JP4915059B2 - Electromagnetic wave suppressing material and electronic device - Google Patents

Description

  The present invention relates to an electromagnetic wave suppressing material used for measures against unnecessary radiation generated from an electronic device, and an electronic device including the electromagnetic wave suppressing material.

  With the increase in the use of high-frequency electromagnetic waves seen in recent years, damages and obstacles such as malfunction of equipment due to electromagnetic noise and adverse effects on the brain and human body have been raised as new environmental problems.

  For example, looking at the 2.45 GHz band, which is one of the frequency bands that do not require a license and can be used for wireless communication, this is a wireless LAN (IEEE802.11b), Bluetooth, ISM (Industrial, Scientific and Medical). ) It is widely used in equipment, etc. Furthermore, with the increase in the clock frequency and digitization of information equipment, the generation of harmonics in this band is also conceivable.

  In this way, the number and diversity of both potential electromagnetic wave sources and interference victims increase exponentially, increasing the risk of interference.

  In order to deal with such electromagnetic interference (EMI) problems, individual devices do not emit unnecessary electromagnetic waves that interfere with the normal operation of other devices (suppression of emissions). In addition, it is required to have sufficient strength (improvement of immunity) that is not affected by electromagnetic waves entering from the outside. Such a concept is referred to as electromagnetic compatibility (EMC), and various standards are established for electronic devices to establish electromagnetic compatibility in an electromagnetic environment.

  For example, when advancing EMC countermeasures in circuit design, an interference suppression element is mainly used as a circuit element for reducing electromagnetic interference generated from electronic equipment and preventing electromagnetic interference from entering electronic equipment. It is done.

  There are various types of interference suppression elements such as an LC filter and a varistor in which capacitors and coils are combined. They are designed to have a low loss when the desired signal passes through the device, and have a large reflection loss and passage loss for the interfering wave, and are combined in an appropriate manner in most electronic circuits. in use.

  However, the voltage or current waveform may vibrate due to a specific resonance frequency in combination with the circuit element, and the desired signal waveform may be greatly distorted. Further, the wavelength of the electromagnetic wave in the GHz band is close to the circuit length of the electronic circuit, and the circuit itself acts as an antenna for the electromagnetic wave, which may cause a malfunction.

  In this way, EMC problems that cannot be compensated for by circuit design have been raised at the stage of mounting design, but recently, as a solution, attention has been paid to mixing magnetic powder and resin into a sheet. The electromagnetic wave suppressing material or the electromagnetic wave absorbing material (hereinafter, these may be described as the electromagnetic wave suppressing material).

  The principle of electromagnetic wave suppression absorption in this electromagnetic wave suppression material is that most of the incident electromagnetic wave energy is converted into thermal energy inside the electromagnetic wave suppression material. For this reason, in the electromagnetic wave suppression material, both the energy reflected on the front surface and the energy transmitted to the rear can be reduced.

Here, the mechanism of conversion into thermal energy is mainly classified into three types: conduction loss, dielectric loss, and magnetic loss. The electromagnetic wave absorption energy P [W / m ³ ] per unit volume at this time is expressed by the following formula (1) using the external electric field E, the magnetic field H, and the frequency f of the electromagnetic wave. In this equation, the first term represents the conduction loss, the second term represents the dielectric loss, and the third term represents the magnetic loss.

〔但し、電磁波抑制材の導電率：σ
電磁波抑制材の複素誘電率：ε＝ε’−jε”（jε”は電磁波吸収の遅れ成分）
電磁波抑制材の複素透磁率：μ＝μ’−jμ”（jμ”は電磁波吸収の遅れ成分）〕

[However, conductivity of electromagnetic wave suppressing material: σ
Complex permittivity of electromagnetic wave suppression material: ε = ε '-jε "(jε" is an electromagnetic wave absorption delay component)
Complex permeability of electromagnetic wave suppression material: μ = μ'-jμ "(jμ is a delay component of electromagnetic wave absorption)

