1. Field of the Invention
The present invention relates to an antenna-embedded laminated glass with an antenna element sealed between glass sheets.
2. Description of the Related Art
Heretofore, an antenna sheet, which includes a conductive strip for an antenna element and an adhesive layer disposed on a base sheet as disclosed in e.g. JP-A-2001-119219, has been known. This antenna sheet can function as a glass antenna by being bonded to a surface of a glass sheet through the adhesive layer.
Such an antenna sheet is affixed to a surface of a glass sheet in use. From this viewpoint, when such an antenna sheet is bonded to, e.g., an interior surface of the front windshield of a vehicle, the conductive strip needs to be covered with a transparent protective layer. The protective layer is disposed for the purpose of preventing the conductive strip from being damaged and being disconnected by an external force. In some cases, a boundary line between the protective layer and the glass sheet with the antenna sheet affixed thereto is visible since the protective layer has a different refractive index from the glass sheet, and the protective layer covers the glass sheet over a relatively wide area. For these reasons, such an antenna sheet has a problem of poor appearance and a problem of obstructing a driver's view.
On the other hand, in an antenna-embedded laminated glass with an antenna element sealed between glass sheets as disclosed in e.g. JP-A-2-82701, an antenna element is protected by the glass sheets. Even when such an antenna-embedded laminated glass is applied to an automobile windshield, there is no problem, such as a poor appearance caused by the provision of a protective layer in a region except for the provision of the antenna element.
Such an antenna-embedded laminated glass is classified into a print type wherein conductive paste is printed in a desired pattern on an inner surface (mating surface) of a glass sheet to form an antenna element, and an intermediate film embedded type wherein an antenna wire is embedded in an intermediate film (typically made of polyvinyl butyral) interposed between glass sheets.
The above-mentioned print type cannot solve the problems of a poor appearance or the like since an antenna pattern needs to have a wide line width in order to ensure desired antenna performance because of the presence of large wire resistance.
In this regard, the above-mentioned intermediate film embedded type is advantageous from the viewpoint of appearance or the like since an antenna wire having a small diameter can be embedded in an intermediate film.
Such a glass antenna can be properly tuned so as to receive a desired electromagnetic wave in a target frequency band by comparing various patterns, such as disposing antenna-forming strips in a T-character shape or a cross shape. However, in the above-mentioned intermediate film embedded type with an antenna wire embedded in an intermediate film, when disposing antenna-forming strips are disposed in a T-character pattern or a cross shape, the intersection parts of the antenna-forming strips bank up in comparison with the remaining parts of the antenna-forming strips since the antenna-forming strips are formed of wires or the like.
Laminated glass is produced by interposing an intermediate film between two glass sheets, followed by press-bonding and heat treatment. Such an antenna-embedded laminated glass has had a problem of being defective as a laminated glass since gaps are formed between the intermediate film and parts of the two glass sheets corresponding to the intersections of antenna wires to prevent the intermediate film and the glass sheets from being brought into close contact even in a heat treatment process, such as press-bonding. For this reason, the above-mentioned intermediate film embedded type cannot be formed in such a shape to intersect antenna elements and has a limited tuning performance even if an attempt is made to have an increased antenna sensitivity.
From this point of view, it is an object of the present invention to provide an antenna-embedded laminated glass, which includes antenna elements formed so as to intersect each other.
In order to solve the above-mentioned object, the present invention provides an antenna-embedded laminated glass including a plurality of glass sheets affixed together through an intermediate film to embed an antenna element between adjacent glass sheets, the intermediate film containing a resin; and the antenna element being configured to have such a shape as to have an intersection where a plurality of antenna-forming strips intersect, and the antenna element comprising a conductor strip stamped in such a shape from a sheet-like conductor.
In the present invention, the conductor strip may have a boding strip laminated thereon, and the bonding strip may be affixed to a surface of at least one of the glass sheets that confronts the intermediate film. The bonding strip may be affixed to a convex side of the at least one of the glass sheets.
The conductor strip may have a boding strip laminated thereon, and the bonding strip may be affixed to a surface of the intermediate film.
