JP4314483B2 - Glass antenna tuning method and tuning tape used therefor - Google Patents

Description

  The present invention relates to a tuning tape used for tuning for optimizing an antenna pattern when designing a glass antenna formed on the surface of a vehicle window or the like, and a tuning method using the same.

  2. Description of the Related Art Conventionally, glass antennas that are formed of conductive metal-containing printed filaments on window glass plates for vehicles or buildings are known. In particular, glass antennas for AM broadcasting, FM broadcasting, or TV broadcasting provided on a glass plate of a rear window or a side window for a vehicle are widely used as a glass antenna for a vehicle.

  These glass antennas for vehicles are manufactured by printing a conductive metal-containing paste such as a silver-containing paste on the inside surface of a glass plate of a vehicle window by screen printing or the like and baking it. At that time, in order to obtain suitable antenna characteristics in the desired broadcast band, the optimum shape, optimum length, optimum spacing, etc. of each element constituting the antenna pattern are adjusted (tuned) based on the design values. There is a need to.

  In order to perform such tuning on a printed filament obtained by firing a silver-containing paste (hereinafter abbreviated as a silver-containing printed filament), if the silver-containing paste is fired each time, it takes too much time and is not practical. Therefore, conventionally, a copper foil tape having a width of about 1 mm and a thickness of about 35 μm is attached to a glass plate with an adhesive on the back surface to make a temporary antenna pattern, and the characteristics of this antenna pattern are investigated. Based on the results, the antenna pattern has been tuned by making several prototypes of the copper foil tape antenna pattern.

  However, there is a problem that a difference occurs in antenna characteristics between a glass antenna formed of a copper foil tape and a glass antenna actually composed of silver-containing printed wire provided on a glass plate of a vehicle window.

  For this reason, in the invention described in Japanese Patent Laid-Open No. 9-2324284 (Patent Document 1), attention is paid to the fact that the difference in antenna characteristics is caused by the difference in the resonance frequency due to the glass wavelength shortening rate. In order to change the numerical value of the glass wavelength shortening rate of the formed antenna pattern, it has been proposed to cover the tuning tape with a substance having a high dielectric constant.

  When tuning is performed using the tuning tape described in Patent Document 1, a dielectric paste or the like having a relative dielectric constant in the range of 3 to 14 is applied only to the tuning tape, or the upper portion of the tuning tape is covered with a resin sheet. . The thickness of a dielectric material such as a dielectric paste or a resin sheet is changed according to the width of the tuning tape, and a dielectric material having a thickness of about 2 mm at the maximum is used.

  However, the means described in Patent Document 1 has a problem that the tuning workability is remarkably impaired because the tuning tape is too thick. In addition, when an air layer (relative permittivity of 1) is interposed between the dielectric material and the tuning tape, the antenna characteristics are greatly changed due to the air layer, so that the antenna characteristics are not stable and the reproducibility is low.

  In order to solve such problems, Japanese Patent Application Laid-Open No. 2003-188622 (Patent Document 2) describes the tuning workability by making the electrical resistivity, line width, and line thickness of the tuning tape have a specific relationship. An improved tuning tape and tuning method are disclosed.

Japanese Patent Application Laid-Open No. 9-232846 JP 2003-188622 A

  However, even with the method disclosed in Patent Document 2, the tuning tape may not be able to reproduce the characteristics of the actual antenna pattern. In this case, the number of trials and errors of tuning increases, which takes time. Remains.

  The tuning tape of Patent Document 2 obtains equivalent antenna characteristics by matching electrical resistivity / (line width × line thickness) (hereinafter referred to as γ) with an actual antenna line. However, the present inventor has discovered that the antenna characteristics may be shifted even when γ is combined. This tendency is remarkable when the frequency becomes about 60 MHz or higher.

According to the inventor's knowledge, in Patent Document 2, since this is performed by thermal transfer that requires pressurization, it is not easy to control the width of the tuning tape, and the width is accurately formed over the entire length of the antenna wire. Because it is difficult.

