Vehicular window glass and method for producing the same

Abstract

To provide vehicular window glass that enables enhancement of terminal joint strength and a method for producing the same.SOLUTION: Vehicular window glass (1) comprises a terminal-equipped glass plate (11X) including: a glass plate (11); a conductor (20) formed on one surface of the glass plate (11), comprising silver and glass frit, and having a terminal joining portion (20T) to which the terminal (102) is joined; and a terminal (102) joined to the terminal joining portion (20T) of the conductor (20) via a lead-free solder (101). The surface of the lead-free solder (101) on the terminal (102) side has a porosity of 15% or less.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to vehicle glazings and methods of making the same. [Background technology]

[0002] For window glass for vehicles such as automobiles, laminated glass in which multiple glass sheets are bonded together or tempered glass is preferably used. Generally, a glass sheet used as the material for the vehicle window glass has a light-shielding layer formed on its peripheral region and is processed into a curved shape by thermoforming. Vehicle window glass is also known that includes an electrical function unit or a conductor connected to the electrical function unit, and a power supply member such as a harness or cable. Examples of the electrical function unit include a heating wire, an electrical heating layer, an antenna, a light-controlling layer, a light-emitting element, and combinations thereof. The conductor may include a power supply unit for supplying power to the electrical function unit. In this specification, a glass plate having an electric conductor is referred to as a "glass plate with an electric conductor."

[0003] For example, in the case of a windshield and / or rear window, an electric heating wire or layer may be formed on the lower and side edges of the window glass to melt frost, snow, ice, etc. that has adhered to the wipers and prevent the wipers from freezing. An optical device including an optical device such as an ADAS (Advanced Driver Assistance Systems) camera, LiDAR (Light Detection and Ranging), radar, or optical sensor that acquires information about the area in front of or behind the vehicle for the purposes of autonomous driving and preventing collision accidents may be installed on the inner surface of the windshield and / or rear window, along with a housing called a bracket or the like that houses the optical device. In such a configuration, to improve the sensing accuracy of the optical device, a conductor may be formed on the glass portion in front of the optical device, including an electrical function unit consisting of one or more heating wires that removes and prevents the adhesion of fogging, frost, snow, ice, etc., and a power supply unit such as a pair of power supply electrodes (bus bars). An antenna for receiving radio waves may be formed on the windshield and / or rear window. The antenna may include one or more antenna wires and one or more power feeding portions such as power feeding electrodes (bus bars).

[0004] In the vehicle window glass described above, power supply members such as harnesses and cables are joined to the power supply electrodes of the power supply unit. Because the power supply unit requires an area for joining the power supply members, it is designed to be thicker than conductive wires such as heating wires and antenna wires. For this reason, the power supply unit is generally formed on a light-shielding layer so that it is not visible to people outside the vehicle. The light-shielding layer can be formed, for example, by coating and firing a ceramic paste containing a black pigment and glass frit. The conductor can be formed, for example, by coating and firing a silver-containing paste containing silver powder and glass frit. The firing of the ceramic paste and the silver-containing paste can be carried out simultaneously with the thermoforming of the glass plate.

[0005] Conventionally, the power supply portion and the power supply member are joined together using solder. For example, a terminal is fixed to the tip of a power supply component such as a wire harness, and this terminal is joined to the power supply component using solder. Solder can be either leaded or lead-free. In recent years, concerns about the environmental impact of lead have led to widespread legal restrictions on leaded solder, making it desirable to use lead-free solder. For example, Patent Document 1 discloses a vehicle window glass having a conductive layer with a terminal connection portion and a connection terminal soldered to the terminal connection portion with lead-free solder (claim 1). Generally, the melting point of lead-free solder is, for example, about 220°C, and soldering must be performed at a higher temperature (for example, about 300°C). In this specification, a glass plate having an electric conductor and a terminal is referred to as a "glass plate with terminals." [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2012 / 096373 Summary of the Invention [Problem to be solved by the invention]

[0007] According to the inventor's research, it has been found that when a glass plate with terminals to which terminals are joined using lead-free solder is placed in an environment such as a high temperature environment, a cold environment, a high humidity environment, a temperature change environment, or a combination of these, the terminal joining strength may decrease.

[0008] The present disclosure has been made in consideration of the above circumstances, and aims to provide a vehicle window glass that includes a portion where a conductor and a terminal are joined using lead-free solder and that is capable of increasing terminal joining strength, and a manufacturing method thereof. [Means for solving the problem]

[0009] The present disclosure provides the following vehicle window glass and a manufacturing method thereof [1] to

[13] .

[0010] [1] A vehicle window glass comprising a glass plate with a terminal, the glass plate having a conductor formed on one surface of the glass plate, the conductor including silver and glass frit, and having a terminal joint portion to which a terminal is joined, and a terminal joined to the terminal joint portion of the conductor via lead-free solder, The vehicle window glass has a porosity of 15% or less on the surface of the lead-free solder on the terminal side (also called the terminal bonding surface).

[0011] [2] The vehicle window glass according to [1], wherein the porosity of the surface (terminal bonding surface) of the lead-free solder on the terminal side is 10% or less. [3] The vehicle window glass according to [1] or [2], wherein the glass plate with terminals has a light-shielding layer between the glass plate and at least a portion of the electrical conductor including the terminal joint portion. [4] The vehicle window glass according to [3], wherein the light-shielding layer contains a black pigment and glass frit.

[0012] [5] The vehicle window glass according to any one of [1] to [4], wherein the glass plate is tempered glass. [6] A laminated glass in which a plurality of glass plates including the glass plate with terminals are bonded together via an interlayer film, and the conductor is formed on the interlayer film side of the glass plate with terminals, The vehicle window glass according to any one of [1] to [4], wherein the glass plate with terminal has an exposed portion that is not covered by the glass plate facing the intermediate film via the intermediate film, and the terminal joint portion of the conductor is formed on the exposed portion.

[0013] [7] A vehicle window glass according to any one of [1] to [4], comprising a laminated glass in which a plurality of glass plates including the glass plate with terminals are bonded together via an interlayer film, and the conductor is formed on the side of the glass plate with terminals opposite to the interlayer film side. [8] The glass plate with terminals has, in a plan view, an optical device mounting area in which an optical device is mounted, a light-transmitting portion located within the optical device mounting area and through which incident light from the outside to the optical device and / or emitted light from the optical device passes, and a light-shielding layer surrounding at least a portion of the light-transmitting portion in a plan view, The vehicle window glass according to [7], wherein the conductor includes a heating wire formed inside the translucent portion, a power supply portion formed outside the translucent portion, and a connection wiring formed outside the translucent portion and connecting the heating wire and the power supply portion. [9] The vehicle window glass according to [8], wherein in the glass plate with terminals, the connection wiring and the power supply part are formed on the light-shielding layer.

[0014]

[10] The conductor includes an electrical function or is electrically connected to an electrical function; the conductor includes a power supply portion for supplying power to the electrical function portion, the power supply portion including the terminal joint portion; The vehicle window glass according to any one of [1] to [9], wherein a power supply member made of a round or foil conductor is fixed to the terminal.

[0015]

[11] A step (X) of preparing a glass plate with a conductor, in which the conductor is formed on the surface of the glass plate; and a step (Y) of joining the terminal to the terminal joining portion of the conductor via lead-free solder, Process (Y) is A step (Y1) of preparing lead-free solder having a flat surface and a convex curved surface opposite to the flat surface; and (Y2) heating and melting the lead-free solder in a state in which the flat surface of the lead-free solder is in contact with the terminal and the convex curved surface of the lead-free solder is in contact with the surface of the terminal joint portion of the conductor.

[0016]

[12] Step (X) a step (X2) of applying a silver-containing paste containing silver and glass frit as the conductive material onto the surface of the glass plate to form a silver-containing paste layer; and (X3) firing the silver-containing paste layer to form the conductor.

[0017]

[13] Step (X) a step (X1) of applying a ceramic paste containing a black pigment and glass frit, which are materials for a light-shielding layer, onto the surface of the glass plate to form a ceramic paste layer; a step (X2) of applying a silver-containing paste containing silver and glass frit as the conductive material onto the surface of the glass plate to form a silver-containing paste layer; and (X3) firing the ceramic paste layer and the silver-containing paste layer to form the light-shielding layer and the conductor. [Effects of the Invention]

[0018] In the vehicle window glass of the present disclosure, the surface on the terminal side of the lead-free solder (terminal bonding surface) has a porosity of 15% or less. According to the present disclosure, it is possible to provide a vehicle window glass that includes a portion where a conductor and a terminal are bonded using lead-free solder and that can increase the terminal bonding strength, and a manufacturing method thereof. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an overall plan view of a vehicle window glass according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a partially enlarged plan view of FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4A] 1A to 1C are process diagrams illustrating a method for manufacturing a vehicle window glass according to a first embodiment. [Figure 4B] 1A to 1C are process diagrams illustrating a method for manufacturing a vehicle window glass according to a first embodiment. [Figure 4C] 1A to 1C are process diagrams illustrating a method for manufacturing a vehicle window glass according to a first embodiment. [Figure 4D] 1A to 1C are process diagrams illustrating a method for manufacturing a vehicle window glass according to a first embodiment. [Figure 4E] 1A to 1C are process diagrams illustrating a method for manufacturing a vehicle window glass according to a first embodiment. [Figure 4F] 1A to 1C are process diagrams illustrating a method for manufacturing a vehicle window glass according to a first embodiment. [Figure 5A] 1A to 1C are process diagrams of a solder bonding method using a lead-free solder chip according to a first embodiment. [Figure 5B] 1A to 1C are process diagrams of a solder bonding method using a lead-free solder chip according to a first embodiment. [Figure 5C] 1A to 1C are process diagrams of a solder bonding method using a lead-free solder chip according to a first embodiment. [Figure 5D] 1A to 1C are process diagrams of a solder bonding method using a lead-free solder chip according to a first embodiment. [Figure 6A] 10A to 10C are process diagrams of a solder bonding method using a lead-free solder chip according to a second embodiment. [Figure 6B] 10A to 10C are process diagrams of a solder bonding method using a lead-free solder chip according to a second embodiment. [Figure 6C] 10A to 10C are process diagrams of a solder bonding method using a lead-free solder chip according to a second embodiment. [Figure 6D] 10A to 10C are process diagrams of a solder bonding method using a lead-free solder chip according to a second embodiment. [Figure 7] FIG. 4 is a cross-sectional view showing a design modification example of the first embodiment. [Figure 8A] FIG. 4 is an overall plan view of a vehicle window glass according to a second embodiment of the present invention. [Figure 8B] FIG. 8B is a partially enlarged plan view of FIG. 8A. [Figure 9A] FIG. 8C is a cross-sectional view taken along line IXA-IXA of FIG. 8B. [Figure 9B] FIG. 8B is a cross-sectional view taken along line IXB-IXB of FIG. 8B. [Figure 9C] 8C is a cross-sectional view taken along line IXC-IXC of FIG. 8B. [Figure 10] FIG. 10 is a partial plan view of a vehicle window glass according to a third embodiment of the present invention. [Figure 11] 1 shows examples of surface images of the lead-free solder terminal side of the glass plates with terminals obtained in Examples 1 to 3 and 11. [Figure 12A] 1 is a graph showing the evaluation results of the glass plates with terminals obtained in Examples 1 to 3 and 11. [Figure 12B] 1 is a graph showing the evaluation results of the glass plates with terminals obtained in Examples 1 to 3 and 11. [Figure 12C] 1 is a graph showing the evaluation results of the glass plates with terminals obtained in Examples 1 to 3 and 11. DETAILED DESCRIPTION OF THE INVENTION

[0020] Generally, thin film structures are referred to as "films" or "sheets" depending on their thickness. In this specification, no clear distinction is made between these terms. Therefore, in this specification, "films" may include "sheets." In this specification, the term "approximately" attached to a shape means a partially changed shape, such as a chamfered shape with rounded corners, a shape with a part missing, or a shape with an arbitrary small shape added to the shape. In this specification, unless otherwise specified, the term "surface of a glass plate" refers to the main surface having the largest area, excluding the end faces (also called side faces) of the glass plate. In this specification, unless otherwise specified, the terms "up and down," "left and right," "vertical and horizontal," and "inside and outside" refer to the state in which the vehicle window glass is fitted into the vehicle (actual state of use). In this specification, "lead-free solder" refers to solder that is substantially free of lead, and the lead content in lead-free solder is 500 ppm or less. In this specification, unless otherwise specified, when lead-free solder is "substantially free of a metal element other than lead," it means that the content of that metal element is 1000 ppm or less. In this specification, unless otherwise specified, the use of "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. Hereinafter, an embodiment of the present invention will be described.