The conductive strip may have a dark strip laminated on a surface thereof opposite from the bonding strip.
The antenna-embedded laminated glass may include an electrode for taking out a signal, disposed on an outermost glass sheet among the glass sheets; and the antenna element may be coupled to the electrode through static capacitive coupling.
In accordance with the present invention, by stamping a sheet-like conductor to form a conductor strip forming an antenna element, it is possible to provide a laminated glass wherein the antenna element is formed in such a pattern shape that antenna-forming strips intersect in a T-character shape or a cross shape.
In the drawings:
Now, preferred embodiments of the present invention will be described, referring to the accompanying drawings.
The laminated glass 10 is produced by press-bonding a plurality of glass sheets 12 with an intermediate film 14 interposed therebetween (see
Glass sheets 12 forming the laminated glass 10 have an antenna element 20 sealed therebetween as stated later. The antenna element 20 may be formed in a desired pattern as shown in
As shown in
In the glass sheets forming process 100, two basic glass sheets are independently subjected to cutting and chamfering steps (Step 101), and cleaning and drying steps (Step 102). In order to conceal an eyesore, a print is applied to an edge portion of the basic glass sheet (interior glass sheet) that forms the glass sheet 12b on the interior side of the two basic glass sheets (Step 103). The print may be applied to an edge portion of the exterior glass sheet 12a or may be applied to each of the exterior glass sheet and the interior glass sheet. After that, both glass sheets are overlapped with each other (Step 104), and both glass sheets have edge portions carried on a frame, being overlapped each other. Next, the glass sheets thus overlapped are heated to a temperature of not lower than the softening point and are bent in a curved shape by gravity (Step 105). Then, both sheets are subjected to annealing (Step 106), and both sheets are separated from each other (Step 107). Thus, the glass sheets 12a and 12b are provided with surfaces having substantially the same curvatures as each other. The glass sheets 12a and 12b are subsequently and independently subjected to washing and drying steps (Step 108) and are transferred into the conductive strip transferring process 120.
In the conductive strip transferring process 120, an antenna sheet 30 is affixed on an exterior surface of the glass sheet 12b. The exterior surface of the glass sheet 12b is an exterior surface of the interior glass sheet 12b as stated earlier, that is to say, a surface of the glass sheet 12b confronting the glass sheet 12a when being laminated with the glass sheet 12b (hereinbelow, referred to as “the mating surface 13a”).
As shown in
In the conductive strip transferring process 120, the first detachable layer (mount) 31a is first detached from the antenna sheet 30 (Step 121), and the antenna sheet 30 with the first detachable layer detached therefrom is located at and bonded to a desired position on the mating surface 13a of the glass sheet 12b (Step 122). At that time, the conductive strip 32 is bonded to the mating surface 13a of the glass sheet 12b by the bonding strip 34 as shown in
Next, the second detachable layer (protective film) 31b is detached along with the adhesive layer 35 from the conductive strip 32 as shown in
After that, as required, treatment, such as bending an end portion of the antenna element 20 from an edge portion of the glass sheet 12b (see
When the process 120 for bonding the antenna sheet to the glass sheet 12b is completed as stated earlier, the process proceeds to the glass sheets laminating process 140 to laminate the glass sheet 12b and the glass sheet 12a.
In the glass sheets laminating process 140, the glass sheets, the antenna element and the intermediate film for affixing the antenna element and the glass sheets are formed into a laminated structure, interposing the intermediate film between the glass sheets, and the glass sheets, the antenna element and the intermediate film are press-bonded to obtain a laminated glass. Specifically, the intermediate film 14 is first cut out into substantially the same shape as the glass sheets 12a and 12b, being subjected to a washing step and a film cutting step (Steps 141 and 142), and the intermediate film thus cut out is interposed into between the glass sheet 12a and 12b (Step 143). Thus, the intermediate film 14 is interposed between the mating surface 13a of the glass sheet 12b with the above-mentioned conductive strip 32 bonded thereto and the mating surface of the glass sheet 12a, providing the laminated structure. Next, both glass sheets 12a and 12b are preliminarily press-bonded (Step 144), and both glass sheets are primarily press-bonded together by an autoclave (pressure vessel) (Step 145). As a result, the bonding surfaces between the intermediate film 14 and each of both glass sheets 12a and 12b are completely evacuated and melt-bonded, and thus the laminated glass 10 is completed.