In order to solve such problems, the present invention provides a tuning tape used for tuning a glass antenna having a resin particle-containing resin layer including a resin matrix and conductive particles mixed in the matrix. Therefore, the width of the tuning tape is formed with an accuracy of 0.1 mm or less with respect to the width of the antenna wire to be tuned , and conduction within the tuning tape matrix is ensured by shrinkage during resin matrix curing. A tuning tape is provided.

In particular, the tuning tape, a mixture of the resin and the conductive particles are formed on the transfer carrier sheet, absorbent, it is preferred that the matrix of the resin is curing shrinkage by heating. Moreover, it is preferable that dextrin paste is applied to the surface of the transfer mount, and the shape pattern of each element constituting the antenna pattern is formed on the mixture. It is preferable that two or more layers of the mixture are formed on a glass plate. Moreover, it is preferable that there is no pinhole of 50 micrometers or more. The surface roughness of the tuning tape, when formed on a glass plate, the center line surface roughness R _a, is preferably 1 to 5 [mu] m, to be capable of connection to an external circuit by further heating to the surface It is preferable to provide an antioxidant coating.

Further, the present invention relates to a tuning method for tuning using a tuning tape used for tuning a glass antenna provided with a resin particle-containing resin layer including a resin matrix and conductive particles mixed in the matrix. A step of mixing the resin and the conductive particles to obtain a mixture, a step of forming a pattern on the transfer mount with the mixture, and a step of separating the pattern from the transfer mount and transferring the pattern onto a glass plate; The tuning tape provides a glass antenna tuning method in which conduction in the matrix is ensured by shrinkage of the resin during matrix curing.
Further, the transfer board is a transfer board having water absorption and having a dequiltrin glue applied on the surface thereof, the step of immersing the transfer board on which the pattern of the mixture is formed in water and the pattern from the transfer board There is provided a glass antenna tuning method further comprising a step of sliding a glass plate onto a glass plate and a step of heating the glass plate. Moreover, the tuning method of the glass antenna further provided with the process in which the said mixture forms two or more layers on a glass plate is provided.
Moreover, the antenna characteristics of the temporary antenna are measured and compared with predetermined antenna characteristics by forming the above-mentioned tuning tape on the glass plate, and the antenna is based on the comparison result. A glass antenna tuning method for tuning an antenna pattern by modifying a pattern is provided.

  According to the present invention, it is possible to obtain a tuning tape and a tuning method capable of reproducing the characteristics of an actual antenna line very well and enabling efficient tuning. In particular, it can be applied to the tuning of glass antennas used in the frequency band of FM, AM, TV, keyless, GPS band 50 MHz to 2 GHz, satellite radio.

  In the present invention, first, the structure of the tuning tape is approximated to an actual antenna line. That is, in the present invention, a tuning tape including a conductive particle-containing resin layer including a resin matrix and conductive particles mixed in the matrix is used.

  When creating a real antenna wire, the silver paste is fired and the silver conductor is baked on the glass plate. The silver paste contains silver fine particles as a main component and a small amount of glass frit mixed therein. The glass frit is a binder between silver particles and serves to fix the silver particles on the glass plate. Since the silver conductor is baked on the glass in a short time, the particles having a particle size of 0.5 μm or less are slightly melted, and the particles are welded while leaving the shape of the large particles. It is done.

  On the other hand, the tuning tape of the present invention has a structure in which conductive particles are mixed in the resin matrix, and the conductive particles come into contact with each other due to shrinkage during curing of the resin matrix, and conduction in the resin matrix is taken. . That is, it is considered that the particle-shaped conductors are in contact with each other and have a capacity component between the silver particles and the silver particles.

  In the conventional tuning tape made of copper foil, the tuning tape is made of a single conductor and does not have a structure in which such particle-shaped conductors are in contact with each other. Although the detailed principle is unknown, it is presumed that the similarity of the structure is attributed to the fact that the tuning tape of the present invention has an antenna characteristic very close to that of an actual antenna line.

  The conceptual diagram of the cross-sectional structure of the tuning tape of the present invention is shown in FIG. The left is the state before the resin is cured, and the right is the state after the resin is cured. Before curing, the silver particles 4 and the resin 5 are provided in a mixed state on the glass plate 6, but the silver particles are close to the surface of the resin 5 layer due to shrinkage during curing and the surface tension of the resin. 4 comes into contact.

