JP2002526937A - Protection device for electric circuit against interfacial micro discharge phenomenon - Google Patents

Abstract

(57) Abstract: The present invention is from ^{0.004 · 10 -3 Ω × m 5} · 10 - at least one protective device comprising an electromagnetic absorbing coating having a specific electrical resistivity to be within the scope of up Omega ³ × m The present invention relates to a device for protecting an electric circuit against interfacial micro-discharge phenomena, including (1) and enabling attenuation of interfacial micro-discharge phenomena. The device is useful for protecting components of audio and video frequency devices.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0003] Hereinafter, interfacial microdischarge, called MDI, emerges as a phenomenon that is a major cause of degrading the transfer and detection of electrical signals. Even devices that meet conventional noise reduction standards and standards are associated with reduced fidelity, which is manifested in audio or video frequency signal processing devices such as high fidelity or high fidelity stereo devices. In particular, such a phenomenon appears.

Such microdischarges occur each time a charge coupled to an insulator is affected by a changing electric field, especially when it is present at the interface of the insulator. In addition, the phenomenon of microdischarges often occurs when mechanical vibrations are present and their source is an electronic or electrical circuit.

[0003] In short, these charges are localized on the surface of the electrical insulator described above. That is,
It is localized at the conductor / insulator interface itself, as in the case of electrical or electronics cables, or at the junction of two insulators, as is always the case at the insulator / air interface.

The electric field that is the excitation source of such microdischarges has a source inside it, or, for example, an electric field generated by a local power grid with industrial frequency,
There are sources outside.

[0005] A new equilibrium of the electrostatic system thus formed, when one electric charge or the whole electric charge coupled to the electrical insulator is subject to a changing electric field, causes a microdischarge to occur. It can only be obtained through a microdischarge phenomenon, which is analyzed as a local dielectric breakdown phenomenon according to the roughness of the insulator and / or conductor material contained therein.

[0006] Such microdischarges have very small amplitudes, on the order of millivolts, but exhibit very short rise or fall times, less than nanoseconds. Therefore,
Corresponding measurements made it possible to reveal the frequencies associated with these transients and to show that the radio waves generated by the MDI ranged from 1 GHz to more than 100 GHz.

At such a level of frequency, and because of the way it is generated, the above-mentioned electromagnetic phenomena propagate in the form of electromagnetic waves, hereinafter referred to as MDI waves,
It propagates in the form of electromagnetic waves along insulator, insulator / insulator and insulator / air interfaces.

[0008] Because excited by an electric field, the MDI phenomenon is synchronized with the electric field, so that
Such electric fields or vibrations will produce correlated electromagnetic waves, if not modulated.

[0009] All of the above-mentioned high frequency metal / metal connections exhibit significant rectification characteristics. As a result, such a connection effectively re-radiates the MDI in the useful signal, albeit correlated to the excitation field, but very distorted.
Plays a disturbing role in wave detection. The resulting signal eventually feels very distorted, especially to the average audiophile.

[0010] The excitation field is an intrinsic source, but mechanical oscillations and, of course, external electrostatic fields are also auxiliary sources.

In particular, the presence of an external electrostatic field does, by virtue of the overlap of several equilibrium states, indeed facilitate the release of charge when the excitation field changes. From the opposite perspective, this phenomenon is confirmed by the known use and effectiveness of antistatic products for cables or other mechanisms of Hi-Fi devices.

[0012] For these devices, mechanical vibrations manifest themselves as a significant MDI multiplication factor. Such vibrations result in at least a temporary reduction in the electrical breakdown distance, thereby increasing the amount of MDI generated. The presence of such mechanical vibrations is, of course, a significant problem for audio or hi-fi devices whose primary technical effect is to vibrate the surrounding air with a loudspeaker or the like.

Moreover, since such vibrations are strongly correlated with the audio frequency signal, MDIs generated under these conditions have the property of perceptibly disturbing the hearing.

To date, various studies have been conducted on MDI itself and its eradication.

First, the results of the work done by Pierre Joanne can be quoted below.

During this study, MDI could be detected using dipole or dipole antennas from 4 to 10 cm.

The MDI has been identified in particular in the following components: In the amplifier: the signal generated by the MDI is correlated in the fundamental low-frequency band with the input signal, and the repetition amplitude and frequency of the signal generated by the MDI change according to this input low-frequency signal Has been confirmed to a completely significant extent. -In local power grid cables-and in loudspeakers: a particularly important phenomenon, since the amplitude of the input voltage does not exceed a few volts in this case, and these voltages are exclusively low frequency.

In accordance with these early studies, several different solutions have been proposed by Pierre Joanne. These solutions are described in French patent applications Nos. 96 12369, 97 06045 and 9 filed under the name of "French Electric Power Corporation".
No. 7,078,737, which is also fully incorporated herein by reference.

The solutions proposed in the above mentioned applications are satisfactory. This solution basically attenuates the exciting or electrostatic electric field, absorbs the MDI as it is generated, reduces or eliminates unwanted mechanical vibrations, and reduces intermediate electrical Or by removing the disturbing electrical signals generated by the MDI at the input and output of the electronic circuit by means of a passive filter employed, by generating local equipotentials near the interface for the purpose described above. ,
Avoid generating MDI.

Next, the work done by Pierre Fontaine can be quoted as well.

[0021] The study confirmed the following at the input of the working audio frequency amplifier: That is, when a signal having a small amplitude not exceeding 500 mV, but exceeding 200 kHz, is superimposed on an audio frequency signal which is a basic band of about 10 Hz to 20 kHz, the sound generated by the resulting output signal becomes Hard, distorted (strained), and in a word, very uncomfortable.

Third, a paper published by Olivier Drouin, Jacques Baudet, and Bernard de Moulin in the magazine "Electricians and Electronics Engineers", No. 1, January 1998, The characteristics of operational amplifiers that receive signals at much higher frequencies can also be cited below. The above studies show that the presence of an interfering signal, whose frequency is on the order of 700 MHz, greatly disrupts the operation of the operational amplifier.

Fourth, the distortion measurement performed on the audio frequency amplifier, ie, the resulting difference between the output signal and the input signal attenuated by the gain value of the amplifier, is 1-2 GHz. The interference signal in the band up to was confirmed.

Fifth, it must be noted that high emissions at high frequencies have been observed during the compliance testing of amplifiers or other devices with open covers to electromagnetic compliance standards.

Finally, the improvement in sound quality and its effectiveness obtained through the use of microwave absorbers and other extremely high frequency filters clearly, albeit indirectly, indicates the presence of noise phenomena generated by MDI. I have.

It is an object of the invention to remedy the deficiencies of previously proposed solutions by realizing a new solution or a supplementary solution related to this method.

Therefore, another object of the present invention is to suppress the generation and propagation of interfacial micro-discharge waves (MDI waves) due to the interfacial micro-discharge (MDI) phenomenon.
An object of the present invention is to realize a protection device for an electric circuit against the phenomenon I.

[0028] Yet another object of the present invention is also an audio and / or video frequency comprised of active or passive elements that may generate the MDI phenomenon and the MDI waves resulting from this phenomenon. It is an object of the present invention to provide a device for protecting an electric circuit against interfacial micro-discharge phenomena that can occur in most of its components.

A device for protecting an electric circuit against an interfacial micro-discharge phenomenon which is a source of radio noise at an audio frequency has at least one protection element formed of an electromagnetic absorbing film, and its specific electric resistance is 0.004 × 10 ⁻³ Ω × m to 5 × 1
It is in the range up to 0 ^-3 Ω × m and has the advantage that this absorbing coating can attenuate the interfacial microdischarge phenomenon.

The protection device according to the invention is preferably, but not exclusively, applied for the protection of all components of an audio and / or video frequency device. For protection of the active components of the audio and / or video frequency device, such as amplification circuits, electrical supply circuits or loudspeakers, or electrical connection cables,
It is applied for the protection of passive components such as supply cables, recording and playback media for audio and / or video frequency signals and the like.

This device, which is the subject of the present invention, will be better understood on reading the following description made with reference to the accompanying drawings, given by way of non-limiting example only.

A more detailed description of a device for protecting an electric circuit against the phenomenon of MDI according to the object of the present invention is given below with reference to FIG.

A protection device for an electric circuit according to the object of the invention generally relates to all circuits or all objects having the function of generating a potential and / or a current. More specifically, to generate electrical charges, currents and potentials that interfere with the electrical supply or transfer of electrical signals with information to other electrical circuits or during the use of these circuits or objects By doing so, these electrical circuits and objects that are the source of electrical phenomena may then cause interfacial micro-discharge phenomena that can be sources of radio noise at audio frequencies, relating to all circuits or all objects It is.

As a result, within one non-limiting embodiment, the circuit shown in the cross-sectional view of FIG. 1 includes a resistor R, a capacitance C, embedded in a printed circuit board PCB.
It is a printed circuit comprising elements such as a transistor T and a self-inductance L.

According to one particularly prominent aspect of the protection device, which is the subject of the present invention, its specific electrical resistance ranges from 0.004 × 10 ⁻³ Ω × m to 5 × 10 ⁻³ Ω × m. The protection device includes at least one protection element 1 formed by an electromagnetic absorbing coating. The electromagnetic absorbing film 1 can attenuate the MDI phenomenon by absorbing the MDI wave.

FIG. 1 shows an absorbent coating completely surrounding and enclosing the circuit in order to ensure complete protection. However, as shown in the above figures, the electromagnetic absorbing coating mounted near the metal shielded surface of the printed circuit board PCB, i.e., the surface opposite the surface containing the components, in order also to prevent a short circuit between the metal shield in the metal shielding surface of the printed circuit board PCB, to be composed by an electromagnetic absorbing coating 1 ₀ in the proper sense of the layer 1 ₁ of electrically insulating material are superposed preferable.

With respect to the specific electric resistance value, 1 is determined for the electromagnetic absorbing film.
It should be pointed out that the above resistance values are given as an example for various products having a surface coating thickness of from 0 ^-3 mm to 0.5 mm. Under these conditions, the resistivity will be expressed as surface resistance in ohms per unit square for that thickness.

In a first embodiment, as shown in FIG. 2a, the electromagnetic absorbing coating can be constituted by a composition consisting of organic fibers covered by a conductor coating. In such a case, the composition is a non-woven element, which is a so-called non-woven fabric, formed on the basis of metal or organic fibers, particularly carbon or polymer conductors, optionally shielded by a conductive metal. is there. At that time, the parameter of the surface resistance is selected according to the percentage of the conductive fiber used.

