnetic waves and sound waves.

(Means for Solving the Problems) The darkroom against electromagnetic waves and sound waves of the present invention that achieves the above object has at least a main wall of a casing laminated with a heavy and thick material and a conductor layer, and a dark room against electromagnetic waves and sound waves. It is configured to include a sliding door made of a material that causes absorption loss of a predetermined amount or more of sound waves, or an inner wall of the housing in which cones are densely arranged.

(Example) Hereinafter, the present invention will be explained in detail with reference to the drawings.

The figure is a configuration diagram showing an embodiment of the present invention, and is a sectional view of a wall portion of a casing that constitutes a darkroom. In the figure, the main wall 1 of the casing consists of a high-density layer (reinforced concrete layer) 2 made of a heavy and thick material such as concrete, wire mesh, galvanized iron plate, aluminum plate, copper plate, etc. (connections are soldered and covered). It has a laminated structure of a conductor layer 3 (layer 3 is grounded), a dielectric layer 4 made of urethane rubber, natural rubber, etc. This housing main wall 1 constitutes a cubic or rectangular parallelepiped darkroom (hexahedral sealed structure) with a completely sealed structure, and the housing inner wall 5 is installed inside it (of course, one of the walls of the housing is (There is an entrance with a door for taking the inspected object in and out.) The inner wall 5 of the housing has a structure in which a large number of patterns 6 are densely arranged, the surfaces of which are covered with an absorber 7 that provides absorption loss of a predetermined amount or more to wave energy. I7y! The main body 6 is made of wood, rubber, plastic, etc., and is fixed to the conductor layer 3 by nails 8. The absorber 7 is made of felt or nonwoven fabric mixed with aluminum, carbon, or the like. Between the wedges 6 (the valley), there is aluminum,
A small piece 9 of felt or nonwoven fabric mixed with carbon or the like is installed.

Note that the length and height of the sliding door 6) fJ defines the minimum wavelength that is effective as a dark room for radio waves and sound waves. A wavelength significantly longer than the length 1 of pattern 6 does not result in an ashless q4 termination. At least 174 wavelengths are required.

In other words, for a sound wave of 10011z, the wavelength is 3.4m.
(However, since the speed of sound = 340 mis>, it is approximately 0.82
cm is required. This value is very similar to the value obtained in Lucara, where the wavelength of 100 HIIZ radio waves is 3 m (however, radio wave speed - 3 x 108 TrL/S). Model 6 in the example is a sound wave of about 100 fiz or more and about 100 H.
No charge for electromagnetic waves over llz! The chamber is constructed to be shielded from sound waves of approximately several H2 and electromagnetic waves of 10 to 82 or more.

In the above configuration, the darkroom has a completely sealed structure with the conductive layer 3, so shielding against radio waves is achieved.In addition, the dielectric layer 4 is laminated on the conductive layer 3. This improves the shielding effect against radio waves.In addition, the darkroom is made of heavy reinforced concrete with a high-density layer 2.
Since it has a completely sealed structure, it is also shielded from sound waves. Also, in the case of this sound wave, the presence of the dielectric layer 4 (consisting of a stack of materials with different acoustic impedances) improves the shielding effect against the sound wave.

On the other hand, since the inner wall 5 of the housing is densely arranged with a large number of wedges 6 covered with absorbers 6 that cause absorption loss of more than a predetermined amount with respect to wave energy, it is difficult to absorb both radio waves and sound waves. A darkroom is realized.

Note that the present invention is not limited to the above embodiments. For example, the inner wall of the casing is made of an absorber 6 (
The wedge itself may be an absorber), a cone whose surface is covered with the absorber 6, or a cone itself constituted by the absorber 6 (the cone itself is an absorber). Alternatively, only the floor of the inner wall of the casing may be constructed of the flat absorber 6. Furthermore, a high-loss dielectric material including rubber or plastic may be used as the absorber. Furthermore, the high-density layer 2, which forms the main part of the main wall of the casing, is made of electrically (electromagnetically) structured conductors (thick welded wire mesh) inserted into concrete, or heavy metal fibers. Concrete may be mixed with lossy conductor pieces such as carbon fiber, carbon powder (carbon black), or lossy magnetic material pieces such as iron oxide powder (red iron oxide) or ferrite.

(Effects of the Invention) As explained above, according to the darkroom against electromagnetic waves and sound waves of the present invention, at least the main wall of the casing in which heavy and thick materials and conductor layers are laminated, and the darkroom against electromagnetic waves and sound waves. Because it is equipped with an inner wall of the housing in which rods or cones made of a substance that causes absorption loss of a predetermined amount or more are densely arranged.
Wave energies such as electromagnetic waves and sound waves can be effectively measured. Therefore, it is possible to improve the space factor and reduce construction and maintenance costs. Furthermore, the sonic characteristics and radio wave characteristics of electronic equipment can be measured simultaneously.

[Brief explanation of the drawing]

The figure is a configuration diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Main wall of the casing, 2... High-density layer (concrete layer), 3... Conductor layer, 4... Dielectric layer, 5... Inner wall of the casing, 6... Wedge, 7... Absorption layer, 8... Nail, 9...
...A small piece of absorbent material.

Claims (6)

[Claims] (1) At least the main wall of the casing is laminated with a heavy and thick material and a conductor layer, and a wedge or cone made of a material that causes absorption loss of a predetermined amount or more for electromagnetic waves and sound waves is densely arranged. 1. A darkroom against electromagnetic waves and sound waves, comprising: an inner wall of a housing; (2) The dark room for electromagnetic waves and sound waves according to claim 1, wherein the wedge or cone itself is made of a material that causes the absorption loss. (3) The dark room for electromagnetic waves and sound waves according to claim 1, wherein the surface of the wedge or cone is coated with a substance that causes the absorption loss. (4) The electromagnetic wave according to claim 1, wherein the inner wall of the casing is composed of a planar floor made of a substance that causes absorption loss, and a side wall and a ceiling made of the wedge or cone. Darkroom against sound waves. (5) The darkroom against electromagnetic waves and sound waves according to claim 4, wherein the floor itself is made of a material that causes the absorption loss. (6) A dark room against electromagnetic waves and sound waves according to claim 4, characterized in that the surface of the floor is coated with a substance that causes the absorption loss.