  Here, the mechanism of the conductive loss is that when an electric field is applied to a finite medium having a conductivity σ of the electromagnetic wave suppressing material, a conductive current flows and the energy of the electromagnetic wave is converted into heat. As the conductive loss material used for such a conductive loss, for example, a cloth in which conductive fibers are woven into a cloth shape, a dielectric sheet in which indium tin oxide is deposited, or the like is used. As a dielectric loss material used for dielectric loss, for example, a rubber sheet mixed with carbon particles, graphite-containing foamed polystyrene, carbon-containing foamed urethane, or the like is used. In addition, ferrite or the like is mainly used as a magnetic loss material used for magnetic loss.

  A conventional electromagnetic wave suppression material used for a transmission path or the like is considered to be a combination of a filter effect utilizing an inductor component peculiar to a magnetic material and the above-described electromagnetic wave absorption effect.

  Currently, a magnetic sheet used as an electromagnetic wave suppressing material is used by being attached to the upper surface of a printed circuit board, the upper portion of a flexible printed circuit (FPC), the back surface of a housing, the upper surface of a package, and the like.

  However, what effect appears by what principle is clarified because it differs depending on the complicated signal transmission path in the electronic device and the distribution of electric field and magnetic field created by itself. This is difficult.

  As described above, since the characteristics and effects of the magnetic sheet are not clear, the performance evaluation of the magnetic sheet is mainly performed by the high frequency filter effect (suppression effect) in the microstrip line and the above formula (1). Many estimates are made based on the magnitude of the loss term (ε ″, μ ″).

  On the other hand, FIG. 12A shows an example of an electromagnetic wave suppressing material using a medium with a high dielectric constant (see Patent Document 1 described later). The structure of the electromagnetic wave absorbing material 51a is a plate-like case 54. In the space partitioned by the provided partition walls, a mixture obtained by mixing the particulate ferromagnetic material 52 with the liquid medium 53 having a high dielectric constant is disposed.

  This is an electromagnetic wave suppressing / absorbing material in which the fine ferromagnetic material 52 is uniformly dispersed in a liquid medium 53 having a high dielectric constant such as water, glycerin or methyl alcohol.

  FIG. 12B shows another example of the electromagnetic wave suppressing material (see Patent Document 2 described later). The electromagnetic wave absorbing material 51b includes a heat transfer conversion layer 57 and a plurality of electromagnetic waves and electromagnetic waves. The electromagnetic wave absorbing layers 56a, 56b, and 56c are laminated electromagnetic wave suppressing materials that are alternately bonded via a plurality of easy-adhesive layers 55. The material of the electromagnetic wave absorbing layers 56a, 56b, and 56c contains rare earth ions A fixed medium in which an inclusion is dispersed or mixed in a resin is used.

JP-A 64-52302 (page 2, lower right column, line 1 to page 3, lower left column, line 7, FIG. 1) JP 2002-84089 A (page 4, left column, line 5 to page 6, left column, line 19, line 1)

  However, in the countermeasure against unnecessary radiation of the electronic device as described above, first, as expected, when the magnetic sheet is used by being attached to the upper part of the printed circuit board or the like, particularly the upper part of the IC package or the back surface of the housing. However, there is often a phenomenon in which the electromagnetic wave absorption effect is not obtained, and conversely, the electromagnetic wave absorption effect is decreased by increasing the magnetic field strength (amplifying the magnetic field on the exit side).

  In order to overcome such a current situation, an electromagnetic wave suppression sheet having better electromagnetic wave absorption characteristics than the existing magnetic sheet is required. In the existing magnetic sheet, the mixing amount of the magnetic powder is increased in order to enhance the characteristics. However, the specific gravity of the magnetic sheet increases with the increase in the amount of the magnetic powder, so that the magnetic sheet becomes a hard magnetic sheet.