[0021] [Vehicle window glass and its manufacturing method] The present disclosure relates to a vehicle window glass including a glass plate with a terminal and a method for manufacturing the same. Examples of vehicle window glass include windshields, side windows, and rear windows. The vehicle window glass of the present disclosure may include laminated glass, tempered glass, or organic glass, and preferably includes laminated glass or tempered glass. The laminated glass may have a structure in which a plurality of glass plates, including a terminal-equipped glass plate, are bonded together via an interlayer film. When the vehicle window glass includes laminated glass, the conductor may be formed on the interlayer film side of the terminal-equipped glass plate, or on the side of the terminal-equipped glass plate opposite to the interlayer film side.

[0022] The type of glass plate that is the material for laminated glass and tempered glass is not particularly limited, and examples include soda lime glass, borosilicate glass, aluminosilicate glass, lithium silicate glass, quartz glass, sapphire glass, and alkali-free glass.

[0023] There are no particular restrictions on the thickness of the laminated glass, and for use as a window glass for a vehicle, the thickness is preferably 2 to 6 mm. When the laminated glass is composed of two glass sheets, the thickness of the glass sheet on the interior side of the vehicle and the thickness of the glass sheet on the exterior side of the vehicle may be the same or different. The thickness of the glass sheet on the interior side of the vehicle is preferably 0.3 to 2.3 mm. If the thickness of the glass sheet on the interior side of the vehicle is 0.3 mm or more, handling is easy, and if it is 2.3 mm or less, the mass is not too large. The thickness of the glass sheet on the exterior side of the vehicle is preferably 1.0 to 3.0 mm. If the thickness of the glass sheet on the exterior side of the vehicle is 1.0 mm or more, sufficient strength for stone chip resistance and the like is achieved, and if it is 3.0 mm or less, the mass of the laminated glass is not too large, which is preferable in terms of vehicle fuel efficiency. If the thickness of the glass sheet on the exterior side of the vehicle and the thickness of the glass sheet on the interior side of the vehicle are both 1.8 mm or less, the laminated glass can be made both lightweight and soundproof, and this is preferable.

[0024] The thickness of the tempered glass is not particularly limited, and is preferably 1.5 to 6 mm for use as vehicle window glass (windshield, side glass, rear glass, etc.). If the thickness of the tempered glass is 1.5 mm or more, it is easy to obtain tempered glass in which the surface compressive stress and the corresponding internal tensile stress satisfy the fracture standard in the air-cooling tempering method.

[0025] The multiple glass sheets constituting the laminated glass are usually a combination of multiple untempered glasses, but may also be a combination of tempered glass and untempered glass. In the laminated glass, when the thickness of the glass sheet on the vehicle interior side is 1.0 mm or less, this glass sheet may be chemically tempered glass. When the glass sheet on the vehicle interior side is chemically tempered glass, it is preferable that the compressive stress value of the glass surface is 300 MPa or more and the depth of the compressive stress layer is 2 μm or more.

[0026] The vehicle window glass may have a curved shape such that the vehicle exterior side is convex when installed in a vehicle. When the vehicle window glass is laminated glass, both the glass sheet on the vehicle interior side and the glass sheet on the vehicle exterior side may have a curved shape such that the vehicle exterior side is convex. The vehicle window glass may have a single curved shape, curved in only one of the left-right direction or the up-down direction, or a compound curved shape, curved in both the left-right direction and the up-down direction. The radius of curvature of the vehicle window glass may be 2000 to 11000 mm. The radius of curvature of the vehicle window glass in the left-right direction and the up-down direction may be the same or different. Gravity forming, press forming, roller forming, etc. are used to bend the vehicle window glass.

[0027] The laminated glass and tempered glass may have a functional film on at least a portion of the surface, which has functions such as water repellency, low reflectivity, low radiation, ultraviolet shielding, infrared shielding, and coloring. The laminated glass may have, in at least a partial region of its interior, a functional film having functions such as low reflectivity, low emissivity, ultraviolet shielding, infrared shielding, coloring, etc. At least a partial region of the interlayer film of the laminated glass may have functions such as ultraviolet shielding, infrared shielding, coloring, etc. The interlayer film of the laminated glass may be a single layer film or a laminated film.

[0028] The vehicle window glass of the present disclosure includes a glass plate; a terminal-equipped glass plate having a conductor formed on one surface of the glass plate and made of a material containing silver and glass frit, the conductor having a terminal joint portion to which a terminal is joined, and a terminal joined onto the terminal joint portion of the conductor via lead-free solder. In this specification, the "terminal joint" of a conductor refers to the portion of the conductor directly below the lead-free solder.

[0029] The conductor may be formed directly on the surface of the glass plate in contact with the glass plate, or may be formed on any component formed on the surface of the glass plate. The glass plate with terminals may have a light-shielding layer applied between the glass plate and the terminal joint of the conductor. In this case, the conductor may be formed on the light-shielding layer formed on the glass plate. The conductor is formed by applying a silver-containing paste containing silver powder and glass frit onto a glass plate and firing it. The thickness of the conductor is not particularly limited and is, for example, 5 to 20 μm, preferably 5 to 10 μm.

[0030] The silver-containing paste contains silver powder and glass frit, and may further contain a vehicle and one or more additives as needed.

[0031] The silver powder is composed of particles containing silver and / or a silver alloy. The content of the silver powder in the silver-containing paste is preferably 65 to 85 mass%, more preferably 75 to 85 mass%, and particularly preferably 80 to 85 mass%. If the content of the silver powder is within this range, it is easy to adjust the resistivity of the conductor within a suitable range. The average particle size of the silver powder is preferably 0.1 to 10 μm. The upper limit is more preferably 7 μm. If the average particle size of the silver powder is within the above range, it is easy to adjust the resistivity of the conductor within a suitable range. In this specification, unless otherwise specified, the "average particle size of silver powder" refers to the average particle size (D50) measured by a laser scattering particle size distribution analyzer.

[0032] Examples of glass frits include Bi2O3-B2O3-SiO2-based glass frits and B2O3-SiO2-based glass frits. The content of the glass frit in the silver-containing paste is preferably 2 to 10 mass%, more preferably 3 to 8 mass%. If the content of the glass frit is 2 mass% or more, the conductor is easily sintered, and if it is 10 mass% or less, the resistivity of the conductor is easily adjusted within a suitable range.

[0033] Examples of the vehicle include a resin solution in which a binder resin such as ethyl cellulose resin, acrylic resin, or alkyd resin is dissolved in a solvent such as α-terpineol, butyl carbitol acetate, or ethyl carbitol acetate. The content of the vehicle in the silver-containing paste is preferably 10 to 45% by mass, more preferably 15 to 25% by mass.

[0034] Examples of additives include resistance adjusters such as Ni, Al, Sn, Pt, and Pd; and colorants such as V, Mn, Fe, Co, Mo, and compounds thereof. The content of the additives in the silver-containing paste (the total amount when multiple types are used) is preferably 2% by mass or less. The upper limit is more preferably 1% by mass.

[0035] The electrical conductors may include or be electrically connected to electrical functions. The electrical functional part may include one or more heating wires, heating layers, antennas, dimming layers, light-emitting elements, and combinations thereof. Light-emitting elements may include LEDs (Light Emitting Diodes) and OLEDs (Organic Light Emitting Diodes). The one or more heating wires or layers can remove and prevent the adhesion of frost, snow, ice, etc. The one or more heating wires or layers can be used, for example, to prevent windshield wipers from freezing, or to improve the sensing accuracy of optical devices, including optical instruments such as cameras and radars. The antenna includes one or more antenna wires, and may include multiple types of antenna wires with different patterns and / or lengths depending on the wavelength of the radio waves to be received. The electrical functional portion can be manufactured by a known method.

[0036] The conductor may include a power supply portion for supplying power to the electrical function portion, and the power supply portion may include a terminal junction. The power supply portion may include one or more power supply electrodes (also called bus bars), and each power supply electrode may include a terminal junction. When the power supply unit includes a pair of power supply electrodes, one of the power supply electrodes is a positive electrode and is connected to a power source or a signal source provided in the vehicle via a power supply member, and the other power supply electrode is a negative electrode and is connected to the vehicle body (earth) via the power supply member. Note that there may be one or more power supply electrodes for the positive electrode, and there may be one or more power supply electrodes for the negative electrode. When the conductor is connected to the electrical function part, the conductor and the electrical function part may be formed on the same glass surface or on different glass surfaces.

[0037] A power supply member made of a round or foil conductor can be fixed to the terminal. In this specification, the term "conductor" includes a coated conductor, which is one or more conductors coated with an insulating material. A coated conductor is preferred as the power supply member. Specific examples of the power supply member include harnesses and cables. Examples of round conductors include wire harnesses. Examples of foil conductors include flat harnesses and flexible printed circuit boards. The power supply member has an exposed conductor portion, and the terminal is fixed to this exposed conductor portion. The material of the exposed conductor portion is not particularly limited, and examples thereof include Cu, Al, Ag, Au, Ti, Sn, Zn, alloys thereof, and combinations thereof. The exposed conductor portion may be a main metal whose surface is plated with another metal. The exposed conductor portion may have a thin oxide film on its surface.

[0038] Generally, when a glass sheet with a conductor is soldered, it is locally heated to a high temperature and then cooled to room temperature, which can cause residual stress after the temperature is lowered. This residual stress can cause cracks in the glass sheet with a conductor after the window glass is manufactured. Generally, the melting point of lead-free solder is higher than that of lead-containing solder, so when lead-free solder is used, greater stress is generated in the glass plate with conductor. Furthermore, since lead-free solder does not contain lead, which has a low elastic modulus, it has a higher elastic modulus than lead-containing solder and is less likely to deform, so the generated stress is less likely to be relieved. For these reasons, problems such as residual stress after joining and the resulting cracking after manufacturing can occur, especially when lead-free solder is used.