According to another embodiment shown in FIG. 2 b, the electromagnetic absorbing coating 1 can be constituted by a fabric formed from woven conductive fibers. The fabric has a flexible surface that is resistant and is a regular collection of fibers that are entangled (woven) or woven or knitted. In this case, such fabrics are basically used in the semiconductor industry to limit the static charge in the manufacturing process. Such fabrics can also be used to protect hermetically sealed enclosures against radiation and / or incident electromagnetic radiation. Particularly suitable cloths available on the market are, in France and Europe, Rochesterlan 4,8470, Distel, product name IS by Schlegel BVA of Belgium.
This cloth is commercially available as OWAVE. The above fabric has a thickness of 0.
It shows an impedance of 05 ohm and a very high electromagnetic wave absorption of about 100 dB in the frequency band of the radio signal from 1 GHz to 10 GHz. In all cases of the tests performed, such fabrics are generally 65 dB depending on the experimental conditions.
, Which is 30 to 40 dB higher than that of a commonly used absorbing substance.
It was confirmed that the absorption rate was large.

Such fabrics are available, on the one hand, as copper metal variants and silver metal variants, which have a higher resistance per unit square, and, on the other hand, are particularly thin, light and very easy to handle, at 40 g / g. As long as it has a mass not exceeding m ² , it appears to be very suitable, in particular, for constituting an electromagnetic absorbing coating constituting a protective device according to the objects of the present invention.

Further, in order to ensure the adhesion between such a circuit protection device and the circuit to be protected, in accordance with the object of the invention, as shown in FIG. For the coating of some devices or components, they can be formed by thermoforming and finally molded in a mold.

Finally, as shown in FIG. 2 c, the electromagnetic absorbing film 1 can be formed by an electromagnetic absorbing film, which, of course, corresponds to the numerical range mentioned above in this document. It has a surface electrical resistance value. However, in such a case, the electromagnetic absorbing film is placed on a substrate S, which is, for example, an MDI interface with an insulator / conductor interface.
Is the insulating layer of the electrical or electronic conductor that is the source of this phenomenon. As a non-limiting example, as will be shown in more detail later in this document, such an electromagnetic absorbing coating 1 may be constituted by a cloth of semiconductor material which is a plastic film containing conductive particles, The membrane 1 is placed on a substrate S.

According to the object of the present invention, a device for protecting an electrical circuit against the phenomenon of MDI, more particularly from a rotating recording medium of signals or data of audio and / or video frequencies, A protection device for protecting a reproduction electric circuit of a video frequency signal or data recording medium in the reproduction device will be described below with reference to FIGS. 3a and 3b.

FIG. 3 a relates to the protection of LP records, labeled DMS,
In normal use, this record is used to ensure that the LP record DMS is reproduced by the read head TLF supported by the tone arm BL.
It is placed on the turntable PR of the reproduction table TL.

As you know, LP records are made of a vinyl-like material, which is particularly electrostatically charged and is famous for attracting dust and other particles present in the air.

Such a phenomenon causes a dry noise caused by an MDI phenomenon that generates audible noise or by friction between dust accumulated on an LP record and a diamond of a read head TLF.

Indeed, the permanent friction of the needle in the groove of the LP record continuously generates microdischarges that are highly correlated with the read signal.

These microdischarges propagate by surface waves to the surface of the LP record and are captured by the read head and then re-emitted via the read signal in the amplifier circuit, so that, by detection, Noise occurs.

According to a particularly notable aspect of the protection device, which is the subject of the present invention, this protection device is provided on a turntable PR, on which an LP record DMS and a turntable are located, as shown in FIG. 3a. Between the PR and the PR, it is advantageous to match the form and dimensions of the turntable PR with the protective element constituted by the electromagnetic absorbing coating 1. It is.

In one non-limiting embodiment, the protective element 1 comprises four layers of a copper metal non-woven fabric for absorbing said high frequency electromagnetic waves, having a thickness of 0.1 mm, marketed by Schlegel. It consists of a panel cover made of In this way, a remarkable improvement in the re-accuracy of the LP record DMS was consistently observed.

Furthermore, as shown in the cross section in FIG. 3 a, as a supplementary measure, the read head TLF is wrapped by a cover constituted by a protective element formed on the absorbent coating, except for the support shaft of the needle only. be able to.

FIG. 3 b shows the application of the protection device according to the invention to an optically readable compact disc, labeled CD. In this case, the read head TLF is constituted by a laser which enables reading of on the reading surface CD ₁ compact disc CD, the reading surface CD ₁ is cut is covered by a metal shield ME is constituted by a polycarbonate layer, and the opposing surface CD ₂ of the reading surface, for example, a varnish layer V which is applied onto the litho the surface and the metal shielding ME silkscreen.

According to a particularly notable aspect of the protection device, which is the subject of the present invention, this protection device is, as shown in the cross section of FIG. 3b, of a compact disc CD placed on its drive. This is achieved by placing the electromagnetic-absorbing coated disc 1 on the compact disc CD, ie on the varnish layer of the compact disc CD. It is an advantage that the electromagnetic-absorbing coated disk 1 can in this case be of the same dimensions as a compact disk CD. This may be constituted by a woven fabric marketed by Schlegel, as described above in this document. In this case, there is one hole at the center of the dimensions of the drive capstan of the compact disc CD and also at the center of the dimensions of the electromagnetic-absorbing coated disc 1 superimposed on this CD.

Utilizing an absorbent coated disk as shown in FIG. 3b, as described above, showed a significant improvement in the overall device reproducibility when replayed by optical reading.

Although a compact disc would originally seem to be less susceptible to electrostatic phenomena than LP records, the higher the rotational speed of the compact disc, the more likely it is to cause electrostatic discharge phenomena in the air. is there.

Moreover, the reading laser beam itself generates a microdischarge at the metal shielded ME / polycarbonate CD ₀ interface due to the photoelectric effect. Thus, such electromagnetic waves propagate through the thickness of the compact disc CD and are then likely to be captured by the reading circuit.

Certainly, the above phenomenon can be confirmed as follows. During a read operation of a compact disc CD, after a transition to the sleep mode for several tens of seconds, a new transition to the read mode allows a much clearer and clearer signal to be confirmed, and amplification at low frequencies Impression and a more gradual sense of distance between the sound source and the viewer can be clearly perceived. In the rest mode, the reading laser beam scans the same reading range, so that the excitation of these same bands by the laser beam leads to the extinction of the MDI phenomenon and, of course, reduces the noise phenomenon associated with said phenomenon.

Some of the major phenomena that contribute to the generation of MDI during rotation of an optically readable CD type recording / playback medium are as follows. -The discharge of static electricity due to friction between the insulating surface of the CD medium and air-the photoelectric effect of the laser beam on the aluminum layer holding the digital information, i.e. the metal shield; I could conclude that Indeed, the treatment of CD media with a mere antistatic product will vary depending on the playback device, but the protection device against MDI with an electromagnetic absorbing coating according to the purpose of the present invention is a reversal reading type playback device. A very consistent subjective result is obtained with any type of playback device, including.

This superiority of the photoelectric effect is explained by the material composition of the CD medium. In general, the reading surface CD ₁ is made of aluminum, comprising a metal shield ME from 0.6 to 0.8 nm (nanometers) thick, which is placed on a 0.8 mm thick cut polycarbonate. It is formed by a shielded thin layer, and an epoxy varnish layer having a thickness of 7 μm to 8 μm is formed on the metal shield.

An extremely thin metal shield ME (lighted bulbs see through this shield) does not serve as a reflective shield for electromagnetic waves. Therefore, virtually most of the electromagnetic waves caused by the induced MDI phenomenon by photoelectric effect it is sent to the non-read surface CD ₂ CD media.

Moreover, these electromagnetic waves are only due to CD media and reading laser beams. Such electromagnetic energy is either not absorbed into the material making up the CD medium and is emitted through the blank surface of the CD medium, or-from above and below in conventional playback devices-TEAC-type reading and playback devices and pioneers In the case of a reversible read / write device of the type, it is emitted from the reading surface;

The electromagnetic waves associated with the MDI phenomenon thus disturb nearby analog circuits according to the classical process of this kind of phenomenon.

Therefore, it seems essential that electromagnetic waves accompanying the MDI phenomenon be absorbed as completely as possible at the CD medium.

Thus, the possibility of using various types of electromagnetic absorbing coatings has arisen, but some protective elements which have proven to be particularly effective are: a) Reference number NWMP. Bristol coated on both sides with a conductive polymer silver non-woven fabric (commercially available under 61027)
B) a type of fine cardboard) b) a reference IWCO. Protective element composed of a disc-shaped electromagnetic absorbing coating made of a copper non-woven fabric commercially available under the trade name 60830 c) Absorbing coated disk composed of a soft conductive polymer film, as shown in FIG. in the form of a disk 1 which is actually superimposed on the disk CD, or similarly layer 1 as shown in FIG. 3b ', on the outer surface of the layer of polycarbonate CD _0, for example, the reading surface side Various materials have been particularly subject to definitive testing to utilize absorbent coated discs in the form of added discs.

The disc 1 to be overlaid on the compact disc CD was made of the following materials. A nickel-copper nonwoven, commercially available under the trademark Electron, reference number 3027-217, having a thickness of 0.487 mm and a surface electrical resistance of 1 ohm per square,
MP, 3481 Rider Trail South, St. Louis MO63045,
Products supplied by USA-Soft PVC discs, reference number G406AS-Elson / DC manufactured by Sekisui Chemical under the reference number PVC G405-AS, 0.1, 0.3, 0.5
mm with a surface resistance of 10 ⁸ to 10 ⁹ ohms / square-an absorbent coated disk made of copper non-woven or silver-nickel non-woven, each reference number being WCO. 60830 and NWMP61027, Schlegel BVA
Company products. This disc can be used for both optically readable compact discs and LP records.

Regarding the use of soft PVC absorbent discs marketed by Sekisui Chemical,
The absorbent coated disk can be fixed to each optical disk, or can be used in different ways, as the case may be.

With respect to absorbing coatings made in the form of electromagnetic absorbing films, such absorbing coatings can be used with any optically readable digital disc, for example a digital sound disc (
DSD) or digital video disc (DVD) is shown to be available.

In such a case, the digital disc can be coated with an intrinsic semiconductor product at the final stage of the process, for example, by simple spraying, vapor deposition, and then centrifugal coating. A particularly advantageous product can be constituted by semiconductor products manufactured under the trademark BAYTRON by the company Bayer Chemie in Germany and marketed.

This product has the advantages that the surface resistance can be adjusted in a wide range of numerical values, and that it is transparent to ultraviolet rays, hardly corroded, and stable.

By means of a special test using the product BAYTRON, the facing surface CD ₂ facing the reading surface in order to form the film labeled 1 in FIG. 3b.
Good results are obtained by treating the so-called label side, which corresponds to the above, and by treating the free side of the polycarbonate CD ₀ to form a film 1 ′ as shown in FIG. 3b. It was shown to be. Film 1 '
Are transparent to the wavelength of the reading laser beam.

Under these conditions, the optimal resistivity of the film thus produced is about 0
. 68 ohms / m, which is 0 per square for a thickness of 1 μm.
. This corresponds to a resistance of 68 · 10 ⁶ ohm.