  Therefore, for example, when affixing to the upper part of a flexible printed circuit (FPC), a more flexible electromagnetic wave suppression sheet is necessary to make use of the flexible characteristics, but a hard magnetic sheet is difficult to cope with. Furthermore, since magnetic powder is used, it becomes a high-cost magnetic sheet, and a cheaper electromagnetic wave suppression sheet is required.

  As described above, magnetic materials are still mainstream as electromagnetic wave suppression materials in the high frequency band. That is, the magnetic sheet using the magnetic material is designed so that the complex permeability μ ″ of the third term, which is the magnetic loss of the above formula (1), is high in order to suppress and absorb electromagnetic waves.

  Further, when a medium such as water is used, the characteristics are likely to deteriorate due to volatilization (or evaporation), and the durability and reliability are poor.

  That is, in the electromagnetic wave suppressing material shown in FIG. 12A, the particulate ferromagnetic material 52 and the liquid medium 53 having a high dielectric constant such as water, glycerin, or methyl alcohol are mixed. In the case of using a material containing water, it is impossible to completely prevent volatilization and leakage of moisture with respect to the reliability of maintaining characteristics for several years or more than 10 years, and a difficult technique is required for the prevention. It becomes. In addition, since the electromagnetic wave suppressing material contains moisture and the like, it is necessary to add a technique for preventing volatilization or leakage of moisture or the like to the laminate material. Need to increase.

  In addition, in the electromagnetic wave suppressing material shown in FIG. 12 (B), since the rare earth ion-containing clathrate is dispersed or mixed in the resin, in order to increase the electromagnetic wave absorbing ability, It is necessary to increase the amount of dispersion or mixing. Accordingly, the above example is the same, but in order to increase the electromagnetic wave absorbing ability, the overall weight and size are increased, and the shape followability (flexibility or flexibility) is poor.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electromagnetic wave suppressing material having flexibility and high density, having high durability and reliability, and the use thereof. Is to provide the electronic equipment that was.

  That is, this invention relates to the electromagnetic wave suppression material which consists only of an ionic liquid substantially. Here, “substantially” means not only 100% of the ionic liquid but may contain a small amount of additive components (hereinafter the same).

  The present invention also relates to an electromagnetic wave suppressing material, which is a gel material substantially containing only the ionic liquid, such as impregnating only the ionic liquid into the polymer network.

  The present invention also relates to an electronic apparatus in which the electromagnetic wave suppressing material is arranged at least one of an internal electromagnetic wave generation site and an external electromagnetic wave action site.

  In the process of devising the present invention, the present inventor paid attention to a material having a high dielectric constant ε ″ of the second term, which is a dielectric loss, in the frequency of the MHz band and the GHz band from the above formula (1). .

  Generally known solid ferroelectrics such as barium titanate show a high dielectric constant as the name suggests, but because the resonance phenomenon exists at low frequencies, dielectrics in the MHz and GHz band frequencies. It has almost no dispersion characteristic of the rate, and the value of the dielectric constant ε ″ is low. For this reason, magnetic materials are still the mainstream as electromagnetic wave suppression materials in the high frequency band so far.

  On the other hand, the present inventor has focused on the dielectric constant of a liquid material having ions such as an electrolytic solution, and found an electromagnetic wave suppressing material having high electromagnetic wave absorption efficiency.

The electrolytic solution containing these ions causes ionic conduction in accordance with the applied electric field. Although this ionic conduction depends on the type of solvent and the like, there is always a resistance component unless it is a superconducting material, and the ionic conductivity is governed by the size of the resistance component. It is considered that this resistance component corresponds to the loss part ε ″ of the relative dielectric constant. A value obtained by normalizing the dielectric constant ε of the material with the dielectric constant ε ₀ of the vacuum is referred to as a relative dielectric constant ε _r (= ε / ε ₀ ). The magnitude of the loss part ε _r ″ of the relative permittivity of the electrolytic solution containing ions has a value of several tens to several hundreds or more at 1 GHz or less. That is, the electrolytic solution containing ions can also absorb and absorb the energy of incident electromagnetic waves into Joule heat.