[0039] Lead-free solder is solder that contains little or no lead, and known types can be used. Examples of lead-free solder include SnAg-based solders containing Sn and Ag, SnAgCu (SAC)-based solders containing Sn, Ag, and Cu, SnZnBi-based solders containing Sn, Zn, and Bi, SnCu-based solders containing Sn and Cu, SnZnAl-based solders containing Sn, Zn, and Al, and In-based solders containing In.

[0040] From the viewpoint of environmental resistance, etc., preferred lead-free solders include, for example, SnAg-based lead-free solders that contain Sn and Ag but are substantially free of Sb, Cu, and In; and SnAgCu (SAC)-based lead-free solders that contain Sn, Ag, and Cu but are substantially free of Sb and In. The melting point of lead-free solder such as SnAg-based and SnAgCu-based solder is higher than that of leaded solder, for example, about 220° C. When lead-free solder such as SnAg-based and SnAgCu-based solder is used, the soldering temperature is, for example, about 300° C.

[0041] Preferred embodiments of SnAg-based and SnAgCu-based lead-free solders will be described below. The Sn content in SnAg-based and SnAgCu-based lead-free solders is not particularly limited, but is preferably 95% by mass or more, more preferably 95 to 98.5% by mass, and particularly preferably 96 to 98% by mass. If the Sn content is 95% by mass or more (the Ag content is 5% by mass or less), the melting point of the lead-free solder can be relatively low, which allows the soldering temperature to be relatively low and the temperature rise of the glass plate to be relatively small. As a result, residual stress generated in the glass plate and the resulting cracking of the glass plate can be suppressed.

[0042] Generally, when using Sn-based lead-free solder that does not contain Ag, the Sn in the lead-free solder is highly compatible with the Ag in the conductor, which means that the Ag in the terminal joint of the conductor easily penetrates into the Sn-containing lead-free solder, a phenomenon known as "silver erosion." In this case, the terminal joint may discolor due to deterioration and thinning, resulting in poor appearance. When lead-free solder containing Sn and Ag is used, the Sn in the lead-free solder has already formed a compound with Ag, which prevents Ag in the terminal joint of the conductor from penetrating into the lead-free solder, thereby preventing discoloration of the terminal joint and the resulting poor appearance. The Ag content in the lead-free solder is preferably 1.5 to 5 mass%, more preferably 2 to 4 mass%. If the Ag content is 1.5 mass% or more, the penetration of Ag in the terminal joint of the conductor into the lead-free solder can be effectively suppressed, and good joint strength can be obtained. If the Ag content is 5 mass% or less, the material cost of the lead-free solder can be kept low, and the melting point of the lead-free solder can be kept relatively low.

[0043] The lead-free solder may contain Cu as a metal element other than Sn and Ag. The Cu content in the lead-free solder is not particularly limited, but is preferably 1 mass % or less, and more preferably 0.5 mass % or less. An example of the composition of SnAg-based lead-free solder is 98% by mass of Sn and 2% by mass of Ag. An example of the composition of SnAgCu-based lead-free solder is 96.5% by mass of Sn, 3.0% by mass of Ag, and 0.5% by mass of Cu.

[0044] From the viewpoint of reducing thermal stress on the glass plate when terminals are attached, indium-based lead-free solder containing indium, which is a low-melting point solder, is also preferred. In-based lead-free solder: SnIn-based lead-free solder containing Sn and In and substantially free of Sb, Ag, and Cu; SnAgIn-based lead-free solder containing Sn, Ag, and In, and substantially free of Sb, Cu, Bi, Ni, and Zn; SnAgInCu-based lead-free solder containing Sn, Ag, In, and Cu, and substantially free of Sb, Bi, Ni, and Zn; SnAgInBi-based lead-free solder containing Sn, Ag, In, and Bi, and substantially free of Sb, Cu, Ni, and Zn; Examples include SnAgInNiCuZn-based lead-free solders that contain Sn, Ag, In, Ni, Cu, and Zn and are substantially free of Sb and Bi.

[0045] The glass plate with terminals may have a light-shielding layer between the glass plate and at least a portion thereof, including the terminal joint portion of the conductor. The light-shielding layer may be formed by a known method, for example, by applying a ceramic paste containing a black pigment and glass frit to a predetermined region on the surface of a glass plate or tempered glass, which is a material for the laminated glass, and then firing the paste. The thickness of the light-shielding layer is not particularly limited, and is, for example, 5 to 20 μm. The light-shielding layer may be formed in the peripheral region of any surface of the glass plate or tempered glass, which is a material for the laminated glass.

[0046] As explained in the section [Problem to be Solved by the Invention], a glass sheet with terminals joined with lead-free solder may experience a decrease in terminal joining strength when placed in an environment such as a high-temperature environment, a low-temperature environment, a high-humidity environment, a temperature-varying environment, or a combination thereof. This tendency is particularly evident in a glass sheet with terminals joined with lead-free solder to a power supply part formed on a light-shielding layer. In a conductor containing silver and glass frit, the glass frit component tends to be present in a relatively large amount on the surface of the conductor. In particular, when the conductor is formed on a light-shielding layer, the glass frit component tends to be present in a larger amount on the surface of the conductor. This is presumably because, during firing of the conductor-forming material and the optional light-shielding layer-forming material, a portion of the glass frit component contained in these materials migrates to the surface side. Generally, lead-free solder has low wettability to glass frit components. If a large amount of glass frit components is present on the surface of a conductor, the bond strength of the lead-free solder to the conductor decreases, making it difficult to form a good-shaped solder fillet, which is thought to result in a decrease in terminal bond strength.

[0047] Known glass frits can be used for the conductor and the light-shielding layer. Metal elements that can be used include Na, Al, Si, P, Zn, Ba, and Bi. Generally, glass frits for the conductor and the light-shielding layer contain a relatively large amount of Bi, so the Bi / Ag mass ratio can be used as an indicator of the proportion of the glass frit components on the surface of the conductor. A higher Bi / Ag mass ratio indicates a higher proportion of the glass frit components. The Bi / Ag mass ratio can be measured by energy dispersive X-ray (EDX) analysis or the like.

[0048] In addition, when a conductor is formed on a light-shielding layer, as described above, some of the components of the glass frit contained in the material for forming the light-shielding layer may migrate into the conductor during the manufacturing process, and therefore, some of the components of the glass frit contained in the material for forming the light-shielding layer may be included in the components of the glass frit contained in the conductor.

[0049] According to the inventor's research, it has been found that when the type and amount of lead-free solder and the heating conditions in the solder joining process are the same, the lower the porosity of the terminal side surface (terminal joining surface) of the lead-free solder, the higher the terminal joining strength tends to be after durability tests such as high temperature and high humidity tests and thermal cycle tests. On the terminal side surface (terminal joint surface) of lead-free solder, the lower the porosity, the greater the ratio of the contact area between the lead-free solder and the terminal (effective joint area excluding the void area) to the area of ​​the region surrounded by the outer periphery of the lead-free solder, and it is thought that this will increase the joint strength between the lead-free solder and the terminal. It is also believed that the fewer voids that can become sources of stress on the terminal side surface (terminal bonding surface) of the lead-free solder, the higher the bonding strength between the lead-free solder and the terminal. In the vehicle window glass of the present disclosure, the porosity of the surface on the terminal side of the lead-free solder (terminal bonding surface) is 15% or less. The upper limit is preferably 12%, more preferably 10%, particularly preferably 8%, and most preferably 5%. The lower limit is not particularly limited, and is, for example, 0.1%. By ensuring that the porosity of the terminal side surface (terminal bonding surface) of the lead-free solder is equal to or less than the above upper limit, the terminal bonding strength after durability tests such as high temperature and high humidity tests and thermal cycle tests can be effectively increased.

[0050] In this specification, unless otherwise specified, "porosity" is defined as the ratio of the total area of ​​one or more voids that may exist inside the lead-free solder to the total area of ​​the lead-free solder and one or more voids that may exist inside the lead-free solder (the area of ​​the region surrounded by the outer periphery of the lead-free solder) in a microscope image of the terminal side surface (terminal joint surface) of the lead-free solder, and can be measured by the method described in the "Examples" section below.

[0051] The terminal bond strength at the initial stage, after the high temperature and humidity test, and after the thermal cycle test can be measured by the method described in the section [Examples] below. In this specification, "initial" is defined as the period from when the terminals are joined using lead-free solder, the temperature of the lead-free solder is lowered to room temperature (20 to 30°C), and the glass plate with terminals is left standing at room temperature (20 to 30°C) without any special treatment or operation, until 24 hours have passed.

[0052] The initial terminal bonding strength is not particularly limited, but is preferably 200 N or more. The lower limit is more preferably 230 N, particularly preferably 250 N, and most preferably 280 N. The upper limit is not particularly limited, but is, for example, 400 N or 350 N. The terminal bonding strength after a high-temperature, high-humidity test in which the terminal is stored for 500 hours in an environment of 80°C and 95% relative humidity is not particularly limited, but is preferably 180 N or more. The lower limit is more preferably 190 N, and particularly preferably 200 N. The upper limit is not particularly limited, but is, for example, 350 N or 300 N. The terminal bond strength after a thermal cycle test is not particularly limited, but is preferably 200 N or greater. The lower limit is more preferably 230 N, and particularly preferably 250 N. The upper limit is not particularly limited, but is, for example, 350 N or 300 N.

[0053] The method for producing the vehicle window glass of the present disclosure is not particularly limited. The method for manufacturing a vehicle window glass according to the present disclosure includes, for example, A step (X) of preparing a glass plate with a conductor formed on the surface of the glass plate; The method may include a step (Y) of joining a terminal onto the terminal joining portion of the conductor via lead-free solder.

[0054] In one embodiment, step (X) comprises: a step (X2) of applying a silver-containing paste containing silver as a conductive material and glass frit onto the surface of the glass plate to form a silver-containing paste layer; The method may sequentially include a step (X3) of firing the silver-containing paste layer to form a conductor.

[0055] In another embodiment, step (X) comprises: A step (X1) of applying a ceramic paste containing a black pigment and glass frit, which are materials for a light-shielding layer, onto the surface of a glass plate to form a ceramic paste layer; a step (X2) of applying a silver-containing paste containing silver as a conductive material and glass frit onto the surface of the glass plate to form a silver-containing paste layer; The method may sequentially include a step (X3) of firing the ceramic paste layer and the silver-containing paste layer to form a light-shielding layer and a conductor.

[0056] In the laminated glass, the glass sheet with terminals has an exposed portion that is not covered by the opposing glass sheet with an interlayer film interposed therebetween, the conductor is formed on the interlayer film side of the glass sheet with terminals, and the terminal joint portion of the conductor can be formed on the exposed portion of the glass sheet with terminals. In this embodiment, a step of laminating a plurality of glass plates, including a glass plate with a conductor, via an interlayer film may be included between the step (X) and the step (Y).

[0057] In the laminated glass, the conductor can be formed on the side of the terminal-equipped glass sheet opposite to the interlayer film side. In this embodiment as well, a step of laminating a plurality of glass plates, including a glass plate with a conductor, via an interlayer film may be included between the step (X) and the step (Y).