For example, it is necessary to adjust the specific resistance of the material BAYTRON, the amount of deposition, the rotation speed of the disk, and the time of this rotation anyway in order to diffuse the film accurately over the surface to be protected. It is possible.

The protection device, which is the object of the invention shown in FIG. 3 c, is similar to that in FIG.
There are advantages that has a conductive device reference numerals 2 ₀ being in electrical contact with the electromagnetic absorber film disk 1 via. Conductive device 2 ₀ and the conductive elements 2 ₁ of the assembly, for example, in order to release the electrostatic charge accumulated in the vicinity of the electromagnetic absorption film disk 1, the damping resistor RT, that is connected to the ground. Installing the assembly properly, and as can one radial and the alignment of the radius of the compact disk CD, is constituted directly by the conductor elements 2 ₁ and the conducting device 2 ₀ in contact with the electromagnetic absorber film disk 1 and that assembly is particularly want to understand that it is connected about an axis 2 _0.

Another embodiment of an electromagnetic-absorbing coated disk according to the object of the present invention, as shown in FIG. 3 d, comprises a fabric or cloth as described above in this document, reference numeral 1. ′, On which a second magnetically absorbing coating disk with the reference number 1 is superimposed. It has been shown that, depending on the quality of the material employed, the first and second electromagnetically absorbing coated disks are equally satisfactory.

A description of a particularly advantageous embodiment of a multilayer electromagnetically absorbing coated disk according to the object of the present invention is given below in connection with FIG. 3e.

According to the above figures, the electromagnetic absorption coating 1 is indeed formed by a plurality of electromagnetic absorption coatings 1 a, 1 b, 1 c, 1 d superimposed to form a multilayer composite electromagnetic absorption coating. According to one particularly notable aspect, each continuous electromagnetic absorbing coating from 1a to 1d progressively increases from a contacting electromagnetic absorbing coating that is in physical contact with the recording medium to the next coating. It has specific electric resistances ρa, ρb, ρc, and ρd, respectively. Therefore, the outer electromagnetic absorbing film 1d on the opposite side of the electromagnetic absorbing film 1a in the sandwich structure thus formed is made of a material having a considerably large electrical insulating property whose specific resistance ρd exceeds 10 ⁸ Ω × m. It is configured.

In one preferred embodiment, the electromagnetic absorbing coating 1a is manufactured by Schlegel BVA under the reference IWCO. 60830, which was made of a copper nonwoven fabric under the trade name ISOWAVE. The electromagnetic absorbing film 1a has a specific electric resistance ρa expressed by the following equation: specific electric resistance ρa = 0.04 · 10 ⁻³ Ω × m. This corresponds to a surface resistance of 0.04Ω per unit square. The electromagnetic absorbing coating 1b is available from Schlegel BVA under the reference NWMP. 61027, which has a specific electrical resistance ρb expressed by the following formula: specific electrical resistance ρb = 0.25 · 10 ⁻³ Ω × m. This corresponds to a surface resistance of 0.5Ω per unit square for a thickness of 0.1 mm. Electromagnetic absorbing coating 1c is 2 ^× 10 ^-3 to 3 · 1 with respect to the thickness of the 0.3~0.5mm
It consisted of a dissipative PVC material with a specific electrical resistance ρc of up to 0 ⁻³ Ω × m.
The material used was a product marketed by Sekisui Chemical under the reference G406 AS-ELSON / DC. The electromagnetic absorbing film 1d was made of a polypropylene plastic foil having a thickness of 0.1 mm and a specific resistance ρd> 10 ⁸ Ω × m. For multi-layer electromagnetic absorbing coating applications, foils of the above materials are overlaid, then glued with an aerosol adhesive by pressure, and further, an outer diameter of 12 cm, an inner diameter of 16 mm
Is cut to the size of a recording medium such as a compact disc CD.

According to experiments, it is advantageous to insert an insulating foil of the type used in overhead projectors, having a thickness of 50-150 μm, between the protective device and the compact disc CD, instead of making direct contact. It became clear. In addition, as shown in FIG. 3f, instead of laminating several absorbing foils having different specific electrical resistance values as described above, reference numeral IWCO. 608
30 or a nonwoven fabric manufactured by Schlegel BVA or reference number NWMP. 6
It is also possible to use 3 to 5 foils of silver nonwoven fabric manufactured by Schlegel BVA, which is 1027. In this case, four nonwoven foils 1a, 1b, 1c, 1d are shown in FIG. 3f, the various layers being adhered using an aerosol permanent adhesive. At that time, improvements are brought about by performing the following. Using a carbon non-woven coating instead of a copper non-woven, or depositing a very small amount of graphite at the copper-copper interface or inserting a graphite coating. In FIG. 3f, this coating is represented by a dashed line between the layers 1a and 1c, 1a and 1b, and 1b and 1d. Reference number IWCO. The 60830 copper nonwoven fabric absorbent layers 1a, 1b, 1c and 1d made by Schlegel BVA have a capacity of 0 per unit square.
. It has a surface resistance of 05 ohms and a thickness of 0.1 mm.

The diversity of the absorbing material employed in this way makes it possible to expand the absorption band of the radiated radio wave. Similarly, a gap is created by inserting an insulating layer 1e between the compact disc CD and the first conductive layer 1d of the protection device that is the subject of the present invention. Is propagated by many reflections and absorptions, and as a result, radio waves can be considerably attenuated. In this way, the layers 1e and 1f form a 0.1 mm insulating layer. According to one variant, one or the other of the layers 1a or 1b has the reference number NWMP. 61027, which is a silver nonwoven fabric ISOWAVE manufactured by Schlegel BVA, or a graphite coating.

A protection device for an electrical circuit against MDI according to the object of the invention, more particularly applied to the protection of electromagnetic transducers, such as loudspeakers, in sound restoration devices for audio and / or video frequency recording. Another embodiment of is described below with reference to FIGS. 4a and 4b.

The loudspeaker is formed by a transition piece, represented by the symbol SH, having a pole gap E, as indicated by a cross section in some of the accompanying drawings. Within the barrel, a moving electric coil Co can be displaced, this moving electric coil being connected to a diaphragm M and an assembly thus formed comprising an audio and / or video frequency converter such as a loudspeaker. Is configured.

In such a case, the movable electric coil Co
Can be reliably protected from the MDI phenomenon. For this purpose, the device
As mentioned above, it is constituted by a protective coating formed by an electromagnetic-absorbing coating having the reference number 1a, and also, like the electromagnetic-absorbing coating denoted by the reference number 1b, heat is applied to the partition walls of the pole gap E. It is molded and, if necessary, also thermoformed, for example, on the diaphragm M, in particular in the vicinity of the moving electric coil Co.

Furthermore, the support of the movable electric coil Co can also be formed in this case by an electromagnetic absorbing coating with the reference number 1 in FIG. 4b.

As you know, the moving electric coil Co of the loudspeaker is subject to the vibrations it generates, and thus is a fairly important source of MDI phenomena.

If necessary, it is possible to cover a portion called a cone for tightening the diaphragm M. Regarding the transition piece SH, when the magnet used to construct the transition piece is not a conductor, for example, especially when it is made of ferrite, it can be similarly covered.

In the case of FIG. 4b, furthermore, when the support of the moving electric coil Co consists of an electromagnetic absorbing coating having the reference number 1, the diaphragm M itself also emits electrostatic charges which appear on the surface of the diaphragm M. And, as a result, it can be made of similar materials to improve the sound quality by Rabbeck effect.

In a variant of the embodiment, it has been shown that this diaphragm M can likewise be coated with a coating of a semiconductor product, such as the product BAYTRON mentioned above in this document.

The protection of vibrating devices such as electric motors or transformers used in audio and / or video frequency signal recording playback devices, in accordance with the objectives of the present invention, M
Another application of the protection device against the DI phenomenon is described below in connection with FIGS. 5a and 5b.

FIG. 5 a shows, for example, a drive motor for a reproduction medium, such as a compact disk, in a cross-sectional view, this motor being arranged in a conventional manner in one outer frame Ca with a stator winding Stat. , A rotor winding Ro, a stator connection wire and a stator supply wire AStat, and a rotor connection wire and a rotor supply wire Aro. The capstan can be driven by the transmission shaft, and the capstan itself drives the recording medium.

In such a case, the MDI phenomenon increases at a large rate by the triboelectric effect, ie, especially at the interface affected by vibrations in any electromagnetic and / or acoustic device. This is especially true in the case of transformers and motors which radiate disturbing electromagnetic energy from the outer surface of the winding.

As shown in FIG. 5 a, the protection device according to the invention comprises a protection element 1, which in this case surrounds the electric motor such that the encapsulation of the motor is achieved by said protection element. Can be thermoformed. In addition, the protective coating thus formed can be connected to ground by means of, but not limited to, a damping impedance RT. This attenuation impedance is, for example, 1.5 MΩ
And a ground inductance of 2.5 mH. Similarly, the supply cables of such motors are shielded under the conditions described later in this document.

With respect to the transformer, the phenomenon of disturbing radiation is similar to that described above, and the outer casing of the transformer shown in FIG. 5 is likewise shown in FIG. A protective element 1 constituting a seal can be provided. Such encapsulation can then be achieved by thermoforming in a similar manner.
Alternatively, a metal cloth ME can be superimposed on the encapsulation coating 1, which is then connected to ground by means of the damping impedance described above. FIG.
Although not shown, the same measures can be taken for transformer protection.

Another application of the protection device of the electric circuit against the phenomenon of MDI according to the object of the invention relates to the protection of electronic devices, in particular cabinets included in the construction of a set of high fidelity stereo devices.

Such an application is, on the one hand, a metal case as shown in FIG. 6a, on the other hand an electrically insulating cabinet as shown in FIG.
Regarding the input of cables in any type of case or cabinet, as shown in c.

In the case of a metal case, as shown in FIG. 6a, such a cabinet or case can be provided with a mobile audio and / or video frequency signal or data from an audio and / or video frequency recording medium driven by an electric motor. It is possible to house a playback device for reading the recording, i.e., a device for amplifying these audio and / or video frequency signals or data and a device for sound restoration,
The protection device for these electronic circuits against the MDI phenomenon comprises at least one protective coating with the reference number 1 formed by an electromagnetic absorbing coating, as described above in this document. As shown in a partially broken perspective view in FIG. 6a, the electromagnetic absorbing coating 1 is arranged on the inner side of the case. In the embodiment of FIG. 6a, the case is electrically conductive, so that the case is further connected to ground via the damping impedance RT. The interfacial micro-discharge phenomenon generated by the electric circuit portion housed in the cabinet can be prevented from being trapped by other electric circuit portions by the electromagnetic absorbing film 1, and the electromagnetic wave caused by such a discharge phenomenon can be prevented. Radio waves are significantly suppressed.