  However, a material containing moisture such as an electrolyte cannot completely prevent volatilization or leakage of moisture with respect to the reliability of maintaining characteristics for several years or more than 10 years. Difficult technology is required. In addition, a technique for preventing volatilization or leakage of moisture must be added to the laminate of the electromagnetic wave suppression material.

  On the other hand, according to the present invention, since the electromagnetic wave suppressing material is substantially composed of only the ionic liquid, or is a gel-like material having substantially only the ionic liquid, flexibility is achieved. In addition to being able to follow various shapes, the material is made of ionic liquid alone, so it can be formed at high density and no medium is required, so it has excellent electromagnetic wave absorption and may cause evaporation of moisture, etc. And high durability and reliability, and is relatively easy to fabricate. Thereby, an electromagnetic wave suppressing material having a high efficiency and a sufficient electromagnetic wave suppressing effect can be obtained.

  Moreover, since the electromagnetic wave suppressing material is provided in at least one of an internal electromagnetic wave generation site and an external electromagnetic wave action site, it is useful for EMC countermeasures that solve the problem of electromagnetic wave radiation and intrusion. Electronic devices can be provided.

  In the present invention, it is desirable that the ionic liquid is sealed with a sealing material such as a sealing film in order to improve the shape retention of the ionic liquid.

  Further, according to the arrangement state of the ionic liquid, the ionic liquid is formed in a sheet shape or a bulk shape in a state where the ionic liquid is sealed with the sealing material, or in a single state or a gel state. desirable.

  In addition, a laminate made of an insulating material may be applied to protect the ionic liquid.

  Further, the ionic liquid is composed of a cation and an anion, and the cation is composed of at least one selected from the group consisting of an aromatic group and an aliphatic quaternary ammonium salt group, and the anion includes Desirably, it comprises at least one selected from the group consisting of inorganic ionic and fluorine-containing organic anionic systems.

  The electromagnetic wave suppressing material may be provided on the integrated circuit element or the wiring in at least one of the internal electromagnetic wave generation site and the external electromagnetic wave operation site, or a plurality of wirings It is preferable to be sandwiched between the boards or between the wiring board and the housing.

  Next, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 11 show an embodiment of the present invention.

  FIG. 1 shows various electromagnetic wave suppression (absorption) materials 20 according to the present invention. These electromagnetic wave suppression materials have the ionic liquid material 1 which is an electromagnetic wave suppression material which consists only of the ionic liquid comprised with the ionic substance, or the gel material which hold | maintained only the ionic liquid.

  As a form of the electromagnetic wave suppressing material 20, for example, as shown in FIG. 1A, the ionic liquid material 1 can be used alone in a sheet form or the like.

  Further, as shown in FIG. 1B, in order to sufficiently maintain the shape of the ionic liquid material 1, the ionic liquid material 1 is preferably wrapped (sealed) with a film 2 (sealing material). . The film 2 may be a film-like container having an electromagnetic wave absorption property or a film-like container having no electromagnetic wave absorption property, but an aluminum foil or the like that reflects electromagnetic waves should be avoided.

  Further, the electromagnetic wave suppressing material 20 made of the ionic liquid material 1 can be formed in a sheet shape or a bulk shape in accordance with the arrangement state of the ionic liquid material 1. This may be a state where the ionic liquid material 1 is molded alone or a state where it is wrapped with a film 2 (sealing material).

  Further, as shown in FIG. 1C, in order to protect the ionic liquid material 1 disposed on the substrate 4, the ionic liquid material 1 can be covered with a laminate material 3 made of an insulating material.

  By using this ionic liquid material 1, ion conduction occurs in the ionic liquid material 1 due to the action of electromagnetic waves, and Joule heat is generated by collision of ions generated thereby, so that electromagnetic wave suppression and absorption amount increase. . In particular, the characteristic of a boiling point (or decomposition point) of −20 ° C. (freezing point) to several 100 ° C. fully expresses the non-volatility and stability of the ionic liquid material 1.

