There has been known a glass antenna, which adds an antenna function of receiving, e.g., AM, FM or TV waves to a window glass for automobiles by forming an antenna conductor in an antenna pattern for reception of electromagnetic waves in the window glass. Such a glass antenna is formed in a fixed window, such as a front windshield comprising laminated glass, or a rear windshield or a side windshield comprising tempered glass.
Laminated glass is prepared by bonding a plurality of glass sheets through an intermediate film. The antenna pattern is formed by, e.g., sealing an antenna conductor and an electrode connected to one end of the antenna conductor between glass sheets. There has been known a technique that an electrode embedded in the glass sheets (hereinbelow, referred to as the “embedded electrode”), and an electrode connected to a lead wire leading to an external electronic instrument and disposed on a surface of laminated glass (hereinbelow, referred to as the “external electrode”) are confronted each other so that an electromagnetic wave, which is received by the antenna pattern, is transmitted to the lead wire through electrostatic-capacitive coupling between both electrodes (see, e.g., Patent Documents 1, 2 and 3).
The wire connection structure using such electrostatic-capacitive coupling does not need to take out the antenna conductor from an end face of the laminated glass in contrast to a wire connection structure wherein a lead wire disposed on the surface of laminated glass is directly connected to the antenna conductor embedded in laminated glass. Further, the wire connection structure using such electrostatic-capacitive coupling does not need to form a notch, which is required to expose an embedded electrode outside the laminated glass. As a result, the wire connection structure using such electrostatic-capacitive coupling needs no special handling for laminated glass and can prevent the formation of a notch from reducing the strength of the laminated glass.
FIG. 8 is a schematic perspective view showing a conventional wire connection structure for laminated glass directed to automobiles, which utilizes electrostatic-capacitive coupling. Laminated glass 51 comprises two glass sheets 56a and 56b bonded together through an intermediate film 57. The two glass sheets 56a and 56b have an antenna conductor 59 and an embedded electrode 58 interposed therebetween, and the glass sheet 56a has an external electrode 87 disposed thereon at such a position to confront the embedded electrode 58. The external electrode 87 is made of a baked silver paste. To the external electrode 87, a terminal 73, which is formed in a shape shown as flat Male Blade for Automobile (Symbol PA, PB) prescribed by JIS-D5403, is soldered. The antenna conductor 59 is connected to a lead wire 4 through electrostatic-capacitive coupling between the embedded electrode 58 and the external electrode 87 by connecting the terminal 73 to a connector 5 connected to the lead wire 4. The connector 5 is provided with a switch. The connector 5 can be disconnected from the terminal 73 by depressing the switch.
Patent document 1: JP-A-2-82701
Patent document 2: JP-A-61-30102
Patent document 2: JP-U-5-43608