[0058] Process (Y) is A step (Y1) of preparing lead-free solder having a flat surface and a convex curved surface opposite to the flat surface; The method may include a step (Y2) of heating and melting the lead-free solder while the flat surface of the lead-free solder is in contact with the terminal and the convex curved surface of the lead-free solder is in contact with the surface of the terminal joint portion of the conductor.

[0059] Conventionally, solder chips used for solder bonding have generally been block-shaped or plate-shaped solder chips having a first plane that makes surface contact with a terminal and a second plane that makes surface contact with a conductor (see, for example, Claim 1 of JP 2016-64444 A, Figures 4 and 5 of JP 2020-77468 A, etc.). When using a plate-shaped or block-shaped lead-free solder chip that has a first flat surface that makes surface contact with the terminal and a second flat surface that makes surface contact with the conductor, the lead-free solder chip and the conductor come into surface contact when heating of the lead-free solder chip begins, making it difficult for the flux to escape during the soldering process, and it is thought that voids are likely to remain in the lead-free solder.

[0060] When using a dome-shaped lead-free solder tip with a flat surface and a convex curved surface facing the flat surface, the contact area between the conductor and the lead-free solder tip is small from the time the lead-free solder tip begins to heat until it melts. This makes it easier for the flux to escape during the soldering process, and it is thought that voids are less likely to remain in the lead-free solder. This method makes it less likely for voids to remain in the lead-free solder, effectively reducing the porosity of the lead-free solder's terminal-side surface (terminal joint surface). As a result, the terminal joint strength can be increased after durability tests such as high-temperature, high-humidity tests and thermal cycle tests.

[0061] [First embodiment] The structure of a vehicle window glass according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall plan view of a vehicle window glass of this embodiment. FIG. 2 is a partially enlarged plan view of FIG. 1. FIGS. 1 and 2 are views before terminal joining. Both FIGS. 1 and 2 are perspective views, with the front side of the illustration representing the interior side of the vehicle and the back side of the illustration representing the exterior side of the vehicle. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2. In FIG. 3, the upper side of the illustration represents the exterior side of the vehicle and the lower side of the illustration represents the interior side of the vehicle. These figures are all schematic views, and for ease of viewing, the scale of each component in each figure has been appropriately changed from the actual scale.

[0062] The planar shape of the vehicle window glass 1 can be designed as appropriate, and examples thereof include a shape in which a plate having a generally trapezoidal shape in plan view is curved as a whole, as shown in FIG. As shown in FIG. 3, the vehicle window glass 1 of this embodiment is a windshield or rear glass including a laminated glass 10 in which an outer glass sheet 11 (a glass sheet on the outside of the vehicle) and an inner glass sheet 13 (a glass sheet on the inside of the vehicle) are bonded together via an interlayer film 12. In this embodiment, the laminated glass 10 includes an outer glass sheet 11, a terminal-equipped glass sheet 11X formed on the vehicle interior surface S2 (the surface on the interlayer film 12 side) of the outer glass sheet 11 and made of a material containing silver and glass frit, the conductor 20 having a terminal joint 20T to which a terminal 102 is joined, and the terminal 102 joined via lead-free solder 101 onto the terminal joint 20T of the conductor 20. The laminated glass may be made by bonding three or more glass sheets together.

[0063] 1, the vehicle window glass 1 of this embodiment has one or more light-shielding layers BL in its peripheral region. The number of light-shielding layers BL, the glass surface on which the light-shielding layers BL are formed, and the region in which the light-shielding layers BL are formed can be designed as appropriate. 3, in this embodiment, a light-shielding layer BL2 is formed in the peripheral region of the vehicle interior surface S2 of the outer glass sheet 11, and a conductor 20 including an electrical function portion is formed on this light-shielding layer BL2. Note that in the present disclosure, the terminal-equipped glass sheet 11X can have the light-shielding layer BL2 between the outer glass sheet 11 and the terminal joint portion 20T, in order to obtain an effect of improving the terminal joint strength of the terminal-equipped glass sheet 11X. 3, a light-shielding layer BL4 may be formed in a peripheral region of at least one surface of the inner glass plate 13. In the illustrated example, the light-shielding layer BL4 is formed in a peripheral region of the vehicle interior surface S4 of the inner glass plate 13.

[0064] In this embodiment, the conductor 20 has a function of melting frost, snow, ice, etc. adhering to the wiper, thereby preventing the wiper from freezing. In Fig. 1, the area indicated by the dashed line and marked with the symbol WP is the movable area of ​​the wiper. As shown in FIGS. 1 and 2, the conductor 20 includes an electrical functional portion made up of one or more heating wires 20L or heating layers. Here, the conductor 20 includes a plurality of heating wires 20L as an example. The conductor 20 may further include a power supply portion including a pair of power supply electrodes (a pair of bus bars) 20B. One of the pair of power supply electrodes (a pair of bus bars) 20B is a positive electrode and the other is a negative electrode. The conductor 20 may be formed, for example, at the lower end and / or at least one side end of the vehicle window glass 1. The configuration, pattern, and formation area of ​​the conductor 20 may be designed as appropriate.

[0065] 2 and 3, the inner glass plate 13 has a notch 13N at its lower end, which causes the terminal-equipped glass plate 11X to have an exposed portion 11E that is not covered by the inner glass plate 13 that faces it via the interlayer film 12. In this embodiment, the conductor 20 is formed on the terminal-equipped glass plate 11X on the interlayer film 12 side. At least a portion of each of the pair of power supply electrodes (pair of bus bars) 20B is formed in the exposed portion 11E of the terminal-equipped glass plate 11X and is exposed and not covered by the inner glass plate 13.

[0066] As shown in Fig. 2, in each of the pair of power supply electrodes (pair of bus bars) 20B, the exposed portion 20E of the power supply electrode 20B includes a terminal joint portion 20T, and a terminal 102 is joined to the terminal joint portion 20T via lead-free solder 101. A power supply member 103 made of a round or foil-shaped conductive wire is fixed to the terminal 102. See also Fig. 4D for the exposed portion 20E. The terminal joint 20T of the conductor 20 is the portion directly below the lead-free solder 101. In the drawing, the formation region of the terminal joint 20T is the region sandwiched between two dashed lines T1 and T2. Note that the position of the terminal joint 20T of the conductor 20 is not clearly determined from the beginning. In the power supply electrode 20B, the portion directly below the lead-free solder 101 after the terminal 102 is joined via the lead-free solder 101 is the terminal joint 20T.

[0067] Fig. 5D is a partially enlarged cross-sectional view of the cross section of the laminated structure of terminal 102 / lead-free solder 101 / power supply electrode 20B / light-shielding layer BL2 / outer glass plate 11 shown in Fig. 3, viewed from the left side of Fig. 3. Here, the laminated structure is upside down for easier viewing. The power supply member 103 is preferably a round or foil conductor, more preferably a round or foil coated conductor, and is preferably a wire harness or a flat harness. The tip of the power supply member 103 is an exposed conductor portion, and the terminal 102 is fixed to this exposed conductor portion. A known crimp terminal is preferred as terminal 102. The crimp terminal preferably has power supply member joint 102A (see FIG. 3) that contacts the tip end (exposed conductor portion) of power supply member 103, and solder joint 102B (see FIGS. 3 and 5D) that contacts lead-free solder 101.

[0068] When a wire harness is used as the power supply member 103, a preferred crimp terminal is one that includes a power supply member joint 102A that crimps and fixes the tip end (exposed conductor portion) of the wire harness, and a bridge-like portion with solder joints 102B at both ends, as shown in Figures 3 and 5D. The crimp terminal may have one solder joint 102B without a bridge-like portion.

[0069] The terminal 102 is preferably a metal terminal. The metal constituting the terminal is not particularly limited, and examples thereof include metals such as Cu, Fe, Cr, Ni, and Zn; alloys containing one or more metal elements such as Cu, Fe, Cr, Ni, and Zn; and combinations thereof. Examples of alloys include stainless steel (SUS) and brass. The surface of the terminal 102 may be subjected to a surface treatment such as tin plating. At least a portion of the terminal 102 may be covered with an insulating material. The thickness of the terminal 102 is not particularly limited, and is preferably 0.4 to 0.8 mm. The terminal 102 made of a single material can be manufactured, for example, by punching a metal plate (pressing using a punching die) to obtain a metal plate of the desired size and then bending the metal plate. For example, a terminal 102 (preferably a crimp terminal) is fixed by crimping to the tip end (exposed conductor portion) of the power supply member 103, and the terminal 102 is joined to a terminal joint portion 20T in the power supply electrode 20B via lead-free solder 101. The tip end (exposed conductor portion) of the power supply member 103 and the terminal 102 may be connected by soldering or by welding.

[0070] In this embodiment, the porosity of the terminal-side surface (terminal bonding surface) 101S of the lead-free solder 101 (see FIG. 5D) is 15% or less. The upper limit is preferably 12%, more preferably 10%, particularly preferably 8%, and most preferably 5%. The lower limit is not particularly limited, and is, for example, 0.1%. By setting the porosity of the terminal side surface (terminal bonding surface) 101S of the lead-free solder 101 to the above upper limit or less, the terminal bonding strength after durability tests such as high temperature and high humidity tests and thermal cycle tests can be effectively increased.

[0071] (Manufacturing method) An example of the method for manufacturing a vehicle window glass of this embodiment will be described with reference to the drawings, in which: Figures 4A to 4F are schematic cross-sectional views corresponding to Figure 3; The method for manufacturing the vehicle window glass 1 of this embodiment is as follows: a step (X) of preparing a conductor-equipped glass sheet 11Y in which a conductor 20 is formed on the vehicle interior surface S2 of the outer glass sheet 11; and a step (Y) of joining a terminal 102 onto the terminal joining portion 20T of the conductor 20 via lead-free solder 101.

[0072] (Process (X)) The step (X) can include the following steps (X1) to (X3). <Process (X1)> First, as shown in FIG. 4A, a ceramic paste containing a black pigment and glass frit, which are materials for the light-shielding layer BL2, is applied to a predetermined area on the vehicle interior surface S2 of the outer glass sheet 11 as needed, and dried to form a ceramic paste layer BLP. In addition, if necessary, a ceramic paste containing black pigment and glass frit, which are materials for the light-shielding layer BL4, is applied to a predetermined area on the vehicle interior surface S4 of the inner glass plate 13 and dried to form a ceramic paste layer BLP (not shown). The drying conditions for the ceramic paste can be appropriately designed depending on the paste composition, and for example, a temperature of 120 to 150° C. for about 5 minutes is preferred.

[0073] <Process (X2)> 4A, a silver-containing paste containing silver and glass frit, which are materials for the conductor 20, is applied to the vehicle interior surface S2 of the exterior glass sheet 11 and dried to form a conductive paste layer 20P. The drying conditions for the silver-containing paste can be appropriately designed depending on the paste composition, and are preferably, for example, 120 to 150°C for about 5 minutes.

[0074] <Process (X3)> Next, the outer glass sheet 11 and the inner glass sheet 13 after the above process are heated simultaneously or individually to a temperature above their softening points (e.g., 600 to 700°C) to bend each glass sheet. In this process, the ceramic paste layer BLP and the conductive paste layer 20P are simultaneously fired to form the light-shielding layer BL2, and optionally the light-shielding layer BL4, and the conductor 20. After firing, each glass sheet is slowly cooled. After the above steps, as shown in FIG. 4B, a conductor-attached glass plate 11Y and an inner glass plate 13 which may have a light-shielding layer BL4 are obtained.