  Further, the ionic liquid material 1 is characterized by non-volatility, incombustibility, thermal stability, chemical stability (the ions do not react with other components and hardly change over time), high ionic conductivity, and electric polarization. It is resistant.

  FIG. 2 shows chemical components of the ionic liquid, which is composed of a cation and an anion. On the cation (cation) component side, 1-ethyl-3-methylimidazolium shown in FIG. An imidazolium salt system such as (EMI), an aromatic system such as a pyridinium salt system such as 3-butylpyridinium (BP) shown in FIG. 2B, a trimethylhexylammonium (TMHA) shown in FIG. Aliphatic quaternary ammonium salt systems, and aliphatic cyclic ammonium salt systems such as 5-membered ethylmethylpyrrolidinium (P12) are used.

In addition, on the anion (anion) component X ⁻ side, from an inorganic ion system such as bromide ion (Br ⁻ ), tetrafluoroporate (BF ₄ ⁻ ), hexafluorophosphoric acid (PF ₆ ⁻ ), pisttrifluoromethyl A combination of fluorine-containing organic anions such as sulfonic imide (TFSI), CF ₃ SO ₂ ⁻ , perfluorosulfonimide ((CF ₃ SO ₂ ) ₂ N ⁻ : TFSI) is generally used. The form is not limited to these.

  Alternatively, a polymer network such as polyacrylamide swollen (impregnated) with an ionic liquid or plasticized may be used as an ionic gel (gel-like material holding an ionic liquid). Since the ionic liquid and the polymer are very compatible with each other, the ionic liquid and the polymer are stable and difficult to separate, and various ratios of ionic gels can be prepared. Ion gel has a high dielectric constant, and has flexibility, transparency and self-supporting property. Moreover, when it is made compatible with the polymer, crystallization is suppressed, and a decrease in conductivity can be prevented.

  As described above, the ionic liquid material 1 that is the electromagnetic wave suppressing material according to the present embodiment pays attention to the high dielectric constant ε ″ in the above formula (1). In view of this, the present inventor verified the electromagnetic wave suppression effect of a typical electromagnetic wave suppression material focused on the dielectric constant.

  FIG. 3 shows a measurement method for evaluating the performance of the ionic liquid material 1.

  As shown in FIG. 3A, a linear microstrip line 5 is formed at the center of a substrate 6 having a ground potential conductive layer 7 on the back surface, and a part of the microstrip line 5 is covered. Thus, the ionic liquid material 1 used as a sample is arranged. The ionic liquid material 1 is in a sealed state as shown in FIG. 1B, but the sealing film is not shown (the same applies hereinafter).

As shown in FIGS. 3A and 3B, the substrate 6 has, for example, a relative permittivity ε _r of 4.1 and a width W × depth L × thickness T ₁ of 100.0 mm × 100. 0.0 mm × 1.5 mm.

The width W × depth L × thickness T ₂ of the conductive layer 7 is, for example, 100.0 mm × 100.0 mm × 0.018 mm.

  The width w × depth L × thickness t of the microstrip line 5 is 3.0 mm × 100.0 mm × 0.018 mm.

  Then, an input (IN) terminal 9a and an output (OUT) terminal 9b are formed at the respective end portions of the linear microstrip line 5, and the input terminal wiring 14a and the output terminal wiring 9b are connected to each other. The input terminal 9a and the network analyzer 8 and the output terminal 9b and the network analyzer 8 are electrically connected.

  Thereafter, a reflection characteristic and a transmission characteristic are measured by inputting a signal from the input (IN) side to the output (OUT) side of the microstrip line 5. The network analyzer 8 is used for the measurement, and the harmonic filter (shielding) effect of the sample is evaluated from the measurement result of the signal characteristics with and without the sample 1 at that time.

  Examples of the ionic liquid material 1 that is a measurement sample include 1-ethyl-3-methylimidazolium (EMI) as a cation and bistrifluoromethylsulfonylimide (TFSI) as an anion. The liquid material 1 is synthesized, sealed with a film, formed into a sheet, and fixed in place.