Additionally speaking, the antenna sheet 30 (the conductive strip 32) is bonded to the mating surface 13a of the glass sheet 12b, which is a convex side, in this embodiment. In this embodiment, a tension is placed on the antenna sheet 30 at the time of affixture as opposed to a case where the antenna sheet 30 is affixed to a concave side (for example, the interior surface of the glass sheet 12a). Accordingly, the antenna sheet 30 is unlikely to be wrinkled, providing good workability. Additionally, the weather resistance of the antenna element 20 is improved since the conductive strip 32 is located on a position closer to the interior of the vehicle than the intermediate film 14 having a UV cutting function.
Although the conductive strip transferring process 120 may be manually performed by an operator in this embodiment, this process may be automated, using, e.g., a robot. The antenna sheet 30 does not always need to be delivered, being separated from other antenna sheets. As another delivery mode, plural antenna sheets 30, which are separable from each other, are continuously wound on a roll, and the respective antenna sheets may be separated from each other, being unwound from the roll on the production line.
The glass sheets forming process stated earlier is an example. The glass sheets may be bent by being pressed by a convex mold from above, instead of being bent in a curved shape by gravity while being carried on a frame.
Although explanation has been made about a case where the antenna sheet is affixed to the glass sheets, the present invention is not limited to such a case. The antenna sheet may be affixed to the intermediate film after the intermediate film has been laminated on a glass sheet. Or, the intermediate film may be laminated to the glass sheets, having the antenna sheet pre-affixed thereto.
The antenna sheets 30 shown in
The conductive strip 32 may be made of soft copper. The bonding strip 34 or the adhesive layer 35 may be made of an acrylic adhesive material. The second detachable layer may be made of a polyester film. The first detachable layer 31a may be made of woodfree paper having a single side polylaminated or a resin sheet (such as a PET sheet), which is treated so as to have a detachable property.
In the conventional intermediate film embedded type with an antenna wire embedded in an intermediate film, when adopting a pattern which has intersections 33 where antenna-forming strips intersect in a T-character shape or a cross shape as shown in
On the other hand, in this embodiment, even when adopting a pattern which has intersections 33 where antenna-forming strips intersect in a T-character shape or a cross shape as shown in
The line width W of the conductive strip 32 satisfies the formula of 0.15≦W≦0.4 mm, preferably the formula of 0.2≦W≦0.3 mm, in an antenna pattern portion as a portion excluding edge portions, an electrode portion or the like. This arrangement can provide the laminated glass with a good appearance and is advantageous from the viewpoint that the antenna element is prevented from obstructing a driver's view when the laminated glass is used as an automobile windshield. Explanation of this embodiment has been made about a case wherein the conductive strip 32 is formed by stamping a transfer film material. The bonding strip may be formed on a surface of the conductive strip after forming the pattern by the conductive strip.
It should be noted that after stamping, a portion of the conductive strip other than the patterned portion is removed, that the second detachable layer 31b is combined with the first detachable layer 31a with the stamped conductive strip 32 and bonding strip 34 being interposed therebetween through the adhesive layer 35, and that the combination is passed between rollers to complete the antenna sheet 30.
This embodiment is related to an antenna-embedded laminated glass 10, which is produced by using the antenna sheet 30 shown in
The extension 32b is folded at an edge portion of the glass sheet 12b toward an opposite surface 13b of the glass sheet 12b. This folding step is performed by folding a leading portion of the antenna sheet 30 toward the opposite surface 13b of the glass sheet 12b along a folding line H as shown in
An end of the extension 32b is connected to an electrode 40, which is formed on the opposite surface 13b of the glass sheet 12 by, e.g., printing. The connection between the edge of the extension 32b and the electrode 40 is made by soldering after the above-mentioned primary press-bonding treatment (Step 145) has been completed.