[0075] (Lamination process) The method for manufacturing a vehicle window glass of the present embodiment may include a laminating step between the step (X) and the step (Y). As shown in FIG. 4C, the conductor-attached glass plate 11Y and the inner glass plate 13 which may have a light-shielding layer BL4 are bonded together via a resin film 12F made of the material of the interlayer 12. The resin constituting the resin film 12F is not particularly limited, and is preferably one or more resins selected from the group consisting of polyvinyl butyral (PVB), ethylene vinyl acetate copolymer (EVA), cycloolefin polymer (COP), polyurethane (PU), and ionomer resin. The resin film 12F may contain one or more additives other than resins as needed. Examples of additives include colorants such as pigments. The resin film 12F may be colorless and transparent or colored and transparent. The resin film 12F may have a single-layer structure or a laminate structure of two or more layers.

[0076] The lamination can be performed by thermocompression bonding. Examples of thermocompression bonding methods include a method in which a temporary laminate obtained by stacking multiple members as shown in Figure 4C is placed in a bag made of rubber or the like and heated in a vacuum; a method in which the temporary laminate is pressed using a roller while being heated; a method in which the temporary laminate is pressurized and heated using an automatic pressure and heat treatment device, an autoclave, or the like; and a combination of these methods. The thermocompression bonding conditions of temperature, pressure, and time are not particularly limited and are designed according to the type and temperature of the resin film 12F. The thermocompression bonding conditions may be any conditions that allow the resin film 12F to soften, be sufficiently pressurized, and sufficiently bond the conductor-attached glass plate 11Y and the inner glass plate 13, which may have a light-shielding layer BL4, via the resin. Thermocompression bonding may be performed in multiple stages using different methods or conditions. The constituent resin of the resin film 12F softens and spreads to fill the space between the conductor-attached glass plate 11Y and the inner glass plate 13 which may have the light-shielding layer BL4.

[0077] The lamination process can include, for example, a preliminary pressure-bonding process in which the pre-pressure-bonded body is heated under reduced pressure at a temperature lower than the heating temperature in the subsequent final pressure-bonding process, and a final pressure-bonding process in which the pre-pressure-bonded body is heated under pressure at a temperature of 100 to 150°C. In the preliminary pressure-bonding step, for example, the temporary laminate is placed in a bag made of rubber or the like, and heated under reduced pressure at a pressure inside the bag of approximately -65 to -100 kPa (absolute pressure of approximately 36 to 1 kPa) at a temperature in the range of 60 to 110°C, which is lower than the heating temperature in the subsequent main pressure-bonding step. The heating temperature is preferably 60 to 100°C. The heating time is preferably 5 to 30 minutes. Here, the "heating time in the preliminary pressure-bonding step" refers to the time during which the temperature is maintained at 60 to 110°C, and does not include the time for heating and cooling. In the main pressure bonding step, for example, the pre-pressure bonded body obtained can be placed in an autoclave and heated under pressure at a pressure of approximately 0.98 to 1.47 MPa and a temperature of 100 to 150°C. The heating temperature is preferably 110 to 150°C, more preferably 120 to 150°C. The heating time is preferably 20 to 40 minutes. The "heating time in the main pressure bonding step" referred to here means the time during which the temperature is maintained at 100 to 150°C, and does not include the time for heating and cooling. After the above steps, a laminated glass 10 is obtained as shown in FIG. 4D.

[0078] (Process (Y)) Next, as shown in Fig. 4E, terminals 102 are joined to terminal joints 20T of each power supply electrode 20B via lead-free solder 101. At least the terminal joints 20T of each power supply electrode 20B are preferably surface-polished in advance by a known method using a sand eraser or the like. Power supply members 103, preferably made of round or foil-shaped conductive wires, are fixed (preferably by crimping) to terminals 102 in advance by a known method.

[0079] The soldering can be performed by a known method, preferably using a soldering iron or resistance heating. When using a soldering iron, the joining can be performed, for example, as follows. A lead-free solder tip is attached to each solder joint of the terminal. The amount of the lead-free solder tip is preferably 0.02 to 0.10 g. The lower limit is more preferably 0.03 g, and particularly preferably 0.05 g. The upper limit is more preferably 0.09 g, and particularly preferably 0.08 g. Before attaching the lead-free solder chip to each solder joint of the terminal, it is recommended to apply flux to the surface of the lead-free solder chip and / or the surface of the solder joint of the terminal in advance. The flux dissolves the metal oxide film, resulting in a good joint. It is recommended to place an appropriate amount of lead-free solder on the tip of the soldering iron and heat it to melt. This solder is called pre-solder and can improve thermal conductivity during soldering. The terminal with the lead-free solder tip attached is placed on the terminal joint of the conductor. In this state, preferably pre-solder is applied to the solder joint of the terminal, and the tip of a soldering iron set to a temperature above the melting point of the lead-free solder is pressed against it to heat and melt the lead-free solder tip. Then, the soldering iron is removed from the terminal, and the lead-free solder is allowed to solidify by natural cooling.

[0080] The shape of the lead-free solder tip used for soldering is not particularly limited. Conventionally, solder chips used for solder bonding in vehicle window glass have generally been block-shaped or plate-shaped solder chips having a first plane that makes surface contact with a terminal and a second plane that makes surface contact with a conductor (see, for example, Claim 1 of JP 2016-64444 A, Figures 4 and 5 of JP 2020-77468 A, etc.).

[0081] A first embodiment of the lead-free solder chip is a dome-shaped or similar lead-free solder chip C1, as shown in Fig. 5A, having a flat surface PS1 that makes surface contact with the terminal 102 and a convex curved surface CS1 that makes contact with the conductor 20. As shown in Fig. 5A, preferably, flux FL can be applied to the convex curved surface CS1 of the lead-free solder chip C1. As shown in FIG. 5B, a pair of lead-free solder chips C1 are placed on each terminal joint 20T (each power supply electrode 20B) of the conductor 20, and a terminal 102 is placed on the pair of placed lead-free solder chips C1. At this time, the flat surface PS1 of the lead-free solder chip C1 is brought into contact with the solder joint 102B of the terminal 102, and the convex curved surface CS1 of the lead-free solder chip C1 is brought into contact with the surface of the terminal joint 20T (power supply electrode 20B) of the conductor 20. In this state, preferably pre-solder is applied to each solder joint 102B of the terminal 102, and the tip of a soldering iron (not shown) set to a temperature equal to or higher than the melting point of the lead-free solder chips C1 is pressed against the solder joint 102B to heat and melt the lead-free solder chips C1.

[0082] The flux FL applied to the surface of the lead-free solder chip C1 reacts with the oxide film formed on the surface of the conductor 20 to produce water. The organic solvent contained in the flux FL and liquid components such as water produced by the reaction between the flux FL and the oxide film are vaporized by heating. As shown in Figure 5C, in a dome-shaped or similar lead-free solder chip C1 having a flat surface PS1 that makes surface contact with the terminal 102 and a convex curved surface CS1 that makes contact with the conductor 20, the contact area between the lead-free solder chip C1 and the conductor 20 can be reduced from the start of heating the lead-free solder chip C1 until it melts, which is thought to facilitate the evaporation of vaporized liquid component G from the sides of the lead-free solder chip C1. Furthermore, when the soldering iron is applied to the terminal 102, heat is transferred from the terminal 102 side (top in the figure) to the outer glass plate 11 side (bottom in the figure), which is thought to facilitate the evaporation of vaporized liquid component G. In Figure 5C, the evaporation of vaporized liquid component G is schematically shown by the dashed-dotted arrows. 5A to 5C are schematic cross-sectional views corresponding to FIG. 5D.

[0083] The heated and melted lead-free solder spreads to fill the space between the conductor 20 and the terminal 102. Thereafter, the soldering iron is removed from the terminal 102, and the lead-free solder is allowed to solidify by natural cooling. In this manner, a laminated structure of terminal 102 / lead-free solder 101 / power supply electrode 20B / light-shielding layer BL2 / outer glass plate 11 can be formed as shown in FIG. 5D. In the method using a dome-shaped or similar lead-free solder tip C1 having a flat surface PS1 that makes surface contact with the terminal 102 and a convex curved surface CS1 that makes contact with the conductor 20, the vaporized liquid component G is easily released, making it difficult for voids to remain in the lead-free solder 101, effectively reducing the porosity of the terminal-side surface (terminal bonding surface) 101S of the lead-free solder 101. As a result, the terminal bonding strength can be increased after durability tests such as high-temperature / high-humidity tests and thermal cycle tests.

[0084] A second embodiment of the lead-free solder chip is a block- or plate-shaped lead-free solder chip C2, as shown in Fig. 6A, which has a first flat surface PS1 that makes surface contact with the terminal 102 and a second flat surface PS2 that makes contact with the conductor 20. As shown in Fig. 6A, flux FL can preferably be applied to the second flat surface PS2 of the lead-free solder chip C2. 6B, a pair of lead-free solder chips C2 are placed on each terminal joint 20T (each power supply electrode 20B) of the conductor 20, and a terminal 102 is placed on the pair of placed lead-free solder chips C2. At this time, a first flat surface PS1 of the lead-free solder chip C2 is brought into contact with the solder joint 102B of the terminal 102, and a second flat surface PS2 of the lead-free solder chip C2 is brought into contact with the surface of the terminal joint 20T (power supply electrode 20B) of the conductor 20. In this state, preferably pre-solder is applied to each solder joint 102B of the terminal 102, and the tip of a soldering iron (not shown) set to a temperature equal to or higher than the melting point of the lead-free solder chip C2 is pressed against the solder joint 102B to heat and melt the lead-free solder chip C2.

[0085] The flux FL applied to the surface of the lead-free solder chip C2 reacts with the oxide film formed on the surface of the conductor 20 to produce water. The organic solvent contained in the flux FL and liquid components such as water produced by the reaction between the flux FL and the oxide film are vaporized by heating. As shown in Figure 6C, in a block- or plate-shaped lead-free solder chip C2 having a first flat surface PS1 that makes surface contact with terminal 102 and a second flat surface PS2 that makes contact with conductor 20, when heating of lead-free solder chip C2 begins, the contact area between lead-free solder chip C2 and conductor 20 is large, and the flux FL is completely sandwiched between lead-free solder chip C2 and conductor 20, making it difficult for vaporized liquid component G to escape from the sides of lead-free solder chip C2. Vaporized liquid component G that cannot escape to the outside is thought to remain within lead-free solder 101 as voids. In Figure 6C, the escape of vaporized liquid component G is schematically shown by the dashed-dotted arrows. The heated and melted lead-free solder spreads to fill the space between the conductor 20 and the terminal 102. Thereafter, the soldering iron is removed from the terminal 102, and the lead-free solder is allowed to solidify by natural cooling. In this manner, a laminated structure of terminal 102 / lead-free solder 101 / power supply electrode 20B / light-shielding layer BL2 / outer glass plate 11 can be formed as shown in FIG. 6D. 6A to 6D are schematic cross-sectional views corresponding to FIG. 5D.