  4 to 5 are graphs in which the harmonic filter effect is evaluated using the electromagnetic wave suppressing material according to the present embodiment. For example, the measurement results of the reflection amount in the frequency range of 50 MHz to 1500 MHz (the required absorption performance of electromagnetic waves is particularly the frequency range of 30 MHz to 1500 MHz) are shown.

  The thin line is the measurement result under the condition without the sample (absorber), the solid line is the measurement result under the condition using the ionic liquid material 1 according to the present embodiment, and the broken line is commercially available as an electromagnetic wave suppression sheet. It is a measurement result on the conditions using the magnetic sheet (The thing (Brand name: Busta Raid (made by NEC TOKIN)) which bind | concluded sendust (Fe-Al-Si) powder with resin.

  FIG. 4 shows reflection characteristics (S11 characteristics) that are reflected when a signal is input to the input (IN) side of the microstrip line 5. The vertical axis represents the reflection amount (dB) and the horizontal axis represents the frequency (MHz). ).

  From FIG. 4, in the frequency range of 50 MHz to about 1000 MHz, the reflectivity when using the gel-like material (ionic liquid material 1) indicated by a thick line is in the range of −20 dB to −10 dB, particularly about −10 dB. It shows the characteristics of the same or slightly lower reflectivity than before and after using the conventional magnetic sheet indicated by a broken line. Further, the reflectance without the sample (without the absorber) indicated by the thin line is in the range of −60 dB to −20 dB, and particularly greatly increases and decreases in the range of −30 dB to −40 dB.

  Here, the reflectance of −30 dB is a mismatch between the input port and the impedance of the microstrip line model with respect to the signal (100%) input to the input side of the microstrip line 5, and the impedance of the sample is not set. For the sake of matching, this means that the reflectance of the signal reflected to the input side is 0.1%.

  From FIG. 4, in the frequency range of 50 MHz to about 1000 MHz, the reflectance when using the ionic liquid material 1 is similar to the reflectance when using the magnetic sheet, and there is no sample (no absorber). It is higher than the reflectance at 10% (reflectance). However, in this case, since the signal that is not reflected is 90%, it can be said that there is substantially no problem in terms of electromagnetic wave suppression and absorption effects.

  FIG. 5 shows a transmission characteristic (S21 characteristic) through which a signal is transmitted when a signal is input to the input side of the microstrip line 5, a vertical axis indicates a transmission amount (dB), and a horizontal axis indicates a frequency (MHz).

  From FIG. 5, in the frequency range of 50 MHz to about 1000 MHz, the transmission amount when using the ionic liquid material 1 indicated by the thick line is the transmission amount when using the magnetic sheet indicated by the broken line and no sample indicated by the thin line ( It can be said that it has a higher filter effect because the transmission amount is less than the transmission amount without the absorber) and the transmission amount is small.

  FIG. 6 shows the absorption characteristics (loss characteristics) absorbed by the sample when a signal is input to the input side of the microstrip line 5, the vertical axis indicates the loss rate (relative value), and the horizontal axis indicates the frequency (MHz). Show. The amount obtained by subtracting the reflection amount corresponding to FIG. 4 and the transmission amount corresponding to FIG. 5 from the input amount is the loss amount. The larger the loss amount, the greater the electromagnetic wave suppression and absorption effect.

  From FIG. 6, in the frequency range of 50 MHz to about 1000 MHz (particularly about 800 MHz), the loss amount when using the ionic liquid material 1 indicated by the thick line is the loss amount when using the NaCl aqueous solution indicated by the alternate long and short dash line. The loss amount when the magnetic sheet indicated by the broken line is used exceeds the loss amount without the sample (without the absorber) indicated by the thin line. In addition, about the sample of NaCl aqueous solution, the example shown by Japanese Patent Application No. 2005-136560 which this applicant has already proposed is represented for reference.