As shown in FIG. 6 b, in the case of an electrically insulated case or cabinet, in addition to the inner coating 1 as shown in the above drawing, a full or partial outer coating 1 ′ Is believed to be particularly advantageous because this outer coating removes any static charge present on the case surface. The case, for example,
When made of semiconductor such as carbon-filled plastic, this kind of case
In such a case, the outer coating can be eliminated, since the electrostatic charge is released, so that the MDI-type phenomena associated with this electrostatic charge can be eliminated.

With regard to the materials that can be used to realize the inner coating 1 or the outer coating 1 ′ described above, it has been shown that all of the several materials mentioned above in this document can be used. However, in an advantageous embodiment, the use of semiconductor films with the product BAYTRON from Bayer Chemie has been shown to give particularly meaningful results. Installation of the semiconductor film on the inner surface of the electrical insulation case
It was carried out by spraying the BAYTRON product in accordance with a film thickness not exceeding 10-20 μm.

Finally, a particularly advantageous application of the protective device, which is the subject of the present invention, relates to a wire entry which constitutes the entry of a cable in a case of insulation and / or conductor, as shown in FIG. 6c. Electromagnetic waves associated with the MDI phenomenon certainly propagate as surface waves to the insulator / air interface of the conductor. The use of such a wire passage can be carried out as follows. That is, when the case includes the case main body COF and the cover COU covering the case main body, the gap between the closed cover and the case main body is an electric wire passage for a cable such as a flat cable CP. This through-hole is, for example, as shown in cross section in FIG. 6c, with at least a flat cable CP and a coating of a flat cable having the reference number 1 formed of an electromagnetic absorbing coating. And a flexible joint JE enclosing the entirety of the flat cable CP and the sheath 1. With this flexible joint JE, the case body COF
Sealing between the cover and the cover COU can be ensured.

The electromagnetic waves associated with the interfacial microdischarge phenomena can thus be absorbed by the coating 1 in the case in its case at its entrance, so that the radiation level concerned can be reduced. When the flat cable CP is a cable marketed under the trademark FLATLINE, consisting of a copper tape laminated with a polytetrafluoroethylene coating, the wire entry described in connection with FIG. 6c is particularly advantageous. Seems to be.

Another particularly advantageous application of the protection device against MDI phenomena, in which the electric circuit is likely to be its source, is the case where this electric circuit constitutes a printed circuit board, with reference to FIGS. It is explained in.

FIG. 7a shows some elements that are substantially similar to FIG. 1 described above in this document. In particular, the printed circuit board PCB has a first side and a second side opposite to the first side, the first side having some elements mounted thereon. The second side includes a printed circuit and a metallization to which the element is connected.

In the case of the more specific embodiment shown in FIG. 7a, the protective device against interfacial microdischarge phenomena, which is the subject of the present invention, is a protective element comprising an electromagnetic absorbing coating as described above in this document. And this protection element has the reference number 1.

This protection element can be formed by a simple electromagnetic absorbing coating, as already shown in FIG. 1, on the upper part containing several elements, but on the lower part on the metal shielding side, by the electromagnetic absorbing coating 1 has reference number 1 _0, not only the electromagnetic absorption film in the original meaning, it is advantageous that it can also be constructed of the same metal shielding insulating material layer which is adhered to side 1 _2.

More specifically, a specific resistance small enough not to cause a short circuit of the metal shield and a proper flow of electric charge are ensured, and an interfacial discharge phenomenon and an electromagnetic wave propagation phenomenon accompanying this phenomenon are suppressed. a semiconductor material having a higher and a sufficiently large electrical conductivity decreases, the insulating material layer 1 ₂ has been shown to be indeed configured. In these conditions, the protective element 1 in the lower portion of the printed circuit board PCB shown in Figure 7a 'is formed by the protective coating 1 ₀ in the original sense insulating material layer, that is, the semiconductor layer 1 _2. For this layer, a layer or film of the product BAYTRON from Bayer Chemie can be produced by spraying, for example.

In addition to the structure shown in FIG. 7a,
A special printed circuit board which allows the installation of audio frequency elements in a device for audio and / or video frequency signal restoration and amplification, including a protection device according to the object of the invention, is described in connection with FIG. 7b. This is described below.

As shown in cross section in the above figure, the printed circuit board includes a basic printed circuit board PCB, which has a printed circuit-free printed circuit board corresponding to the upper surface of FIG. 7b. 1 and the second side facing said first side and including said printed circuit, ie this basic printed circuit board P shown in FIG.
There is a lower surface of the CB.

In addition, the printed circuit board that constitutes the protection device against the MDI phenomenon includes an electromagnetic-absorbing coating with the reference number 1 as described above in this document, this coating being the basic printed circuit board It is located on a first side of the PCB, the top side.

Finally, a substrate of electrically insulating material, also having first and second surfaces and designated by the reference IB, is overlaid on the electromagnetically absorbing coating 1. The second surface of the IB is disposed on the electromagnetic absorption coating 1. The assembly thus formed by the basic printed circuit board PCB, the electromagnetic absorbing coating 1 and the board IB forms a sandwich structure. In this sandwich structure, reference I
The insulating substrate marked with B is for housing the audio frequency element,
The second side of the basic printed circuit board PCB containing the printed circuits is provided for receiving the connections of the audio frequency elements to these printed circuits.
In this case, the electromagnetic absorbing coating 1 made of a metal cloth or a nonwoven fabric constituting the sandwich structure is laminated between the two substrates PCB and IB. Preferably, the substrates PCB and IB can be composed of polytetrafluoroethylene, a material that exhibits excellent resistance to interfacial microdischarge.

The sandwich structure thus obtained, as shown in FIG. 7b, is then stabilized by pressing or laminating, but in some cases ensuring the sintering of the polytetrafluoroethylene. To do so, it may be fired next. The assembly may further involve a coating of a semiconductor film made from the product BAYTRON described above in this document. The semiconductor film can be affixed to one side or the other side of the sandwich structure, ie, either the top or the bottom.

The film added to the upper surface of the sandwich structure has the reference number 1,
Thus, this last embodiment, corresponding to the semiconductor film added in the conditions described above, is shown in FIG. 7c. Similarly and in one advantageous embodiment, reference is made to a material of the same nature as the layer 1 'described above and to the layer 1' shown on the upper surface of the sandwich structure in FIG. With a layer or film of semiconductor material interposed therebetween, the upper surface of the basic printed circuit board PCB is separated from the electromagnetic absorbing coating 1, which itself forms the first basic printed circuit. It is shown that the circuit board PCB is separated from the insulating substrate IB. The layer 1 'of second semiconductor material is in this case a basic printed circuit board PC
B, and this upper surface is thus separated from the semiconductor absorbing coating 1. The assembly realized in this way can be subjected to the above-mentioned laminating and sintering processes.

A playback device for reading audio and / or video frequency signals from a recording medium for audio and / or video frequency signals or data, a device for amplifying these audio and / or video frequency signals or data, and a device for amplifying these audio and / or video frequency signals or data Another particularly notable application in a device for protection against interfacial microdischarge phenomena in electrical circuits according to the object of the present invention, in connection with a connecting cable in a sound restoration device for video frequency signals or data, is shown in FIGS. 8c will be described below.

In general, cables that may be equipped with protective devices in accordance with the objects of the present invention include almost any type of cable shown in FIGS. 8a and 8b, eg, having the properties of a coaxial cable. Cable or the trademark FLATL shown in FIG. 8c
It is shown that it can be a flat cable like INE.

In each case, the cable has on its peripheral surface a coating with the reference number 1 formed by an electromagnetic absorbing coating as described above in this document.

In the case of FIG. 8 a, a coaxial type cable is helically wound with an electromagnetic absorbing coating made of woven or non-woven material, as described above in this document. The absorbent coating is molded into a strip of predetermined length and cut. The helical winding is carried out so as to overlap the strips in order to ensure an overall superposition. The junctions of the overlapping strips can then be subjected to a spot welding step or similar to maintain the overall integrity.

In the case of FIG. 8b, the coating of the entire coaxial cable is carried out by winding the material longitudinally, folding it along the edge of the bus bar of the coaxial cable, and welding the two folded edges. You.

In the case of a flat cable as shown in FIG. 8c, the edges of the jacket are simply overlapped and fixed, for example, by welding.

In addition to the embodiment shown in FIGS. 8a to 8c for electrical or electronic cables, one particularly advantageous embodiment is to make the conductors themselves from metal cloth, if the overall resistance is sufficient. If it is small, it has been shown to be possible.

Finally, the bare conductors used for the implementation of the wiring or inductance in the circuit of the Hi-Fi playback device may also be formed by spiral windings or insulation, as described in connection with FIGS. Depending on the appropriate process, it is possible to coat with a metal cloth.

Another notable application of the protection device against MDI phenomena of electric circuits specific to the mode of propagation of electromagnetic waves associated with MDI phenomena is described below in connection with FIGS. 9a to 9h.

Due to the impulse-like nature of such MDI phenomena, noise and electromagnetic waves associated with these phenomena do occupy a frequency band whose lower limit is in the range of 0.1 to 10 GHz.

The filtering of the disturbance currents generated in this way is difficult since the conventional method using inductance or ferrite has little effect at about 1 GHz. Indeed, in the disturbing capacitance of the coil, the skin effect in the ferrite reduces any inductance effect from the critical frequency value most often corresponding to the low threshold value of the MDI phenomenon, ie approximately 1 GHz.

In order to reduce the above mentioned disadvantages, according to the object of the present invention, the M
A device for protection against the phenomenon of DI may likewise consist of constructing a protection circuit in its original sense, which is connected to the electrical circuit to be protected, from the electromagnetic absorbing coating described above in this document.

To this end, as shown in FIG. 9 a, the electromagnetic absorbing coating with the reference number 1 is in this case labeled with the input electrical connection Ci and with the reference Co. There is an advantage that an output electrical connection can be provided.

Under these conditions, the electromagnetic absorption coating 1, the input connection, and the output connection form a transmission line with a very low attenuation below the cutoff frequency of the transmission line, and a very high attenuation above this cutoff frequency. Is formed.

Of course, the absorption of electromagnetic waves associated with the MDI phenomenon is a function of the overall length of the transmission line thus formed, and in one preferred embodiment reduces the total volume of the components thus realized. At the same time, in order to reduce the ohmic resistance and to increase the length of the passage of the electromagnetic wave and the amount of absorption of the electromagnetic wave, there is an advantage that the electromagnetic absorption film 1 is wound in a stack.

The above components have the following properties in this case: Lack of internal noise capacitance as in the case of convolution when using classical self-inductance-between 4 × 10 ⁻⁶ Ω × m and 50 × 10 ⁻⁶ Ω × m Low skin effect caused by the large resistivity of the material used-operation similar to that of a dissipative transmission line with a very high attenuation due to the cut-off frequency of the transmission line FIG. 9b shows that the electromagnetic absorbing coating is Schlegel BVA 2 shows the transfer function of such a component when it is a silver woven fabric marketed by the company.