[0086] Generally, to achieve a good bond between a conductor and lead-free solder, an alloy layer containing an alloy of one or more metal elements contained in the conductor and multiple metal elements contained in the lead-free solder must be formed at the bonding interface between the conductor and lead-free solder. Therefore, the solder is heated to above its melting point to achieve solder bonding. The melting point of lead-free solder such as SnAg-based and SnAgCu-based solder is, for example, about 220°C, and in this case, the soldering temperature is preferably, for example, about 300°C. The melting point of In-based lead-free solder is about 100 to 150°C, and in this case, the soldering temperature is preferably, for example, about 250°C. The terminals 102 are sealed with a resin such as silicone resin by a known method, if necessary. In this manner, the vehicle window glass 1 is manufactured.

[0087] [Design modification example of the first embodiment] In the first embodiment, the conductor 20 includes an electrical function part made of one or more heating wires 20L or heating layers, and a power supply part including a pair of power supply electrodes (a pair of bus bars) 20B. The conductor 20 may include only a power supply part without including an electrical function part, and this power supply part may be connected to an electrical function part that is not included in the conductor 20.

[0088] For example, as shown in Fig. 7, a conductor 30 including an electrical function portion can be formed on a resin film 12F made of the material of the intermediate film 12. For example, the conductor 30 can include an electrical function portion made of one or more heating wires or layers, and can further include a power supply portion including a pair of power supply electrodes (a pair of bus bars) as needed. In Fig. 7, the same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted. For example, one or more metal wires (e.g., tungsten wires) as one or more heating wires and, if necessary, a pair of metal foils (e.g., copper foils) as a pair of power supply electrodes (bus bars) can be arranged on resin film 12F. Alternatively, a resin film (e.g., a polyethylene terephthalate (PET) film) having one or more heating wires and a pair of power supply electrodes formed on its surface can be arranged on resin film 12F.

[0089] The electrical function part formed on the resin film 12F is connected to the conductor 20 consisting only of a power supply part included in the conductor-attached glass plate 11Y after the conductor-attached glass plate 11Y and the inner glass plate 13 are bonded together via the interlayer film 12. The electrical function part formed on the resin film 12F may be connected to the conductor 20 consisting only of a power supply part included in the conductor-attached glass plate 11Y via the power supply part formed on the resin film 12F. The configuration, material, forming method, pattern and forming area of ​​the conductor 30 formed on the resin film 12F, which includes an electrical functional part and, if necessary, a power supply part, and the conductor 20 consisting only of a power supply part included in the conductor-attached glass plate 11Y, can be designed as appropriate.

[0090] In this modified design example, similarly to the first embodiment, a light-shielding layer BL2 can be formed between the outer glass plate 11 and the terminal joint portion 20T. In this design modification example, as shown in Figure 7, after manufacturing laminated glass by bonding a conductor-equipped glass plate 11Y and an inner glass plate 13 via an intermediate film 12, a process (Y) can be carried out in which a terminal 102 is joined to the terminal joint portion 20T of each power supply electrode 20B via lead-free solder 101.

[0091] [Second embodiment] The structure of a vehicle window glass according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 8A is an overall plan view of a vehicle window glass of this embodiment. FIG. 8B is a partially enlarged plan view of FIG. 8A. FIGS. 8A and 8B are views before terminal joining. In FIGS. 8A and 8B, the front side of the illustrations is the interior side of the vehicle, and the back side of the illustrations is the exterior side of the vehicle. FIG. 9A is a cross-sectional view taken along line IXA-IXA of FIG. 8A. FIG. 9B is a cross-sectional view taken along line IXB-IXB of FIG. 8A. FIG. 9C is a cross-sectional view taken along line IXC-IXC of FIG. 8A. In FIGS. 9A to 9C, the upper side of the illustrations is the exterior side of the vehicle, and the lower side of the illustrations is the interior side of the vehicle. These figures are all schematic views, and for ease of viewing, the scale of each component in each drawing has been appropriately changed from the actual scale. The same reference symbols have been used for the same components as in the first embodiment, and explanations thereof will be omitted where appropriate.

[0092] The planar shape of the vehicle window glass 2 can be designed as appropriate, and examples thereof include a shape in which a plate having a generally trapezoidal shape in plan view is curved as a whole, as shown in FIG. 8A. As shown in FIG. 9C, the vehicle window glass 2 of this embodiment is a windshield or rear glass including a laminated glass 50 in which an outer glass sheet 11 (a glass sheet on the outside of the vehicle) and an inner glass sheet 13 (a glass sheet on the inside of the vehicle) are bonded together via an interlayer film 12.

[0093] In this embodiment, the laminated glass 50 includes an inner glass sheet 13, a terminal-equipped glass sheet 13X formed on the vehicle interior surface S4 (the surface opposite the interlayer film 12) of the inner glass sheet 13 and made of a material containing silver and glass frit, the conductor 60 having a terminal joint 60T to which a terminal 102 is joined, and the terminal 102 joined to the terminal joint 60T of the conductor 60 via lead-free solder 101. The laminated glass may be made by bonding three or more glass sheets together.

[0094] As shown in FIG. 8A, the vehicle window glass 2 has an optical device mounting area OP where an optical device is mounted, and a light-transmitting portion TP located within the optical device mounting area OP and through which incident light from the outside to the optical device and / or emitted light from the optical device passes. As shown in the figure, the light-transmitting portion TP can be formed in a region relatively close to one end side 50E of the vehicle window glass 2 (the upper end side in the illustrated example).

[0095] The optical device may include, for example, optical equipment such as an ADAS (Advanced Driver Assistance systems) camera, LiDAR (Light Detection And Ranging), radar, and optical sensors that acquire information in front of or behind the vehicle for the purposes of autonomous driving and preventing collision accidents, and a housing called a bracket or the like that houses these. The shapes of the optical device mounting area OP and the light-transmitting portion TP can be appropriately designed to match the shape of the optical device, and examples thereof include a substantially trapezoidal shape and a substantially rectangular shape. The shapes of the optical device mounting area OP and the light-transmitting portion TP may be similar or dissimilar. In the illustrated example, the shapes of the optical device mounting area OP and the light-transmitting portion TP are substantially trapezoidal.

[0096] As in the first embodiment, as shown in Fig. 8A, the vehicle window glass 2 of this embodiment can have one or more light-shielding layers BL in an area including the peripheral area. The light-shielding layers BL can contain a black pigment and glass frit. The number of light-shielding layers BL, the glass surface on which the light-shielding layers BL are formed, and the areas where the light-shielding layers BL are formed can be designed as appropriate.

[0097] 9C, in this embodiment, a light-shielding layer BL4 is formed in a predetermined region on the vehicle interior surface S4 (the surface opposite to the intermediate film 12 side) of the inner glass sheet 13. Most of the conductor 60 is formed on this light-shielding layer BL4. As shown in FIG. 8A, the formation area of ​​the light-shielding layer BL4 can include the area excluding the light-transmitting portion TP from the optical device mounting area OP, the area around the optical device mounting area OP, and the peripheral area of ​​the vehicle window glass 2. In the illustrated example, the formation area of ​​the light-shielding layer BL4 includes the area excluding the light-transmitting portion TP from the optical device mounting area OP and the area surrounding the optical device mounting area OP, and also includes an area R41 excluding the light-transmitting portion TP from an approximately trapezoidal area outlined by one end edge 50E (the upper end edge in the illustrated example) of the laminated glass 50 and edges B41 to B43, and a peripheral area R42 of the vehicle window glass 2. In the illustrated example, the light-shielding layer BL4 surrounds all four sides of the light-transmitting portion TP, but it is sufficient that the light-shielding layer BL4 surrounds at least a portion of the light-transmitting portion TP, and for example, it may surround only three sides of the light-transmitting portion TP which is approximately trapezoidal or approximately rectangular. The wavelength range of light transmitted through the light-transmitting portion TP is not particularly limited, and may be, for example, the visible light range, the infrared light range, or a range from the visible light range to the infrared light range.

[0098] 9C , if necessary, a light-shielding layer BL2 can be formed on the vehicle interior surface S2 of the exterior glass sheet 11. The formation region of the light-shielding layer BL2 can include, for example, the region of the optical device mounting region OP excluding the light-transmitting portion TP, the region around the optical device mounting region OP, and the peripheral region of the vehicle window glass 2, similar to the light-shielding layer BL4. The planar shape of the region R21 of the light-shielding layer BL2 and the planar shape of the region R41 of the light-shielding layer BL4 can be designed independently, and the planar shapes of these regions may be the same or different.

[0099] 8B, in this embodiment, the conductor 60 includes an electrical function unit made of a heating wire 60L formed inside the translucent portion TP. The conductor 60 further includes a power supply unit made of a pair of power supply electrodes (a pair of bus bars) 60B formed outside the translucent portion TP. The conductor 60 further includes two connection wires 60M formed outside the translucent portion TP and connecting the heating wire 60L and the pair of power supply electrodes (a pair of bus bars) 60B.

[0100] By providing an electric heating wire 60L for preventing fogging and frost in an area including a light-transmitting portion TP located in front of optical equipment such as a camera and radar included in the optical device, the sensing accuracy of the optical device can be improved. The number of heating wires 60L, the number of connecting wires 60M, the number of power supply electrodes 60B, the line pattern and arrangement pattern of the heating wires 60L and connecting wires 60M, the shape and arrangement pattern of the power supply electrodes 60B, etc. can be designed as appropriate. For example, when viewed from above, it is preferable that the heating wire 60L is folded back so as to cross the light-transmitting portion TP multiple times or more, since this allows frost and water droplets adhering to the light-transmitting portion TP to be efficiently removed. The width of the heating wire 60L and / or the connecting wire 60M from one power supply electrode to the other power supply electrode may be substantially the same or may vary.

[0101] As shown in FIG. 9C, in this embodiment, the conductor 60 is formed on the vehicle interior surface S4 of the inner glass sheet 13. As in the first embodiment, each of the pair of power supply electrodes (pair of bus bars) 60B includes a terminal joint portion 60T, and a terminal 102 is joined to the terminal joint portion 60T of the conductor 60 via lead-free solder 101. A power supply member 103 made of a round or foil-shaped conducting wire is fixed to the terminal 102. As in the first embodiment, the terminal joint 60T of the conductor 60 is the portion directly below the lead-free solder 101. In the drawing, the area of ​​the terminal joint 60T is the area sandwiched between two dashed lines T1 and T2. Note that the position of the terminal joint 60T of the conductor 60 is not clearly determined from the beginning. In the power supply electrode 60B, the portion directly below the lead-free solder 101 after the terminal 102 is joined via the lead-free solder 101 is the terminal joint 60T. The partially enlarged cross-sectional view of the cross section of the laminated structure of terminal 102 / lead-free solder 101 / power supply electrode 60B / light-shielding layer BL4 / inner glass plate 13 as viewed from the left in FIG. 9C is similar to FIG. 5D.