  From the measurement results of FIG. 6, the ionic liquid material 1 using dielectric loss is superior in electromagnetic wave suppression and in a frequency range of 50 MHz to about 1000 MHz, particularly 800 Hz or less, than a commercially available magnetic sheet using magnetic loss. It can be seen that it has an absorption effect.

  In addition, the ionic liquid material 1 according to the present embodiment has a light specific gravity and excellent flexibility as compared with an existing magnetic sheet.

  In addition, since the material is a single material (that is, no medium is required), the concentration can be 100%, and the electromagnetic wave suppressing material can be produced at a high density. Even if the thickness is reduced, the electromagnetic wave absorption efficiency is increased, and there is no problem of volatilization of a medium such as moisture, and the durability is excellent. Moreover, the production is relatively easy.

  Furthermore, since this ionic liquid material 1 has flexibility, it is rich in shape followability and flexibility. For example, a flexible sheet-like body such as a resin film that transmits electromagnetic waves, or a flexible bag-like body. It can be sealed (or packed) with any sealing material such as a hard case or a housing. Therefore, there is an advantage over the existing one in that there is no limitation of the characteristics depending on the shape from the bulk shape to the sheet shape.

  In addition, since the ionic liquid material 1 has a high boiling point of several hundred degrees C. and a freezing point as low as -20 degrees C., the operating temperature range when applied to a device is wide and the reliability is high.

  Thus, the electromagnetic wave absorption and suppression effect of the ionic liquid or the gel material holding the ionic liquid according to the present embodiment is highly efficient, and the influence of the electromagnetic wave from the electronic device (or on the electronic device) is minimized. It can be suppressed, and is useful as an EMC countermeasure product having flexibility and ensuring high durability and reliability.

  As a result, the unnecessary radiation countermeasure cost can be drastically reduced, and the countermeasure time can be reduced due to high efficiency.

  In addition, since it has flexibility compared to existing magnetic materials, it can be simplified in terms of mounting and can be used in a wide range of applications.

  Furthermore, since it is in the form of a gel, it can be placed between the substrates or between the substrate and the housing, and as a new material and device having both functions of electromagnetic wave suppression and absorption material and shock absorbing material Can be used.

  Next, FIGS. 7 to 11 show examples in which the ionic liquid material 1 is applied to an electronic device.

  FIG. 7 shows a handy camera 10 having a built-in board A (printed wiring board) 11A on which electronic parts are mounted and board B (printed wiring board) 11B on which electronic parts are mounted, and further comprising a monitor screen 12. Show.

  In this handy camera 10, the ionic liquid material 1 (or electromagnetic wave suppressing material) is, for example, as shown in FIG. 8, a flexible wiring board on which a wiring 14 for electrically connecting an A substrate 11A and a B substrate 11B is formed. The ionic liquid sealed with the film 2 in order to arrange it in a state where it is sandwiched and to be attached to the upper surface of an IC chip (integrated circuit element) 16 mounted on each substrate. Material 1 can be used.

  9 includes a B board (printed wiring board) 11B on which electronic components are mounted and a C board (printed wiring board) 11C on which electronic components are mounted, and further includes a housing 13 and a monitor screen 12. A handy camera 10 is shown.

  As shown in FIG. 10A, for example, when the C substrate 11C is arranged in the vicinity of the B substrate 11B, the mounting surface of the B substrate 11B and the non-mounting of the C substrate 11C are performed as shown in FIG. It is possible to fill and sandwich only the ionic liquid material 1 (that is, without a sealing material) in the gap with the surface. Further, as shown in FIG. 10C, the gap between the mounting surface of the B substrate 11B and the mounting surface of the C substrate 11C can be filled with only the ionic liquid material 1 and sandwiched. At this time, the ionic liquid material 1 to be arranged may be alone, or may be sealed with the film 2. In the case of a single product, it is in the form of a gel and can be easily filled in the gap, and can follow the shape of the mounting surface and the like, and is effective for bonding the two substrates.