This transfer function, represented by the impedance / frequency logarithmic coordinates, characterizes the above components. In the frequency range from 0 kHz to 15 kHz, the abscissa is a scale representing frequency, the impedance of this component varies almost linearly in the numerical range from 0.024 ohm to 20 ohm, and the frequency of 15 MHz In the above, the increase in impedance of the above components is almost exponential with frequency.

In a preferred embodiment, shown in cross-section in FIG. 9c, these components are:
In order to form a substantially cylindrical element, such as a sleeve MA, it is constituted by overlapping wound bands, the input electrical connection Ci and the output electrical connection Co being provided at the opposite ends of said cylindrical element or sleeve. Each is formed.

To utilize this type of component, a 5 mm diameter coated with polymer conductor
It has been shown that winding can be accomplished using a band of woven or non-woven fabric sold by Schlegel BVA, a cloth of silver thread of μm.

The length of the strip or tape used for winding can vary from 1 m to 10 m, depending on the final resistance obtained.

The following table shows the approximate resistance values obtained depending on the length of the tape used.

Length (in meters) Resistance (in ohms) 2 0.035 4 0.015 10 0.005 The resistance values shown are the transmission line cutoff frequencies as shown in FIG. 9b. It corresponds to the measured resistance value.

Finally, the ends of the sleeve thus formed can be bound by copper or conductive wires to ensure the connection of the input and output connections described above.

The binding or the input / output connection has the advantage in this case that it can be protected by an encapsulating sheath with the reference signs Gi and Go.

[0135] Larger values of resistance can be obtained by utilizing shorter lengths of electromagnetic absorbing coating tape, or in some cases, placing several elements in series.

In accordance with the objects of the invention, but more particularly, it makes use of components which do not themselves emit or suppress electromagnetic interference. Another embodiment of the components forming the protection device is shown in FIG.
This will be described below with reference to

In FIG. 9d, substantially the same elements are found as in FIG. 9c, but these elements have the same reference numbers.

[0138] Input / output connection elements Ci, in addition to Co and sleeve MA, on behalf of the encapsulation sheath Go and output encapsulation sheath Gi of the input, in Figure 9d, the only with reference irradiation symbols G ₁ An encapsulating sheath can be used.
In addition, an electromagnetic absorbing coating 1 surrounding the encapsulating sheath G ₁ is provided, which, by means of the damping impedance, for example a ground potential, such as ground potential, as described above in this document. A connection is provided so as to enable connection of the electromagnetic absorbing film having the following.

In this case, a second encapsulation sheath G ₂ can also be installed, as shown in FIG. 9d, to ensure the integrity of the assembly and the protection of the electromagnetic absorbing coating 1. .

In general, it has been shown that the input / output encapsulation sheaths Gi, Go and the first and second encapsulation sheaths G ₁ , G ₂ can be made by heat-shrinkable sheaths.

With respect to the use of components as shown in FIG. 9a, and especially 9c, 9d, it has been shown that these components can advantageously be located at critical locations of the Hi-Fi playback device. . However, such a critical location is defined as a location that allows almost free propagation of electromagnetic waves accompanying the MDI phenomenon due to surface wave type propagation. Such critical points are, for example, as follows. -The input and output of the circuit;-the input point of the power supply to the electronic card;-the supply point of the local power grid, and in particular the supply cable to the supply power transformer;-the terminal of the local power grid cable;-very sensitive to high frequency disturbances. Feedback loops-Terminals of the loudspeakers in the speaker unit-Input and output terminals of the distribution filter of said speaker unit Such components are connected to the local distribution network cable in series with neutral and phase, of this type. Be subject to testing by introducing components. By utilizing these components, it is possible to perceive greater accuracy in the bass of audio signals transmitted by Hi-Fi devices supplied from such circuits, and this superior accuracy is further improved. High sound clarity over the entire audio frequency spectrum.

As with the amplifier, tests were repeated on the connection cable of the sound source, such as a tuner or an optical disc reader of the compact disc CD type, with similar results.

Finally, comparable tests were performed on the speaker unit terminals, but these components were connected in series with the loudspeaker supply wires and showed comparable effectiveness.

Referring to FIG. 9b, in the above components, the sudden increase in impedance above the cut-off frequency, occurring at a rate of 60 dB per octave, illustrates the effectiveness of filtering the electromagnetic waves associated with the MDI phenomenon. It is especially understood that there are.

[0145] In addition to the metal cloth described above in this document, the use of a gas containing semiconductor powder may also be used so that the overall conductivity of the assembly is sufficiently large for the use of the above components. It has been shown that it is possible to use a gas comprising a mixture of semiconductors consisting of conductive particles and insulating particles, and in some cases a powder or mixture of semiconductors.

The powder may be a powder of compressed graphite and a metal powder in air or in an insulating medium such as a semiconductive polymer.

[0147] Structures containing compressed graphite have been shown to be significantly closer to resistance in carbon aggregates having a reproducibility that is generally known among fellow audiophiles.

In addition, the overall structure obtained by utilizing such powders shows that the appearance is M
It is close to Branly's coherer structure, which is linked to the DI phenomenon.

The above test was carried out under the following conditions. -Reference number NWMP. Local power grid filtration performed by inserting two circuits as shown in FIG. 9c or 9d, made of silver-nickel cloth commercially available at 61027, one of which is: The other device is connected in series to the phase and the other device is connected in series at the neutral point and is connected to the spectrum analyzer. The device or component provides 30 dB of attenuation at 1.8 GHz. An apparatus consisting of two tubes containing graphite in compressed powder form: the apparatus is 27 mm in diameter, 50 mm in length, 0.1476 ohm and 0.62 ohm. The resulting attenuation is 32 dB at 1.8 GHz and the slope of the absorption is steeper,
Absorption peaks appear for some frequencies. The behavior of such components is close to that of Branly's coherer. -Components made of fine steel wool: quality 0000, length 75 mm
, And 25 mm in diameter, forming a sleeve. It showed very regular attenuation over the entire spectrum range from 0 to 1.8 GHz. A filter consisting of two components, each in neutral, in series in phase: these two components consist of one copper component and one silver-nickel component. Under such conditions, the attenuation is abrupt at high frequencies reaching 50 dB at 1.8 GHz, and is slow but regular up to 900 MHz. The damping obtained at the neutral point of the power supply cable, respectively, by means of a filter consisting of a copper component, a silver-nickel component and a steel wool component in series in phase. In this case, the attenuation obtained in the range from 58 dB to 1.8 GHz, which is very satisfactory and, moreover, the obtained curve is very regular.
Among these test configurations, several better listening tests were revealed.

The complete schematic of the filtration device used in the last case of the test described above is shown in FIG.
Is shown in

In this figure, PM represents a local distribution plug to be directly connected to the local distribution network, CCu represents a copper component as described above, and CAg-Ni represents a silver as described above. -Nickel component, and CFe represent the steel wool component described above. These three components are connected in series and, in the phase of the plug PM, are each connected at a neutral point and further connected to an outlet PF for constituting an output terminal connected to a spectrum analyzer. . In addition, the case or cabinet described above in this document and having the reference number CO, which is constituted by the material of the semiconductor, or, in some cases, the material which is an insulator but which is provided with an outer coating of the semiconductor, has a damping effect. The maintenance of the assembly, outer part or semiconductor case CO, which is connected to ground by a resistor, is realized.
The connection points of the components CCu, CAg-Ni and CFe themselves have a resistance R of several ohms.
And via a circuit of capacitance C having a value of 25 pF to the semiconductor case CO or the semiconductor coating of this case. The ground resistance RT is 1M
Ω and had been fitted with a Shafer-type filter with reference number RE1-16 / 4.

As for the resistance R, this resistance is provided by the filament of the low power vacuum sphere,
Thus, it is shown that a vacuum resistance free of the interfacial micro-discharge phenomenon was realized.
Finally, a semiconductor partition with the reference Cl can separate the filtering branch for the phase from the filtering branch for the neutral point.

In general, as mentioned earlier in this document, the effectiveness of filtration, and thus the absorption of electromagnetic waves associated with the interfacial microdischarge phenomenon, is described above in connection with FIGS. 9a to 9e. The length of the signal path in such a component or circuit.

A special, non-limiting embodiment that allows the length of the passage to be increased without unacceptably increasing the number of components is described below in connection with FIG. 9f. Is done.

As shown in a longitudinal section in the above figures, this component comprises a first component or circuit C ₁ and a second component C ₁ in addition to an outer sheath G made of an insulating material such as a heat-shrinkable material. it is an advantage that the component or circuit C ₂ of the can is installed. The two circuits are connected in series, but have a substantially cylindrical permanent magnet that generates a longitudinal excitation H according to the symmetric longitudinal axes of the _first and _second components C ₁ and C _2. Are physically separated from each other. Under these conditions, the magnetic field or the excitation produces a magnetron effect in the current, which no longer propagates according to a substantially straight line, but according to a circular trajectory having the axis of symmetry as the axis of symmetry.

Under these conditions, it is observed that the length of the passage is greatly increased, and as a result, the absorption of electromagnetic waves accompanying the MDI phenomenon can also be increased. The two circuits or components C ₁ , C ₂ as shown in FIG. 9f may be the same or different, depending on the embodiment described above with respect to FIG. 9e.
Each terminal of the sleeve is provided with a terminal sealing Sc.

A protection device for the above-mentioned phenomenon, which constitutes a type of filter having a resistance capacitance to electromagnetic waves accompanying the MDI phenomenon, will be described below with reference to FIGS. 9g and 9h.

[0158] As shown in FIG. 9 g, one of the device comprises a first cylindrical element having a reference numeral E _1, this element, some of the materials described above in this document To form a central core with input and output connections, represented by Ci ₁ and Co ₁ , respectively, which are wound in a stack of electromagnetic absorbing coatings.

In FIG. 9g, continuous, generally tubular elements, marked E ₂ , E ₃ , are likewise provided, which are continuously overlapping sleeves, as described above. As shown in FIG. 9g, tubular elements I ₁ , I _{2 of} electrical insulation,
A tubular element E ₂ , E ₃ formed by winding a tape of the electromagnetic absorbing coating forms an alternately formed sleeve. The tubular elements E ₂ and E ₃ are the tubular elements E ₁
It is made in the same way as. These elements are input connections Ci ₂ and Ci ₃ , respectively.
Further, output connections Co ₂ and Co ₃ are provided.

With the substantially cylindrical first element E ₁ , the continuous tubular elements E ₂ , E ₃ and the insulating tubular elements I ₁ , I ₂ , the assembly thus formed forms the first element E 1 _In the vertical cross section of ₁ and the continuous tubular elements I ₁ , E ₂ , I ₂ , E ₃ , each forms a continuous concentric circular area with the electromagnetic absorbing coating tape and the electrical insulation. The assembly of the these elements, the input connection Ci ₁ ~Ci ₃ and output connection Co ₁ to CO ₃ is thus formed a wave filter having a resistance-capacitance that enables the attenuation of electromagnetic waves associated with MDI phenomenon.