  In the present invention, the resin constituting the resin matrix for holding the conductor particles is not limited as long as it has lower electrical conductivity than the conductor particles and can hold the conductor particles, but the conductor particles are mixed in a normal state. It is preferably liquid so that it can be cured by applying energy such as heating or light irradiation. Moreover, what shrink | contracts at the time of hardening and strengthens the contact between conductor particles is preferable. From such a viewpoint, a thermosetting resin that shrinks upon curing is preferable. Examples of the thermosetting resin include those that are thermoset by being held at 150 ° C. for 60 minutes or by being held at 200 ° C. for 30 minutes. In addition, the resin is preferably chemically stable even if it contains metal powder, and more preferably one or more selected from the group consisting of epoxy resins, phenol resins and unsaturated polyester resins. preferable. As this thermosetting resin, it is particularly preferable to contain an epoxy resin which has excellent weather resistance after thermosetting and is easily available.

  The content of the resin with respect to the entire conductive particle-containing resin after curing is preferably 2 to 20% by mass, particularly preferably 5 to 15% by mass. If it is more than this, the conductivity will be lowered, and it may be difficult to match the characteristics with the actual antenna line, and if it is less than this, there is a possibility that the conductive particles cannot be retained.

  On the other hand, the conductive material forming the conductive particles is preferably a metal or an alloy, and in particular, silver, copper, gold, nickel, platinum, palladium, silver palladium, or the like can be used, but is not limited thereto. Silver is most preferable from the viewpoint of bringing the electrical characteristics closer to the actual antenna. The content is preferably 80 to 98% by mass, particularly preferably 85 to 95% by mass, based on the entire conductive particle-containing resin after curing.

  The diameter of the conductive particles is preferably 0.1 to 50 μm on a mass average. If it is larger than this, the screen mesh may be clogged and the printing accuracy may be lowered, and if it is smaller than this, the epoxy resin may enter between silver particles and the resistance value may be increased. As the shape of the conductive particles, a spherical shape or a flake shape is used. If it is flake-shaped, even if it is relatively large, the contact area can be increased, so that the electric resistance value can be lowered. In this case, the major axis is preferably 3 to 30 μm. Moreover, if it is a spherical shape, it is preferable to increase the area of a surface contact part by mixing a thing with a mass average diameter of 1-5 micrometers and a thing with a mass average diameter of 0.1 micrometer or less.

  The thickness of the conductive particle-containing resin layer in the tuning tape is preferably 10 μm or more after curing, and if it is more than that, it is not necessary to match the actual antenna. This means that the higher the frequency, the more transfer of charge occurs only on the surface of the conductor (skin effect), and if there is a thickness greater than the thickness where charge transfer occurs due to the skin effect, the antenna characteristics It is presumed that it will not be reluctant.

  In the present invention, the width of the tuning tape needs to be formed with an accuracy within 0.1 mm with respect to the width of the actual antenna line. As a real antenna, the range of the line width is usually 0.2 to 1.0 mm from the viewpoint of ease of manufacturing and not hindering the field of view, so that the tuning tape has the same width.

  Since the tuning tape is usually formed on a glass plate formed in the shape (curved surface) of an automobile window, it is necessary to carefully manage the tape width during the formation. In particular, unnecessary pressurization causes the tape width to change, so it is often better to avoid it.

  Equally important in managing the width of the tuning tape is the amount of pinholes in the tuning tape. The present inventors have discovered that the presence of pinholes in the tuning tape is important for stabilizing the properties of the tape. That is, if there is a pinhole, the width of the tuning tape is substantially changed, causing the antenna characteristics of the actual antenna and the tuning tape to deviate.

  In the present invention, the tuning tape preferably does not have a pinhole having a size of 50 μm or more. If there is a pinhole larger than this, the width of the tuning tape will change substantially, and it may be difficult to match the antenna characteristics with the actual antenna line.