[0102] As shown in FIGS. 8B and 9A, in this embodiment, the light-shielding layer BL is not formed in the light-transmitting portion TP. 8B, 9B, and 9C, the connection wiring 60M and the power supply portion of the conductor 60 included in the terminal-equipped glass plate 13X are preferably formed on the light-shielding layer BL4. In this configuration, the connection wiring 60M and the power supply portion of the conductor 60 included in the terminal-equipped glass plate 13X can be designed so that they are not visible to people outside the vehicle. In the manufacturing method of the present disclosure, the terminal bonding strength of the terminal-equipped glass plate 13X can be improved, and therefore the terminal-equipped glass plate 13X can have a light-shielding layer BL4 between the inner glass plate 13 and the terminal bonding portion 60T.

[0103] In this embodiment, the porosity of the terminal-side surface (terminal bonding surface) 101S of the lead-free solder 101 (see FIG. 5D) is 15% or less. The upper limit is preferably 12%, more preferably 10%, particularly preferably 8%, and most preferably 5%. The lower limit is not particularly limited, and is, for example, 0.1%. By setting the porosity of the terminal side surface (terminal bonding surface) 101S of the lead-free solder 101 to the above upper limit or less, the terminal bonding strength after durability tests such as high temperature and high humidity tests and thermal cycle tests can be effectively increased.

[0104] (Manufacturing method) An example of a method for manufacturing a vehicle window glass according to this embodiment will be described. The method for manufacturing the vehicle window glass 2 of this embodiment is as follows: a step (X) of preparing a conductor-equipped glass sheet 13Y in which a conductor 60 is formed on the vehicle exterior surface S4 of the inner glass sheet 13; and a step (Y) of joining a terminal 102 onto the terminal joining portion 60T of the conductor 60 via lead-free solder 101.

[0105] (Process (X)) The step (X) can include the following steps (X1) to (X3).

[0106] <Process (X1)> First, a ceramic paste containing black pigment and glass frit, which are materials for the light-shielding layer BL4, is applied to a predetermined area on the vehicle interior surface S4 of the inner glass plate 13 as needed, and dried to form a ceramic paste layer BLP. In addition, if necessary, a ceramic paste containing black pigment and glass frit, which are materials for the light-shielding layer BL2, is applied to a predetermined area on the vehicle interior surface S2 of the outer glass sheet 11 and dried to form a ceramic paste layer BLP. The drying conditions for the ceramic paste layer are the same as those in the first embodiment.

[0107] <Process (X2)> Next, a silver-containing paste containing silver and glass frit, which are materials for the conductor 60, is applied to the vehicle interior surface S4 of the inner glass sheet 13 and dried to form a conductive paste layer 60P. The drying conditions for the conductive paste layer are the same as those in the first embodiment.

[0108] <Process (X3)> Next, the outer glass sheet 11 and the inner glass sheet 13 after the above process are heated to a temperature above their softening points, and each glass sheet is bent. In this process, the ceramic paste layer BLP and the conductive paste layer 60P are simultaneously fired to form the light-shielding layers BL2 and BL4 and the conductor 60. After firing, each glass sheet is slowly cooled. The firing temperature is the same as in the first embodiment. After the above steps, the outer glass plate 11 having the light-shielding layer BL2 and the conductor-attached glass plate 13Y are obtained.

[0109] (Lamination process) The method for manufacturing a vehicle window glass of the present embodiment may include a laminating step between the step (X) and the step (Y). The outer glass plate 11 having the light-shielding layer BL2 and the conductor-attached glass plate 13Y are bonded together via a resin film 12F made of the material of the interlayer film 12. The bonding method is the same as in the first embodiment. After the above steps, a laminated glass 50 is obtained.

[0110] (Process (Y)) Next, a terminal 102 is joined via lead-free solder 101 onto the terminal joint portion 60T included in each power supply electrode 60B. The soldering can be performed in the same manner as in the first embodiment, using a dome-shaped or other lead-free solder chip C1 having a flat surface PS1 that makes surface contact with the terminal 102 and a convex curved surface CS1 that makes contact with the conductor 60, as shown in Figures 5A to 5D. In this method, the contact area between the conductor 60 and the lead-free solder chip C1 is small from the start of heating to melting of the lead-free solder chip C1, which makes it easier for the flux FL to escape during the soldering process and reduces the likelihood of voids remaining in the lead-free solder 101. This effectively reduces the porosity of the terminal-side surface (terminal bonding surface) 101S of the lead-free solder 101. As a result, the terminal bonding strength can be increased after durability tests such as high-temperature / high-humidity tests and thermal cycle tests. In this manner, the vehicle window glass 2 is manufactured.

[0111] [Third embodiment] The structure of a vehicle window glass according to a third embodiment of the present invention will be described with reference to the drawings. Fig. 10 is a partial plan view of the vehicle window glass of this embodiment, showing the state before terminal joining. The vehicle window glass 3 of this embodiment is a windshield or rear glass having a glass plate 70 and a conductor 80 formed on one surface of the glass plate 70, containing silver and glass frit, and having a terminal joint portion to which a terminal is joined. The glass pane 70 can be tempered glass or laminated glass. The conductor 80 includes an antenna for receiving radio waves. The antenna includes one or more antenna wires 80L, and may include multiple types of antenna wires 80L with different patterns and / or lengths depending on the wavelength of the radio waves to be received, as necessary. The antenna includes a power supply portion such as one or more power supply electrodes (bus bars) 80B. Each power supply electrode (bus bar) 80B includes a terminal joint portion to which a terminal is joined. The technology of the present disclosure can also be applied to terminal joining to the power supply electrode (bus bar) 80B connected to the antenna line 80L.

[0112] As described above, the present disclosure can provide a vehicle window glass that includes a portion where a conductor and a terminal are joined using lead-free solder and that can increase the terminal joining strength, and a method for manufacturing the same. [Example]

[0113] The present invention will be described below based on examples, but the present invention is not limited to these. Examples 1 to 3 are examples, and Example 11 is a comparative example.

[0114] [Evaluation items and evaluation methods] The evaluation items and evaluation methods are as follows: (Initial terminal bonding strength) A tensile test was carried out in an environment of room temperature (20 to 30°C) using an autograph (Shimadzu Corporation's "AGS-X", maximum load: load 5kN). The glass plate (11X) with terminals and having a laminated structure as shown in FIG. 5D obtained in each example was set in a testing machine. With the glass plate (11) fixed, the center portion (102P) of the terminal was pulled in a direction perpendicular to the surface of the glass plate (11) (upward in the figure) at a pulling speed of 100 mm / min, and the tensile strength required to peel the terminal (102) from the glass plate (11) was measured as the terminal bond strength. A total of five samples were measured for each condition, and the average value was used as the terminal bond strength data. The data on the initial terminal bonding strength is data on the terminal bonding strength before durability tests such as a high-temperature high-humidity test and a thermal cycle test are carried out.

[0115] (Terminal bonding strength after high temperature and humidity testing) The glass sheets (11X) with terminals having the laminated structure shown in Fig. 5D obtained in each example were subjected to a high-temperature, high-humidity test in which they were stored in an environment of 80°C and 95% relative humidity for 500 hours. After this test, the terminal bonding strength was measured in the same manner as the initial test.

[0116] (Terminal bonding strength after thermal cycle test) For the glass plate (11X) with terminals having the laminated structure shown in Fig. 5D obtained in each example, a thermal cycling test was performed in which the temperature was decreased from 20°C to -40°C at a constant rate over 50 minutes, held at -40°C for 100 minutes, increased from -40°C to 120°C at a constant rate over 150 minutes, held at 120°C for 120 minutes, and decreased from 120°C to 20°C at a constant rate over 60 minutes. This temperature cycle was repeated 60 times. After this test, the terminal bonding strength was measured in the same manner as the initial test.

[0117] (Porosity of the terminal side surface (terminal joint surface) of lead-free solder) After measuring the initial terminal bond strength, a Keyence microscope was used to take an image of the surface (101S) of the lead-free solder (101) exposed by peeling off the terminal (102). In the obtained surface image, the ratio of the total area of ​​one or more voids that may exist inside the lead-free solder to the total area of ​​the lead-free solder and one or more voids that may exist inside the lead-free solder (the area surrounded by the outer periphery of the lead-free solder) was calculated as the "porosity." A total of five samples were measured for each condition, and the average value was used as the porosity data.

[0118] [Production of Evaluation Glass Plate with Light-Shielding Layer and Conductor (Evaluation Glass Plate 1)] A 100 mm x 100 mm square untempered glass plate (G1) (AGC "VFL", green color) having a thickness of 2.0 mm was prepared. A commercially available ceramic paste (BP1) containing a black pigment and glass frit for forming a light-shielding layer was applied to one surface of the glass plate and dried at 120°C for approximately 15 minutes to form a ceramic paste layer. Next, a commercially available silver-containing paste (AgP1) for forming a conductor, which contains silver powder and glass frit, was applied and dried at 120°C for 10 minutes to form a conductive paste layer. The ceramic paste layer and the conductive paste layer were then fired. The temperature was raised from room temperature (20-30°C) to 630°C at a rate of approximately 180°C / min, fired at 630°C for 3 minutes, and then naturally cooled to room temperature (20-30°C). In this way, a light-shielding layer and a conductor were formed.

[0119] The planar shape of the light-shielding layer was a square of 52 mm x 52 mm, and its center and diagonal lines were aligned with the center and diagonal lines of the glass plate. The thickness of the light-shielding layer was about 15 to 17 μm. The conductor had a planar shape of a 50 mm × 50 mm square, with its center and diagonal aligned with the center and diagonal of the glass plate. The conductor had a thickness of approximately 6 to 9 μm. In this manner, evaluation glass plate 1 having a light-shielding layer and a conductor was produced.

[0120] [Example 1] At room temperature (20-30°C), a stainless steel crimp terminal (see Figures 3 and 5D) consisting of a cylindrical power supply member joint (102A) into which the tip of the wire harness (exposed conductor portion) is inserted and a bridge-shaped portion having solder joints (102B) at both ends was joined to the conductor of the obtained evaluation glass plate 1 using a lead-free solder tip. The specific method is as follows.

[0121] As a lead-free solder chip, a dome-shaped lead-free solder chip (C1) was prepared, as shown in Figure 5A, having a flat surface (PS1) that makes surface contact with the terminal (102) and a convex curved surface (CS1) that makes contact with the conductor (20). In this example, the lead-free solder chip (C1) used was a dome-shaped lead-free solder chip made of SnAg-based lead-free solder (Sn: 98% by mass, Ag: 2.0% by mass, melting point: approximately 220°C), measuring 3.0 mm wide, 5.0 mm long, and approximately 1.00 to 1.15 mm in maximum height, weighing 0.03 g. As shown in Figure 5A, flux (FL) was applied to the convex curved surface (CS1) of the lead-free solder chip (C1). A commercially available rosin-based flux (containing ethylbenzene and xylene as organic solvents in a total of 25% by mass) was used as the flux (FL).

[0122] As shown in Figure 5B, a pair of lead-free solder chips (C1) was placed on the conductor (20), and a terminal 102 was placed on the pair of lead-free solder chips (C1). At this time, the flat surface (PS1) of the lead-free solder chip (C1) was brought into contact with the solder joint (102B) of the terminal (102), and the convex curved surface (CS1) of the lead-free solder chip (C1) was brought into contact with the surface of the conductor (20).