In accordance with the purpose of the present invention, an electrical schematic diagram corresponding to a device for protecting against interfacial microdischarge phenomena as shown in FIG. 9g is shown in FIG. 9h. that is,
This is a symmetric T-type filter composed of several T-type filter elements. The capacitance C shown in FIG. 9h is certainly a particular advantage, but it has been shown that if interfacial microdischarge occurs, it is immediately absorbed by the composition and therefore corresponds to a capacitance without microdischarge. I have.

Finally, the main application of the protection device of the electric circuit against the MDI phenomenon is described below with respect to a storage medium for audio and / or video frequency data, which is directly integrated into this medium. I have. According to the object of the present invention, M
The direct incorporation of the protection device of the electric circuit against the phenomenon of DI, of course, almost completely suppresses the generation and propagation of electromagnetic waves associated with the microdischarge phenomenon, and ultimately prevents the presence and appearance of the corresponding noise Depending on the extent to which this is possible, one will understand the particularly important nature of such applications.

This embodiment is particularly applicable to a recording / reproducing medium for optically read data, such as a compact disc CD. Such a recording medium provided with a protection device according to the object of the invention will be described below in connection with FIGS. 10a to 10e, wherein these figures show a compact disc with such a protection device. FIG. 2 shows a cross-sectional view of a CD-type recording medium in a radial plane.

In the above figures, the same reference symbols are, for example, the same elements as in FIG. 3b.

As shown in FIG. 10a, the recording / reproducing medium for optically read data comprises a metal disk or a metallization of the reference ME, which metallization corresponds to the reference C.
D ₀ of being constituted by a polycarbonate layer, it is shown that has been subjected to the recording / reproducing surface of the data. Indeed, the polycarbonate layer CD ₀ comprises a cut surface, which surface is metallized with metallization ME,
Cutting metal layer interface ME surface of the polycarbonate layer CD ₀ constitutes a reading surface CD ₁ of the recording medium CD. The metal disk surface or disk-shaped metallization ME facing the recording surface comprises a protective layer V of varnish and, if appropriate, silk screen printing.

According to a particularly advantageous characteristic of the optically read data recording / reproducing medium according to the object of the invention, the data recording / reproducing medium has a surface electrical resistance of between 0.004 ohm and 0.5 ohm per square. An electromagnetic-absorbing coating with the reference number 1 is applied, which is in the range This electromagnetic absorbing coating can attenuate MDI phenomena and noise associated with such phenomena. In FIG. 10a, this electromagnetic absorbing coating 1
Is placed on the protective varnish layer V and is shown to be fixed on this layer. Thus, as described above in this document, the electromagnetic absorbing coating 1 may consist of a layer of a semiconductor material, such as the material BAYTRON commercially available from Bayer Chemie.

In another non-limiting embodiment, as shown in FIG. 10b, an optically readable data recording / reproducing medium comprising a device according to the present invention comprises a transparent medium. includes an electromagnetic absorbing film 1 is composed of a film of a semiconductor material, the film, the polycarbonate layer CD _0, on the free surface of this layer CD _1, therefore, the recording / reproducing surface having the reference numerals CD ₁ They are formed facing each other.

In such an embodiment, it has been shown that the electromagnetic absorbing coating can be constituted by a film of the material BAYTRON, also commercially available from Bayer Chemie. The conditions for forming such a film will be described later in this document.

In one embodiment variant of an optically readable data recording / reproducing medium equipped with a device according to the invention, as shown in FIG. surface opposite to the surface CD _1, i.e. attached to the free surface of the varnish protective layer V, have been shown to be composed of at least one metal-coated conductive plastic film. In such an embodiment, the electromagnetic absorbing coating 1 of the metal-coated conductive plastic material is a plastic material commercially available from Sekisui Chemical under the trademark ELSON G406AS, ie, a 0.5 or 0.3 mm thick SOFT P
It has been shown that it can be a VC.

In one preferred non-limiting embodiment, the electromagnetic absorbing coating 1 constituted by a metal-coated plastic film, which is applied to the surface facing the recording / reproducing surface, ie on the free surface of the varnish protective layer V, , 10d, it may further include a coating layer of an electrical insulator material having the reference number 3. This layer of electrical insulator material 3
It is composed of a highly insulating synthetic foil with a thickness of 0.1 to 0.3 mm and is made of a material such as polyethylene. By placing the layer 3 of electrical insulator material over the layer 1 of metallized conductive plastic material, as shown at 10d, it is possible to actually prevent the propagation of electromagnetic waves associated with the MDI phenomenon. This electromagnetic wave is transmitted to a layer 1 of a metal-coated conductive plastic material, which layer absorbs the electromagnetic wave.

The improvement obtained by the use of a recording / reproducing device and a recording / reproducing surface medium according to the object of the present invention, as described in connection with FIG. 10d, can then enjoy an unparalleled listening experience. The more decisive.

Finally, in one specific, non-limiting embodiment, a special sandwich structure of multiple semiconductor layers, each serving the function of an electromagnetic absorbing coating, is used as shown in FIG. 10e. Can be

In this embodiment, on the one hand, the varnish protective layer V comprises, on its free side, like the embodiment of FIG. 10c, a layer 1 of semiconductor material, on the other hand,
The interface between the metallized ME and the polycarbonate layer CD ₀ , i.e. the cuts of this layer CD ₀ , is very similar to that of FIG. 10 c, to ensure that the reading surface CD ₁ shown therefor can be read. It is realized via a layer 1 of thin semiconductor material. Thus, 'in order to present, the layer 1' layer 1,1 of the two semiconductor material by, on the one hand, to ensure the reading of the reading surface CD _1, i.e., when the irradiation by the laser beam, polycarbonate layer It is possible to ensure that this laser beam is transmitted to the metallized ME by means of the cut surface and subsequently reflected by the metallized coating, and return to the playback device without apparent attenuation, on the other hand: The layer 1 ′ of the semiconductor material can suppress the micro-discharge phenomenon at the interface between the polycarbonate insulator and the metal coating and, as a result, the micro-discharge phenomenon that occurs when the read laser beam is excited.

One preferred embodiment of an optically readable data recording / reproducing medium, such as a CD, in which the electromagnetic absorbing coating forms a multilayer structure, is described below in connection with FIG. 10f.

In the above figure, the recording / reproducing medium according to the object of the present invention is laminated,
It includes a number of electromagnetic absorbing coatings, referenced 1a, 1b, 1c. The electromagnetic absorption coating is inserted between the varnish protection layer V that can constitute the layer 1c and the metal coating ME.

[0176] According to a particularly remarkable characteristic of the electromagnetic absorption coating, these electromagnetic absorbing coating, unique to increase gradually from the reading surface CD ₁ on opposite sides CD ₂ in physical contact with that contact electromagnetic absorbing film 1a Indicates electric resistance. In this case, the electromagnetic absorbing coating 1c is constituted by an epoxy varnish protective layer V, whose specific electric resistance ρd is greater than 10 ⁸ Ω × m, and fulfills the function of the final protective layer.

In one particular embodiment, the electromagnetic absorbing coating 1a in physical contact with the metallized ME is a reference CCP105 sold by Bayer Chemie.
A product from T. BAYTRON was composed of a layer of semiconductive polymer material. This layer after curing exhibited a thickness of 7 μm and a surface resistance of 10 ³ to 10 ⁴ per square.

The electromagnetic absorbing coating 1b, which is in physical contact with the electromagnetic absorbing coating 1a, has an approximately appropriate thickness, but after curing shows a surface resistance of 10 ⁸ to 10 ⁹ per unit square. The product BAYTRON consisted of a layer of semiconductive polymer material. The change in surface resistance, ie the tapering change, is obtained by dilution of the BAYTRON product and by adapting the resulting thickness. The process for producing a continuous layer of a multilayer structure is described below.

As described above with reference to FIGS. 10a to 10f, the manufacturing process of the recording / reproducing medium according to the object of the present invention is shown in FIG. from the test piece, a polycarbonate was injection-molded into a mold M, is deposited by metal deposition metallization ME on the cut surface in order to constitute a reading surface CD _1, then centrifuged coated onto the metal coating Depositing a protective varnish layer.

According to the process which is the subject of the present invention, a film of a semiconductor material, such as the material BAYTRON, is furthermore deposited on the varnish protective layer V.

In the art, a centrifugal coating operation, commonly referred to in the English language as a “spin coating” operation, comprises a cutting, comprising, on a rotary drive table TE, a layer of metallization with a varnish protective layer V. And placing the pressed presscake GG. Nozzle A
As shown in FIG. 11, the intestinal-packed semiconductor material BSC is spirally placed on the varnish protective layer V, near the center of the cut press cake GG, and then the drive table TE and the press. The cake GG is rotated at a slow speed, for example, no more than 4 or 5 revolutions per minute. When the intestinal semiconductor material BSC is formed, the nozzle A is closed and the drive table TE and the cut presscake GG are rapidly rotated at a speed exceeding 1500 rpm for 2 seconds. By the centrifugal force applied to the intestinal semiconductor material BSC, the intestinal semiconductor material BSC is spread in a uniform layer over the entire surface of the varnish protective layer V. When the intestinal semiconductor material BSC used is a polymer such as BAYTRON, a solidification process caused by reticulation by UV irradiation can be used.

According to a first variant of this step, the varnish protection layer V is directly replaced by a layer of semiconductor material.

In a second variant of the process, a layer of a semiconductor material, such as a BAYTRON material, is arranged on the non-cut free surface of the polycarbonate presscake GG. The attachment is performed by centrifugal coating.

In a third variant of the process, a film of semiconductor material is arranged at an intermediate stage prior to the metallization stage. The deposition is likewise effected by centrifugal coating.

In a fourth embodiment variant of this step, after or instead of depositing a film of semiconductor material on the varnish protective layer V, a layer of insulator material, ie FIG.
There is a deposition step of layer 3 shown in FIG.

It is specifically pointed out that in some of the above-described variants, the same process can be applied to the layer of metallized ME or to any suitable intermediate surface. In particular, to produce a multilayer electromagnetic absorbing coating as shown in FIG. 10f, as described in connection with FIG. 11, each layer of the electromagnetic absorbing coating, as described in FIG.
Can be made by centrifugal coating. To make layers from a semiconductor polymer material such as BAYTRON, each layer 1a,
1b can employ a solidification step by UV reticulation to create the next layer to be overlaid, as shown in FIG. 12b.

[Brief description of the drawings]

FIG. 1 shows a cross-sectional view of an electrical circuit protection device against interfacial microdischarge phenomena in accordance with the objects of the present invention.

FIG. 2a relates to an embodiment of a device for protecting an electric circuit against interfacial micro-discharge phenomena when the protective veil is made of non-woven fabric.

FIG. 2b relates to another embodiment of a device for protecting an electrical circuit against interfacial micro-discharge phenomena when the protective veil is made of woven fabric.