In order to match the antenna characteristics of the tuning tape and the actual antenna, it is preferable to match the structure for expressing the conductivity. One index is the surface roughness of the tuning tape. Usually, the surface roughness of the actual antenna wire made of silver prints, the center line surface roughness R _a, is 1 to 5 [mu] m, as the tuning tape, when formed on a glass plate, the center line surface roughness R _a is preferably 1 to 5 μm.

  The tuning tape is preferably provided with an anti-oxidation coating. This coating is preferably made of an organic resin so that it can be connected to an external circuit by solder or the like without being peeled off from the tuning tape. For example, the coating is preferably made of acrylic resin, ethyl cellulose, alkyd resin, or the like. Moreover, it is preferable to set it as 10-50 micrometers as thickness.

  Since the tuning operation is performed on glass having the same shape as the actual window glass, it is necessary to form curved glass to form the tuning tape.

  First, a mixture of a resin serving as a matrix and conductive particles is applied on a glass plate in a predetermined pattern. As the construction method, a drawing method using a dispenser, a transfer method (dry type, wet type), an ink jet method, a laser method (preliminarily outputting a desired pattern from CAD data and drawing a glass frit-containing silver paste with a dispenser. And a method in which an excess glass frit-containing silver paste other than the conductor is washed off with water after being baked to a desired width with a laser beam. After application, the tuning tape can be formed on the glass plate by curing the resin through steps such as heating and light irradiation. Then, antenna performance is measured and necessary pattern adjustment is performed. In the present invention, the time for forming the tuning tape on the glass plate may be relatively short, and the matching of characteristics with the actual antenna is very good, so that efficient pattern tuning can be performed.

  When applying a mixture of resin and conductive particles on a glass plate, it is preferable to print twice or more in order to remove pinholes. In the case of using transfer, the mixture is previously formed by printing two or more layers on the transfer paper, and then transferred. According to the findings of the present inventor, the antenna characteristics are not substantially affected by the thickness of the tuning tape, while the influence of the pinhole is enormous. From this viewpoint, a mixture of resin and conductive particles is multilayered. The effect of forming is very large.

  Hereinafter, embodiments will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of the glass antenna of this embodiment. In the example of FIG. 1, an antenna pattern 2 and a feeding point 3 having an approximate length of 7000 mm are formed on an automotive window glass plate 1 having an approximate length of 520 mm and a width of approximately 750 mm.

  As the antenna pattern 2, a standard silver-containing printed wire, a copper foil tape (Example 4) as a conventional example, a tuning tape (Example 1) as an example, and a pin whose apparent width is the same as that of Example 1 but 50 μm or more A tuning tape (Example 2) that has been confirmed to have a hole, and a tuning tape (Example 3) in which a portion having a width of 0.4 mm different from that of the reference pattern is 0.7 mm in contrast to the width of the reference pattern is 0.7 mm. Using each, antenna pattern 2 was formed and four kinds of glass antennas were created.

  In the tuning tapes of Examples 1, 2 and 3, the layer of the mixture of resin and conductive particles formed on the transfer film was applied to a glass plate according to the method described in JP-A-59-101623. A desired antenna pattern is formed by transferring. For this reason, in Example 1, Example 2, and Example 3, there is no adhesive between the mixture and the glass plate.

  The antenna pattern 2 on the glass thus obtained is heated at a low temperature for a certain time to thermally cure the thermosetting resin contained in the conductive resin paste layer, thereby obtaining a conductive resin layer.

  Hereinafter, creation of the antenna pattern 2 using the tuning tape in Examples 1, 2, and 3 will be described more specifically. 10 parts by mass (hereinafter, simply referred to as part) of an epoxy resin that is thermoset by heating to 200 ° C. for 60 minutes, 75 parts of flaky silver powder having a mass average particle size of 3 to 30 μm, and spherical silver having a diameter of 0.1 μm A mixture of 5 parts of powder and 20 parts of organic resin was kneaded to obtain a mixture of resin and conductive particles. Here, the organic resin is obtained by kneading a mixture of 50 parts of an epoxy resin, which is a thermosetting resin, and 50 parts of ethyl cellulose.

  A dextrin paste was applied to water-absorbing base paper to form a transfer mount, and the mixture was printed on a 200-mesh stainless screen. An antioxidant coating having the following composition was formed on the printed surface to obtain a transfer paper.