  Further, as shown in FIG. 11A, for example, when the housing 13 exists in the vicinity of the C substrate 11C, the mounting surface of the C substrate 11C and the housing 13 are disposed as shown in FIG. The ionic liquid material 1 can be held in the gap. Also at this time, the ionic liquid material 1 to be arranged may be a raw material or may be sealed with the film 2.

  In this way, by providing the ionic liquid material 1 at least one of the internal electromagnetic wave generation site and the external electromagnetic wave operation site, the influence of the electromagnetic wave on the electronic device (or from the electronic device). Can be minimized.

  As mentioned above, although this invention was demonstrated based on embodiment, it cannot be overemphasized that this invention is not limited to these examples at all, and can be suitably changed in the range which does not deviate from the main point of invention.

  The electromagnetic wave suppression material and electronic device of the present invention can be applied to electromagnetic wave countermeasures for electronic devices.

It is the perspective view (A), sectional drawing (B), and another sectional drawing (C) of the ionic liquid material by embodiment of this invention. Similarly, chemical formulas (A), (B), and (C) of the ionic liquid material. FIG. 2 is a perspective view (A), a cross-sectional view (B) showing the structure of the measuring device for ionic liquid material, and a perspective view (C) showing the arrangement of the measuring device. It is a graph which shows the reflective characteristic by the correlation with the amount of reflection, and a frequency similarly. It is a graph which shows the transmission characteristic by correlation with a transmission amount and a frequency similarly. It is a graph which shows the absorption characteristic by the correlation of loss amount and a frequency similarly. It is a perspective view of an electronic device. It is a perspective view which shows the example of arrangement | positioning of an ionic liquid material similarly. It is a perspective view of an electronic device. FIG. 6 is a perspective view (A), a cross-sectional view (B), and a cross-sectional view (C) of another example showing an arrangement example of the ionic liquid material. It is the perspective view (A) and sectional drawing (B) which show the example of arrangement | positioning of an ionic liquid material equally. It is sectional drawing (A) of the electromagnetic wave absorber by a prior art example, and sectional drawing (B) of another example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Ionic liquid material, 2 ... Film, 3 ... Laminate material, 4, 6 ... Substrate,
5 ... microstrip line, 7 ... conductive layer, 8 ... network analyzer,
9a, 9b ... terminal, 10 ... handy camera, 11A ... A board (printed wiring board),
11B ... B board (printed wiring board), 11C ... C board (printed wiring board),
12 ... monitor screen, 13 ... flexible wiring board, 14 ... wiring, 15 ... housing,
16 ... Integrated circuit chip, 20 ... Electromagnetic wave suppression material

Claims (7)

Only the ionic liquid Ri is Na sealed with a plug, wherein the ionic liquid is formed by the cations and anions, the group the cation is composed of aromatic and aliphatic quaternary ammonium salt more consists of at least one selected, the anions, the inorganic ionic and fluorine-containing ing at least one selected from the group consisting of organic anionic, electromagnetic wave suppressing material. It is formed of a gel-like material made of polyacrylamide having only an ionic liquid, the ionic liquid is composed of a cation and an anion, and the cation is composed of an aromatic system and an aliphatic quaternary ammonium salt system. An electromagnetic wave suppressing material comprising at least one selected from the group consisting of at least one selected from the group consisting of inorganic ions and fluorine-containing organic anions.
  The electromagnetic wave suppressing material according to claim 1, wherein the electromagnetic wave suppressing material is formed in a sheet shape or a bulk shape. The only ionic liquids are sealed with a film or laminate material, electromagnetic wave suppressing material according to claim 1. An electronic device in which the electromagnetic wave suppressing material according to any one of claims 1 to 4 is provided in at least one of an internal electromagnetic wave generation site and an external electromagnetic wave action site. The electronic device according to claim 5 , wherein the electromagnetic wave suppressing material is provided on an integrated circuit element or wiring. The electronic device according to claim 5 , wherein the electromagnetic wave suppressing material is sandwiched between a plurality of wiring boards or between a wiring board and a housing.

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