FIG. 2c relates to still another embodiment of a device for protecting an electric circuit against an interfacial micro-discharge phenomenon when a protective film is provided on a medium.

FIG. 3a more particularly relates to a specific embodiment of the device according to the object of the invention, applied for a recording medium reproduction system of audio frequency signals or data, such as a reproduction table of an LP record. It is.

FIG. 3b relates to a specific embodiment for a compact disc of the optical reading type, in which a protection device according to the object of the invention is applied.

FIG. 3c relates to a specific embodiment of a device similar to FIG. 3b, according to the object of the invention, which differs in that an assembly of conductive devices and conductive elements is included.

FIG. 3d shows a cross-sectional view of a multilayer electromagnetically absorbing veil disk, comprising first and second electromagnetically absorbing veil disks, according to the present invention.

FIG. 3e shows a cross-sectional view of a multi-layer composite electromagnetic absorbing veil disk comprising a plurality of electromagnetic absorbing veil, in accordance with the objectives of the present invention.

FIG. 3f shows a cross-sectional view of a multilayer composite electromagnetic absorbing veil disk including four nonwoven foil layers in accordance with the objectives of the present invention.

FIG. 4a relates more particularly to a special embodiment of the device according to the invention, applied for an electro-acoustic conversion system such as a loudspeaker used in a Hi-Fi stereo device.

FIG. 4b relates more particularly to another special embodiment of the device according to the object of the invention, applied for an electro-acoustic conversion system such as a loudspeaker used in a Hi-Fi stereo device. is there.

FIG. 5a more particularly applied in a hi-fi recording / reproducing apparatus for audio and / or video frequency signals, for protecting a drive motor in a reproduction table of an LP record or a compact disc or a capstan of a recording tape, It concerns a special embodiment of the device according to the object of the invention.

FIG. 5b more particularly relates to a special embodiment of the device according to the object of the invention, applied for protecting a transformer in a hi-fi recording / reproducing device for audio and / or video frequency signals. It is.

FIG. 6a shows one device for protecting an electrical circuit against interfacial micro-discharge phenomena according to the object of the invention, applied to a pluggable cabinet or case in an audio and / or video frequency signal recording / reproducing device. .

FIG. 6b shows another protection device for an electric circuit against interfacial micro-discharge phenomena according to the invention, applied to a pluggable cabinet or case in an audio and / or video frequency signal recording / reproducing device. Is shown.

FIG. 6c shows one application of the protection device, which is the subject of the present invention, with respect to a wire entry which forms the entry of a cable in a case of insulation and / or conductor.

7a, more particularly, when the electrical circuit is formed in the form of a printed circuit, the incorporation into the electrical circuit of the device according to the object of the invention significantly eliminates the interfacial microdischarge phenomenon. 1 shows a cross-sectional view of an electrical circuit protection device against interfacial micro-discharge phenomena according to the object of the present invention, applied to all types of electrical circuits, each composed of various printed circuits.

7b, more particularly, when the electrical circuit is formed in the form of a printed circuit, the incorporation in the electrical circuit of the device according to the object of the invention considerably eliminates the interfacial microdischarge phenomenon, FIG. 4 shows a cross-sectional view of another protection device of an electric circuit against interfacial micro-discharge phenomena according to the object of the present invention, applied to all types of electric circuits, each constructed from a special printed circuit.

7c more specifically, if the electrical circuit is formed in the form of a printed circuit, the incorporation of the device according to the invention into the electrical circuit considerably eliminates the interfacial microdischarge phenomenon, FIG. 3 shows a cross-sectional view of yet another protection device for an electrical circuit against interfacial microdischarge phenomena, according to the object of the present invention, applied to any type of electrical circuit, each composed of a special printed circuit.

FIG. 8a shows a cross-sectional view of one device for protecting against interfacial micro-discharge phenomena according to the present invention, applied to a connecting cable used in a Hi-Fi audio and / or video frequency device.

FIG. 8b shows a cross-sectional view of another protection device against interfacial micro-discharge phenomena applied to a connecting cable used in a Hi-Fi audio and / or video frequency device, in accordance with the object of the present invention.

FIG. 8c shows a cross-sectional view of yet another device for protecting against interfacial micro-discharge phenomena applied to a connecting cable used in a hi-fi audio and / or video frequency device, in accordance with the present invention.

FIG. 9a shows one of the protection devices against interfacial micro-discharge phenomena, implemented in the form of passive components that enable the electromagnetic waves associated with interfacial micro-discharge to be filtered and attenuated.

FIG. 9b is a graph showing the impedance, as a function of frequency, of a component as shown in FIG. 9a, when the component is being wound to form a sleeve.

FIG. 9c illustrates one embodiment of a wound configuration component that allows for filtering and attenuating electromagnetic waves associated with interfacial microdischarge phenomena.

FIG. 9d shows another embodiment of a component in rolled form that allows filtering and attenuating electromagnetic waves associated with interfacial microdischarge phenomena.

FIG. 9e is a diagram representing one application of a wound configuration component that allows for filtering and attenuating electromagnetic waves associated with interfacial microdischarge phenomena.

FIG. 9f illustrates yet another embodiment of a component in a rolled configuration that allows for filtering and attenuating electromagnetic waves associated with interfacial microdischarge phenomena.

FIG. 9g illustrates one embodiment, in a wound configuration, of one component exhibiting characteristics of a resistance capacitance filter for electromagnetic waves associated with the interfacial microdischarge phenomenon.

9h is an electrical equivalent diagram of the components shown in FIG. 9g.

FIG. 10a shows, in cross section, one of the optical recording / reproducing media for audio and / or video frequency digital data, provided with a protection device for the electrical circuit against the interfacial micro-discharge phenomenon, in accordance with the object of the present invention. is there. This type of audio and / or
Alternatively, in a digital data optical recording / reproducing medium for a video frequency signal, at the time of reproducing the digital data by the conventional reproducing apparatus, the interfacial microdischarge phenomenon and the noise accompanying these data are considerably removed at the source.

FIG. 10b shows another optical recording / reproducing medium for audio and / or video frequency digital data, similar to FIG. It is sectional drawing.

FIG. 10c is a cross-sectional view of one variation in an optical recording / reproducing medium for audio and / or video frequency digital data with a protection device for the electrical circuit against interfacial micro-discharge phenomena in accordance with the objects of the present invention.

FIG. 10d is a cross-sectional view of a preferred embodiment in an optical recording / reproducing medium for audio and / or video frequency digital data, provided with a protection device for the electrical circuit against interfacial microdischarge phenomena, in accordance with the object of the present invention. .

FIG. 10e is a cross-sectional view of one particular embodiment of an optical recording / reproducing medium for audio and / or video frequency digital data with a protection device for the electrical circuit against interfacial micro-discharge phenomena, in accordance with the object of the present invention. is there.

FIG. 10f is a cross-sectional view of one preferred embodiment of an optical recording / reproducing medium for audio and / or video frequency digital data, provided with a protection device for an electric circuit against interfacial microdischarge phenomena, in accordance with the object of the present invention. .

FIG. 11 shows by way of example various successive implementation steps in the process of manufacturing an optical recording / reproducing medium for audio and / or video frequency digital data according to the objects of the present invention.

FIG. 12a illustrates one variation for utilizing a multilayer electromagnetic absorbing coating in the process embodiment shown in FIG.

FIG. 12b illustrates another variation for utilizing a multilayer electromagnetic absorbing coating in the process embodiment shown in FIG.

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CR, CU, CZ, DE, DK, DM, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID , IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Invention Person Fontaine, Pierre France F-95220 Herbrelle du General de Gaulle 7 F term (reference) 5E321 AA21 BB23 BB41 BB44 GG09 GG11 5K052 AA02 BB23 DD28 FF35 FF38

Claims (33)