  The transfer paper was immersed in water, the mount was separated from the printed portion, the printed portion was slid off to the desired portion of the glass plate, and dried at 50 ° C. for 10 minutes. Then, it heated at 200 degreeC for 60 minutes, the resin was hardened, and the tuning tape was formed. Table 1 shows the thickness and width of the conductor (conductive particle-containing resin layer) after the tuning tape is cured.

  Table 1 shows the results of various numerical measurements such as the dimensions and electric resistivity of the antenna pattern 2. Note that the number of pinholes refers to the number of pinholes existing in a 1 cm long tuning tape.

  FIG. 2 shows the received voltage-frequency characteristics at 70 to 90 MHz of the glass antennas of the reference and Examples 1 and 4 among the above, and FIG. 3 shows the reference and the glass antennas of Examples 1 to 3 at 91 to 755 MHz of the above. The received voltage-frequency characteristics are shown.

  In Example 1, the matching of the antenna characteristics between the tuning tape and the actual antenna line is good, and the tuning efficiency is high.

  The present invention can be used for tuning for optimizing an antenna pattern when designing a glass antenna formed on the surface of a vehicle window or the like.

The figure which shows the structure of the glass antenna of a present Example Reference, graph showing received voltage-frequency characteristics at 70 to 90 MHz of the glass antennas of Examples 1 and 4 The graph which shows the received voltage-frequency characteristic in 91-755 MHz of the reference | standard and the glass antenna of Examples 1-3. Conceptual diagram of the cross-sectional structure in the tuning tape of the present invention

Explanation of symbols

1: Glass plate 2: Antenna pattern 3: Feeding point 4: Silver particles 5: Resin 6: Glass plate

Claims (10)

A tuning tape used for tuning of a glass antenna provided with a resin particle-containing resin layer including a resin matrix and conductive particles mixed in the matrix,
Tuning the tape width is formed within an accuracy of 0.1mm with respect to the width of the antenna wire to be tuned,
A tuning tape characterized in that conduction in the matrix of the tuning tape is ensured by shrinkage during curing of the resin matrix . 2. The tuning tape according to claim 1, wherein a mixture of the resin and the conductive particles is formed on a transfer board having water absorption, and the resin matrix is cured and contracted by heating. The tuning tape according to claim 1 or 2, wherein a dextrin paste is applied to a surface of the transfer mount, and a shape pattern of each element constituting an antenna pattern is formed on the mixture. The tuning tape according to any one of claims 1 to 3, wherein the mixture is formed by stacking two or more layers on a glass plate, and the tuning tape does not have a pinhole having a size of 50 µm or more. The tuning tape according to any one of claims 1 to 4 , wherein the tuning tape has _a surface roughness Ra of 1 to 5 µm when formed on a glass plate. The tuning tape according to any one of claims 1 to 5 , further comprising an anti-oxidation coating on the surface that enables connection to an external circuit by heating . In a tuning method for tuning using a tuning tape used for tuning a glass antenna having a resin particle-containing resin layer including a resin matrix and conductive particles mixed in the matrix,
Mixing the resin and the conductive particles to obtain a mixture;
Forming a pattern on the transfer mount with the mixture; and
Separating the pattern from the transfer mount and transferring the pattern onto a glass plate,
The tuning tape is a tuning method for a glass antenna in which conduction in the matrix is ensured by shrinkage of the resin during curing of the matrix. The transfer board is a transfer board having water absorbency and having a dequiltrin glue applied to the surface,
Immersing the transfer board on which the pattern of the mixture is formed in water;
A step of sliding and transferring the pattern from the transfer mount to a glass plate;
Heating the glass plate;
The glass antenna tuning method according to claim 7 further provided. Forming a mixture of two or more layers on the glass plate;
Furthermore, the tuning method of the glass antenna of Claim 7 or 8 provided. The tuning tape as the temporary antenna by forming on a glass plate, as compared to the antenna characteristics predetermined by measuring the antenna characteristics of the temporary antenna, modify the antenna pattern based on the result of the comparison The tuning method of the glass antenna of any one of Claims 7-9 which performs tuning of an antenna pattern by doing.

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