The electrode 40 is connected to an amplifier (not shown) through a wire (not shown), the amplifier being disposed on a vehicle side for amplifying an electromagnetic wave received by the antenna element 20. When the antenna is activated, an electromagnetic wave received by the antenna element 20 is taken out through the electrode 40, is subjected to processing (such as amplification) as required and is supplied to an in-vehicle media system, such as a TV receiver. The electromagnetic wave received by the antenna element 20 may be wirelessly transmitted an in-vehicle media system through a Bluetooth receiver or a wireless LAN receiver connected the electrode 40.
In this embodiment, each of the antenna elements 20 has an electrode per se comprising a portion of the conductive strip 32 formed in a desired shape. In other words, the conductive strips 32 in this embodiment are stamped so that each of the conductive strips comprises a thin linear portion 32a having a constant line width W satisfying the formula of 0.15≦W≦0.4 mm and an electrode 32c having a region formed in a desired shape.
The opposite surface 13b of the glass sheet 12b, which is to be located at the most interior side among the glass sheets forming the laminated glass 10, has an electrode 40 disposed at a position to confront the electrode 32c by, e.g., printing. The electrode 40 may be formed by affixing copper foil having a bonding strip. Thus, the electrode 40 and its corresponding electrode 32c can be connected through static capacitive coupling (electromagnetic coupling). The electrode 40 is connected to an in-vehicle amplifier (not shown) through a wire (not shown), the amplifier serving as amplifying an electromagnetic wave received by the antenna element 20. When the antenna is activated, an electromagnetic wave received by the antenna element 20 is taken out through the static capacitive coupling between the electrode 40 and the electrode 32, is subjected to processing (such as amplification) as required and is supplied to an in-vehicle media system, such as a TV receiver, through an external wire (not shown). An electromagnetic wave received by the antenna element 20 may be wirelessly transmitted to an in-vehicle media system through a Bluetooth receiver or a wireless LAN receiver connected to the electrodes 40.
In this embodiment, it is not necessary to connect each of the electrodes 40 and the antenna element 20 on the laminated glass 10 by soldering, and it is possible to connect an in-vehicle media system and the antenna element 20 through static capacitive coupling. Accordingly, it is possible to avoid inconvenience that a heat stress is generated in the glass sheets 12a and 12b because of heat generated during soldering.
Although preferred embodiments of the present invention have been described in detail, the present invention is not limited to the above-mentioned embodiments. It is to be understood that various modifications or changes are applicable to the above-mentioned embodiments without departing from the sprit and the scope of the present invention.
Although the above-mentioned embodiments have been described in a case wherein the antenna sheet 30 is disposed between the intermediate film 14 and the mating surface 13a of the interior glass sheet 12b, it is to be understood that the present invention does not exclude a structure wherein the antenna sheet 30 is disposed between the intermediate film 14 and the exterior glass sheet 12a.
The intermediate film 14 cannot always comprise a single layer. The intermediate film may comprise plural layers between the two glass sheets 12. The intermediate film 14 may have another function, such as a sound isolation function or heat reflection function.
Number | Date | Country | Kind |
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2004-318022 | Nov 2004 | JP | national |
The present application is a continuation-in-part of U.S. application Ser. No. 12/114,201, filed May 2, 2008, which is a continuation application of U.S. Pat. No. 7,379,028, issued on May 27, 2008. The present application claims a priority under 35 U.S.P. §119 to Japanese Patent Application No. 2004-318022, filed on Nov. 1, 2004. The specifications, the claims, the drawings and the summaries of these applications are incorporated herein by reference in their entirety.
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Number | Date | Country | |
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20100231466 A1 | Sep 2010 | US |
Number | Date | Country | |
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Parent | 11261509 | Oct 2005 | US |
Child | 12114201 | US |
Number | Date | Country | |
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Parent | 12114201 | May 2008 | US |
Child | 12556047 | US |