[0123] An appropriate amount of lead-free solder (SnAg-based lead-free solder (Sn: 98% by mass, Ag: 2.0% by mass, melting point: approximately 220°C)) was placed on the tip of a soldering iron and heated to melt it. This solder is called pre-solder. Preliminary solder was applied to each solder joint (102B) of the terminal (102), and the tip of a soldering iron set to a temperature higher than the melting point of the lead-free solder chip (C1) was pressed against it to heat and melt the lead-free solder chip (C1).

[0124] The flux (FL) applied to the surface of the lead-free solder chip (C1) reacted with the oxide film formed on the surface of the conductor (20) to produce water. The organic solvent contained in the flux (FL) and the liquid components such as water produced by the reaction between the flux (FL) and the oxide film evaporated when heated. 5C, in the dome-shaped lead-free solder chip (C1) having a flat surface (PS1) that makes surface contact with the terminal (102) and a convex curved surface (CS1) that makes contact with the conductor (20), the contact area between the lead-free solder chip (C1) and the conductor (20) can be reduced from the start of heating to the melting of the lead-free solder chip (C1). Therefore, it is thought that the vaporized liquid component (G) easily escapes from the side of the lead-free solder chip (C1). In addition, since the soldering iron is applied to the terminal (102), heat is transferred from the terminal (102) side to the glass plate (11) side (bottom in the figure), which is thought to facilitate the escape of the vaporized liquid component (G). The heated and melted lead-free solder spread to fill the space between the conductor 20 and the terminal 102. After that, the soldering iron was removed from the terminal 102, and the lead-free solder was allowed to solidify by natural cooling. In this manner, a glass plate with terminals (11X) having a laminated structure of terminals (102) / lead-free solder (101) / conductor (20) / light-shielding layer (BL) / glass plate (11) as shown in FIG. 5D was obtained.

[0125] After one hour had passed since the terminal (102) was joined to the conductor (20) via the lead-free solder (101) and the temperature of the lead-free solder (101) had dropped to room temperature (20 to 30°C), the initial terminal joining strength of the glass plate (11X) with terminal and the porosity of the terminal-side surface (terminal joining surface) (101S) of the lead-free solder (101) were measured. Furthermore, a durability test (high temperature and high humidity test or thermal cycle test) was carried out on the obtained glass plate (11X) with terminals, and the terminal bonding strength after the durability test was measured.

[0126] [Example 2, Example 3] In Example 2, a dome-shaped lead-free solder chip (C1) made of SnAg-based lead-free solder (Sn: 98% by mass, Ag: 2.0% by mass, melting point: approximately 220°C), measuring 3.0 mm in width, 5.0 mm in length, and approximately 1.30 to 1.45 mm in maximum height, weighing 0.05 g, was used. In the same manner as in Example 1, a terminal-equipped glass plate (11X) having a laminated structure of terminal (102) / lead-free solder (101) / conductor (20) / light-shielding layer (BL) / glass plate (11) as shown in FIG. 5D was obtained and evaluated.

[0127] In Example 3, a dome-shaped lead-free solder chip (C1) made of SnAg-based lead-free solder (Sn: 98% by mass, Ag: 2.0% by mass, melting point: approximately 220°C), measuring 3.0 mm in width, 5.0 mm in length, and approximately 1.70 to 1.85 mm in maximum height, weighing 0.08 g, was used. In the same manner as in Example 1, a terminal-equipped glass plate (11X) having a laminated structure of terminal (102) / lead-free solder (101) / conductor (20) / light-shielding layer (BL) / glass plate (11) as shown in FIG. 5D was obtained and evaluated.

[0128] [Example 11] As the lead-free solder chip, a block-shaped lead-free solder chip (C2) was prepared, having a first plane (PS1) that makes surface contact with the terminal (102) and a second plane (PS2) that makes surface contact with the conductor (20), as shown in Figure 6A. In this example, the lead-free solder chip (C2) used was a rectangular (block-shaped) lead-free solder chip made of SnAg-based lead-free solder (Sn: 98% by mass, Ag: 2.0% by mass, melting point: approximately 220°C), 3.2 mm wide, 3.0 mm long, 3.0 mm high, and weighing 0.05 g. In the same manner as in Example 1, except that the block-shaped lead-free solder chip was used as the lead-free solder chip, a glass plate with terminal (11X) having a laminated structure of terminal (102) / lead-free solder (101) / conductor (20) / light-shielding layer (BL) / glass plate (11) was obtained and evaluated, as shown in Figures 6A to 6D.

[0129] [Summary of results] Examples of surface images of the lead-free solder terminal side of the glass sheets with terminals obtained in Examples 1 to 3 are shown in the left image of Figure 11. An example of a surface image of the lead-free solder terminal side of the glass sheet with terminals obtained in Example 11 is shown in the right image of Figure 11. Many relatively large voids were observed in the glass plate with terminals obtained in Example 11. In contrast, relatively large voids were not observed in the glass plates with terminals obtained in Examples 1 to 3, and the size of each void was small.

[0130] The porosity (average porosity for a total of five samples) of the surface (terminal bonding surface) on the terminal side of the lead-free solder of the glass plates with terminals obtained in Examples 1 to 3 was 5% or less. It was confirmed that the method using a dome-shaped lead-free solder tip with a flat surface that makes surface contact with the terminal and a convex curved surface that makes contact with the conductor allows vaporized liquid components to easily escape, effectively reducing the porosity of the lead-free solder.

[0131] The porosity of the terminal-side surface (terminal bonding surface) of the lead-free solder of the glass plate with terminals obtained in Example 11 (average porosity of a total of five samples) was over 15%. With a block-shaped lead-free solder chip having a first flat surface that makes surface contact with the terminal and a second flat surface that makes contact with the conductor, the contact area between the lead-free solder chip and the conductor is large when heating of the lead-free solder chip begins, making it difficult for the vaporized liquid components to escape from the sides of the lead-free solder chip, making it difficult to effectively reduce the porosity of the lead-free solder.

[0132] The evaluation results of the porosity of the terminal-side surface (terminal bonding surface) of the lead-free solder of the glass plate with terminals obtained in each example and the terminal bonding strength are shown in Table 1 and FIGS. 12A to 12C. There was no significant difference in the initial terminal bonding strength between the glass plates with terminals obtained in Examples 1 to 3 and the glass plate with terminals obtained in Example 11. However, the terminal-attached glass plates obtained in Examples 1 to 3, which had low porosity on the terminal-side surface (terminal bonding surface) of the lead-free solder, had high and favorable terminal bonding strength after the durability test (high-temperature, high-humidity test or thermal cycle test).In contrast, the terminal-attached glass plate obtained in Example 11, which had high porosity on the terminal-side surface (terminal bonding surface) of the lead-free solder, had low terminal bonding strength after the durability test (high-temperature, high-humidity test or thermal cycle test).

[0133] [Table 1]

[0134] The present invention is not limited to the above-described embodiments and examples, and various modifications can be made to the design as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0135] 1 to 3: vehicle window glass, 10, 50: laminated glass, 11, 13, 70: glass plate, 11E: exposed portion, 11X, 13X: glass plate with terminal, 11Y, 13Y: glass plate with conductor, 12: interlayer film, 13N: notch, 20, 30, 60: conductor, 20B, 60B, 80B: power supply electrode, 20E: exposed portion, 20L, 60L: heating wire, 80L: antenna wire, 20T, 60T: terminal joint, 101: lead-free solder, 101S: surface of lead-free solder, 102: terminal, 102A: power supply member joint, 102B: solder joint, 103: power supply member, BL: light-shielding layer, OP: optical device mounting area, TP: light-transmitting portion.

Claims

1. A vehicle window glass comprising: a glass plate with a terminal; a conductor formed on one surface of the glass plate, the conductor including silver and glass frit and having a terminal joint portion to which a terminal is joined; and a terminal joined onto the terminal joint portion of the conductor via lead-free solder, The window glass for a vehicle, wherein the porosity of the surface of the lead-free solder on the terminal side is 15% or less.

2. 2. The vehicle window glass according to claim 1, wherein the lead-free solder has a surface on the terminal side with a porosity of 10% or less.

3. The vehicle window glass according to claim 1 or 2, wherein the terminal-equipped glass plate has a light-shielding layer between the glass plate and at least a portion of the electrical conductor including the terminal joint portion.

4. The vehicle window glass according to claim 3 , wherein the light-shielding layer contains a black pigment and a glass frit.

5. 3. The vehicle window glass according to claim 1, wherein the glass plate is tempered glass.

6. a laminated glass in which a plurality of glass plates including the glass plate with terminals are bonded together via an interlayer film, and the conductor is formed on the interlayer film side of the glass plate with terminals, 3. The vehicle window glass according to claim 1, wherein the terminal-equipped glass sheet has an exposed portion that is not covered by the opposing glass sheet with the interlayer film therebetween, and the terminal joint portion of the conductor is formed on the exposed portion.

7. 3. The vehicle window glass according to claim 1, comprising a laminated glass in which a plurality of glass plates including the terminal-equipped glass plate are bonded together via an interlayer film, and the conductor is formed on a side of the terminal-equipped glass plate opposite to a side of the interlayer film.

8. the glass plate with terminals has, in a plan view, an optical device mounting region in which an optical device is mounted, a light-transmitting portion located within the optical device mounting region and through which incident light from the outside to the optical device and / or emitted light from the optical device passes, and a light-shielding layer surrounding at least a portion of the light-transmitting portion in a plan view, 8. The vehicle window glass according to claim 7, wherein the conductor includes a heating wire formed inside the light-transmitting portion, a power supply portion formed outside the light-transmitting portion, and connection wiring formed outside the light-transmitting portion and connecting the heating wire and the power supply portion.

9. The vehicle window glass according to claim 8 , wherein in the terminal-equipped glass plate, the connection wiring and the power supply portion are formed on the light-shielding layer.

10. the electrical conductor includes an electrical function or is electrically connected to an electrical function; the conductor includes a power supply portion for supplying power to the electrical function portion, the power supply portion including the terminal joint portion; 3. The vehicle window glass according to claim 1, wherein a power supply member made of a round or foil conductor is fixed to the terminal.

11. a step (X) of preparing a conductor-attached glass plate in which the conductor is formed on the surface of the glass plate; and a step (Y) of joining the terminal to the terminal joint portion of the conductor via lead-free solder, Step (Y) is A step (Y1) of preparing lead-free solder having a flat surface and a convex curved surface opposite to the flat surface; and a step (Y2) of heating and melting the lead-free solder in a state in which the flat surface of the lead-free solder is in contact with the terminal and the convex curved surface of the lead-free solder is in contact with a surface of the terminal joint portion of the conductor.

12. Step (X) is a step (X2) of applying a silver-containing paste containing silver as a material for the conductor and glass frit onto the surface of the glass plate to form a silver-containing paste layer; and a step (X3) of firing the silver-containing paste layer to form the conductor.

13. Step (X) is a step (X1) of applying a ceramic paste containing a black pigment and glass frit as materials for a light-shielding layer onto the surface of the glass plate to form a ceramic paste layer; a step (X2) of applying a silver-containing paste containing silver as a material for the conductor and glass frit onto the surface of the glass plate to form a silver-containing paste layer; 12. The method for manufacturing a vehicle window glass according to claim 11, further comprising: a step (X3) of firing the ceramic paste layer and the silver-containing paste layer to form the light-shielding layer and the conductor.

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