[Claims] 1. A device for protecting an electric circuit against an interfacial micro-discharge phenomenon which is a source of radio noise at an audio frequency, said device having at least one protection element formed of an electromagnetic absorbing film, Resistance is 0.00
A protective device for an electric circuit against interfacial micro-discharge phenomena which is in a range from 4 · 10 ⁻³ Ω × m to 5 · 10 ⁻³ Ω × m, wherein the electromagnetic absorbing coating can attenuate interfacial micro-discharge phenomena. 2. The apparatus according to claim 1, wherein said electromagnetic absorbing coating is constituted by a composition comprising organic fibers covered by a conductor coating. 3. The apparatus according to claim 1, wherein the electromagnetic absorbing film is made of an electromagnetic absorbing film. 4. A protection device against interfacial micro-discharge in a reproduction electric circuit of an audio and / or video frequency signal or data recording medium, wherein the signal and / or data from a rotating recording medium of audio and / or video frequency signals or data are provided. In a playback device for audio and / or video frequency recording for reading audio, the protection device comprises at least one electromagnetically absorbing coating disk according to any one of claims 1 to 3, wherein the electromagnetically absorbing coating disk and the A device for protection against interfacial micro-discharge phenomena in the reproduction electrical circuit of an audio and / or video frequency signal or data recording medium where the rotating recording medium is overlapping. 5. A device for protecting against an interfacial micro-discharge phenomenon in a reproduction electric circuit of an audio and / or video frequency signal or data recording medium, wherein said signal or data is read from a rotating recording medium of audio and / or video frequency signals or data. An audio and / or video frequency recording playback device for reading: a first electromagnetically absorbing coating disk according to claim 4; and a second electromagnetically absorbing coating superimposed on said first electromagnetically absorbing coating disk. A device for protecting against an interface micro-discharge phenomenon in a reproduction electric circuit of the recording medium for audio and / or video frequency signals or data, including a disk. 6. A protection device against an interfacial micro-discharge phenomenon in a reproduction electric circuit of an audio and / or video frequency signal or data recording medium, wherein the signal is transmitted from a rotating recording medium of audio and / or video frequency signals or data. Or in an audio and / or video frequency recording playback device for reading data, wherein the protection device comprises at least one electromagnetic-absorbing coated disc according to any one of claims 4 or 5; In a protection device against interfacial micro-discharge in a reproduction electric circuit of a signal or data recording medium, the protection device comprises several superposed electromagnetic absorbing films, each of which makes physical contact with the recording medium. From contact electromagnetic absorbing coatings to increase The outer electromagnetic absorbing coating opposite to the contact electromagnetic absorbing coating is substantially composed of a material of an electrical insulator, the interface micro-electrode in a reproduction electric circuit of an audio and / or video frequency signal or data recording medium. Protection device against discharge phenomenon. 7. A protection device against interfacial micro-discharge in a reproduction electric circuit of an audio and / or video frequency signal or data recording medium, wherein the signal or data is reproduced from a rotating recording medium of audio and / or video frequency signals or data. In an audio and / or video frequency recording playback device for reading audio and / or video frequency recording, said protection device comprises:-at least one electromagnetic-absorbing-coated disk according to any one of claims 4 to 6; A conductive device in electrical contact with the disk, the conductive device recording audio and / or video frequency signals or data enabling the discharge of static charge stored near the electromagnetic absorbing coating. Protection against interface micro-discharge phenomena in regenerative electrical circuits of media Location. 8. A device for protecting a movable coil against interfacial micro-discharge phenomena, comprising a transition piece having a magnetic pole gap and at least one loudspeaker formed by a movable electric coil connected to a diaphragm. In an audio and / or video frequency recording sound restoration device, the assembly of the transition piece provided with the pole gap, the movable electric coil, and the diaphragm forms a loudspeaker type audio frequency converter; 5. The protection device according to claim 1, wherein the partition wall of the magnetic pole gap of the transition piece and the partition wall of the diaphragm are thermoformed.
A protective device for a movable coil against an interfacial micro-discharge phenomenon, comprising at least one protective coating formed by the electromagnetic absorbing coating according to any one of the preceding claims. 9. The apparatus according to claim 8, wherein a support for the movable electric coil is formed by the electromagnetic absorbing coating. 10. A device for protecting against interfacial micro-discharge phenomena, which reproduces audio and / or video frequency recording by reading the signal or data from a movable audio and / or video frequency signal or data recording medium driven by an electric motor. In other words, in an amplifier and a sound restoration device for audio and / or video frequencies, each of which comprises one electric converter or transformer, the motor, the converter and the transformer are driven by the triboelectric effect. It is a source of mechanical vibration that tends to increase the interfacial micro-discharge phenomenon, wherein the protection device includes one protection element formed by the electromagnetic absorbing coating according to any one of claims 1 to 3, The protection device includes the motor, the converter, and the A device for protection against interfacial micro-discharge phenomena, which is thermoformed around the motor, the converter and the transformer, respectively, to effect encapsulation of the transformer. 11. A device for protecting an electronic circuit against interfacial micro-discharge phenomena, wherein audio and / or video frequency recording for reading a signal or data from a movable audio and / or video frequency signal or data recording medium driven by a motor. In the reproducing apparatus of the above, that is, the amplifying apparatus and the sound restoring apparatus for the signal or data of audio and / or video frequency, the reading apparatus for the amplification and the reading apparatus for the sound restoration are accommodated in a case forming both the apparatuses. At least one electronic circuit comprising at least one electronic circuit, the protective device being formed by an electromagnetic absorbing coating according to any one of the preceding claims.
A device for protecting an electronic circuit against interfacial micro-discharge phenomena, comprising: a protective coating, wherein the electromagnetic absorbing coating is disposed on an inner surface of the case. 12. The apparatus of claim 11, wherein the case is a case made of a conductive material, and the case is also electrically connected to ground via a damped impedance. 13. The protective case according to claim 1, wherein the case is a case made of an electrically insulating material, and the protective device is additionally formed by an electromagnetic absorbing film according to any one of claims 1 to 3. The apparatus according to claim 11, wherein the electromagnetic absorption coating is provided on an inner surface of the case. 14. The case includes a case main body and a cover for closing the case main body, and a gap between the closed cover and the case main body constitutes an electric wire passage for a flat cable, and the electric wire passage is provided. Is constituted by at least: the flat cable; and a coating of the flat cable formed by the electromagnetic absorbing coating according to any one of claims 1 to 3, and; 12. The apparatus of claim 11, comprising a flexible joint covering the assembly and ensuring a tight seal between the case body and the cover. 15. A device for protecting against interfacial micro-discharge phenomena, comprising: an audio and / or video frequency signal amplifying device and a sound restoring device having an audio and / or video frequency element installed on at least one printed circuit board. Wherein the printed circuit board includes a first surface on which the components are installed, and a second surface facing the first surface, wherein the second surface is connected to the plurality of components. A protection element formed by the electromagnetic absorbing coating according to any one of claims 1 to 3, and-the second surface of the printed circuit board. A layer of insulating material covering the assembly, the electromagnetic absorbing coating covering the assembly formed from the printed circuit board and the layer of insulating material. Forming a protection device to the interface micro-discharge phenomenon. 16. A printed circuit board for installing an audio frequency element in an audio and / or video frequency signal amplifying device and a sound restoring device, the printed circuit board comprising:-a first surface having no printed circuit; A first basic printed circuit board including a second surface facing the first surface and having a printed circuit; and being mounted on the first surface of the first basic printed circuit board. A second basic printed circuit board of an electrical insulating material having a first surface and a second surface, the electromagnetic absorbing coating according to any one of claims 1 to 3; The first surface of a second basic printed circuit board is disposed on the electromagnetic absorbing coating, the first basic printed circuit board, the electromagnetic absorbing coating, and the second basic printed circuit board Form an sandwich structure, wherein said second elementary printed circuit board of insulator material contains said audio frequency element, and said first elementary printed circuit board is comprised of said audio frequency element to said printed circuit. An audio and / or video frequency signal amplifying device and a sound reconstructing device, comprising: a second basic printed circuit board of an electrical insulator material having a first side and a second side adapted to receive a connection. Printed circuit board for installing audio frequency elements on the board. 17. The printed circuit board according to claim 16, wherein at least one of the two surfaces of the first or second basic printed circuit board comprises a film of a semiconductor material. 18. A connection cable for an audio and / or video frequency recording / reproducing apparatus for reading the audio or / video frequency signal or data from a recording medium for recording the audio or / video frequency signal or data, A connection cable for a data amplification device and a sound restoration device, wherein the cable has a coating formed on its peripheral surface by the electromagnetic absorption coating according to any one of claims 1 to 3. Or the connection cable of the video frequency recording playback device. 19. The electromagnetic absorbing coating has an input electrical connection and an output electrical connection, and the electromagnetic absorbing coating and the input electrical connection and the output electrical connection have a transmission line with a very small attenuation rate below its cutoff frequency. And a transmission line having a very high attenuation factor above its cut-off frequency. 20. A device for protecting against interfacial micro-discharge phenomena, wherein said electromagnetic absorbing coating is formed by a single tape wound over and over to form a substantially cylindrical element; 20. Apparatus according to claim 19, wherein output electrical connections are respectively formed at opposite ends of the cylindrical element. 21. A device for protecting an electrical circuit against interfacial micro-discharge phenomena, the device further comprising:-a first covering the assembly formed by the substantially cylindrical element and the input and output electrical connections. An encapsulation sheath, and an electromagnetic absorption coating according to any one of claims 1 to 3, surrounding the encapsulation sheath, the electromagnetic absorption being adapted to be electrically connected to a reference potential. 20. The apparatus of claim 19, comprising: a coating; and-a second encapsulating sheath surrounding the assembly formed by the electromagnetic absorbing coating and the first encapsulating sheath. 22. A device for protection against interfacial micro-discharge phenomena, wherein the device is formed by a single tape of an electromagnetic absorbing coating wound on top of one another and comprises an input electrical connection and an output electrical connection. A first cylindrical element forming a central nucleus;-a series of substantially tubular elements forming a series of overlapping sleeves, the sleeves being tubular of electrically insulating material; Element and claim 1
And a tubular element formed by winding the electromagnetic absorbing film according to any one of the above-described items, and is formed by the first element having a substantially cylindrical shape and the continuous element having a substantially tubular shape. The assembly includes a substantially circular continuous concentric area of an electromagnetic absorbing coating and an electrically insulating material, respectively, in a vertical cross-section of the first element, which is substantially cylindrical, and the substantially tubular continuous element. None, each of the sleeves, formed by a tubular element formed by winding an electromagnetic absorbing coating, is a resistance-
21. Apparatus according to any one of claims 19 or 20, including an input electrical connection and an output electrical connection to form a capacitance radio filter. 23. A recording / reproducing medium for optically readable data including a metal disk, wherein the recording / reproducing medium for optically readable data includes a recording / reproducing surface for the data which is coated with a polycarbonate layer. The surface of the metal disk opposite to the reproduction surface includes a varnish protection layer. In the optically read data recording / reproduction medium, the recording / reproduction medium has a specific electric resistance of 0.004 · 10 ⁻³ Ω × m
An optical reading data recording / reproducing medium comprising an electromagnetic absorbing coating in the range of from 5 to 5 · 10 ⁻³ Ω × m, wherein the electromagnetic absorbing coating can attenuate the interfacial microdischarge phenomenon. 24. The electromagnetic absorbing film faces the recording / reproducing surface,
24. The optically readable data recording / reproducing medium according to claim 23, comprising a film of a transparent semiconductor material formed on the polycarbonate layer. 25. The magnetic recording medium according to claim 23, wherein the electromagnetic absorbing film is made of at least one metal-coated plastic film stretched on the surface facing the recording / reproducing surface. An optically readable data recording-reproducing medium according to claim 1. 26. An optically readable data recording / reproducing medium according to claim 25, wherein the free surface of the metal-coated plastic film additionally has a coating of an electrically insulating material. 27. The optical recording / reproducing medium of claim 25, wherein the coating of the electrical insulator material is made of a material selected from polypropylene. 28. The data recording / reproducing medium further includes a plurality of superimposed electromagnetic absorbing coatings, each electromagnetic absorbing coating progressively increasing from a contact electromagnetic absorbing coating in physical contact with a surface opposite the reading surface. The outer electromagnetic absorbing coating opposite to the contact electromagnetic absorbing coating has an interface in a reproduction electrical circuit of an audio and / or video frequency signal or data recording medium, which is substantially composed of an electrically insulating material. Protection device against micro-discharge phenomenon. 29. A manufacturing process of a data recording / reproducing medium for optical reading of an optical disk CD type, wherein the data recording / reproducing medium is an electric circuit for an interface microdischarge phenomenon which is a source of radio frequency noise at an audio frequency. 29. The process for producing an optically readable data recording / reproducing medium according to any one of claims 23 to 28, comprising a protective device, the process comprising at least the following steps: a) from a cut test specimen. Molding the cut presscake by injection of polycarbonate; b) performing a metal coating on the cut surface of the presscake to form a reading surface of an optically read data recording-reproducing medium; c) depositing a varnish layer on the metallization; and d) a film of semiconductor material on the varnish layer. It consists of depositing, optical reading of the data recording - reproducing medium. 30. The process according to claim 29, wherein step c) is eliminated and step d) consisting of depositing a film of semiconductor material replaces step c). 31. The method of claim 29, wherein the step further comprises the step of depositing a film of semiconductor material on a non-cut surface of the cut press cake opposite the cut surface. The described steps. 32. The process further comprises a pre-step a ′) preceding the metal coating step b), said pre-step comprising applying a film of semiconductor material to the cut surface of the cut presscake; 32. The process according to any one of claims 29 or 31, wherein step b) of the metallization is performed on the film of the deposited semiconductor material after performing the preceding step. 33. The method according to claim 29, wherein after the step d) of depositing a film of semiconductor material on the varnish layer or instead of step c), a step of depositing a layer of insulator material is performed. Or the process of claim 1.