WO2025188281A1

WO2025188281A1 - A laminated windshield with an opaque layer

Info

Publication number: WO2025188281A1
Application number: PCT/TR2025/050202
Authority: WO
Inventors: Cagatay SUNER; Evrim GUNDUZ TULUMEN; Burcu OGUT
Original assignee: Turkiye Sise Ve Cam Fabrikalari AS
Current assignee: Turkiye Sise Ve Cam Fabrikalari AS
Priority date: 2024-03-06
Filing date: 2025-03-05
Publication date: 2025-09-12
Anticipated expiration: 2026-09-06
Also published as: WO2025188281A8; TR2024002710A2

Abstract

The invention relates to a laminated windshield comprising an outer panel (10), an inner panel (20), and a thermoplastic interlayer (30) that bonds the outer panel (10) to the inner panel (20), separating the vehicle interior from the external environment. The windshield further comprises a conductive layer (40) provided on a first surface (12) of the outer panel (20) facing the inner panel (10), a first terminal (1) and at least one second terminal (2) spaced apart so as to complete a circuit with the conductive layer (40), and an opaque layer (50) provided on the conductive layer (40) in such a way as to mask the first and second terminals (1, 2) without preventing the electrical connection between them.

Description

A LAMINATED WINDSHIELD WITH AN OPAQUE LAYER

TECHNICAL FIELD

The present invention relates to a laminated windshield with an opaque layer.

STATE OF THE ART

In the technical field, particularly for motor vehicle windshields, it is important that they be heated quickly and effectively. The viewing area and the wiper area need to be heated separately and efficiently. The heating process is carried out by passing electric current through a metal coating having nanometric thickness and light transmittance, preferably containing silver, and preferably applied onto the transparent material (which is preferably glass), causing it to heat up by means of the coating’s resistance. The application is performed by supplying energy to a pair of bus bars, which are almost parallel to each other, along opposite edges of the transparent windshield area that needs to be heated. The energy fed to the glass enters at the (+) terminal, flows over the conductive transparent coating, and exits at the (-) terminal. As the current passes through the coating, the coating heats up due to its resistance and thus heats the glass.

A typical malfunction of heated glass is usually the overheating of the coating or the bus bar. Overheating may result from passing current through a defective or damaged bus bar. Furthermore, a break or gap in the conductive film may cause sparking and lead to overheating. In addition, the relative position and length of the bus bars can affect the passage of current through the conductive coating and may create locally elevated temperature regions or “hot spots” in the transparency. Hot spots typically arise when the opposite bus bars are not of equal length, causing increased current flow from the longer bus bar toward the shorter one. Automotive windshields are often trapezoidal in shape, and in order to heat the lower side areas of the windshield, the bottom bus bar is extended to these areas. Consequently, the length of the bottom bus bar’s main rail is longer than that of the top bus bar’s main rail, and hot spots form near the ends of the top bus bar. Overheating and sparking may damage the plastic interlayer or, in severe cases, damage the laminated transparency. TR2023010989 discloses a laminated windshield coated with an electrical conductor. The subject matter invention is a heated windshield that comprises a transparent glass substrate, a conductive coating layer provided on the glass substrate, a first bus bar with a first pole extending transversely at an upper portion of the coating layer, a second bus bar with a second pole opposite the first pole and extending transversely at a lower portion of the coating layer, and a conductive line extending transversely between the first and second bus bars that divides the coating layer into a transparent region and a wiper region. Its feature is that comprises a first circuit that has a first wiper region formed by the second bus bar, the conductive line, and the coating layer extending between them, wherein the first wiper region and the transparent region are heated, at least one second circuit in series with the first circuit that has at least one second wiper region formed by the second bus bar, the conductive line, and the coating layer extending between them, wherein the second wiper region and the transparent region are heated and at least one cut line provided to interrupt electrical conduction so as to separate the first and/or second circuit through which current passes.

SUMMARY OF THE INVENTION

The object of the invention is to provide a laminated windshield with an opaque layer.

In order to achieve the aforementioned objective, the invention relates to a laminated windshield that includes an outer panel, an inner panel, and a thermoplastic interlayer that bonds the outer panel and the inner panel together, thereby separating the vehicle interior from the external environment. The windshield comprises a conductive layer provided on a second surface of the outer panel facing the inner panel, a first terminal and at least one second terminal spaced apart from each other so as to complete a circuit with the conductive layer and an opaque layer provided on the conductive layer in such a way that it masks the first and second terminals without preventing their electrical connection. Thus, by using the opaque layer, it becomes possible to conceal the appearance of the conductive layer and the terminal connections required to heat the laminated windshield, thereby preserving the aesthetic appearance of the glass while enhancing its functionality. Moreover, because it is provided on the second surface, the glass can be heated from the outside surface, eliminating the need for heat conduction through the interlayer and ensuring that the outer panel is heated.

In a preferred embodiment of the invention, there is a first bus bar and a second bus bar that at least partially surround the opaque layer and provide electrical conduction between the first and at least one second terminal and the conductive layer. In this way, continuity is maintained between the conductive layer and the terminal connections necessary to heat the laminated windshield, thus acting as a circuit completer.

In a preferred embodiment of the invention, the first and second bus bars comprises silver. Thus, by using silver, electrical current is conducted very efficiently, reducing energy loss and improving the performance of electromagnetic components.

In a preferred embodiment of the invention, the first and second bus bars have a patterned structure. This increases optical transmittance.

In a preferred embodiment of the invention, the first and second bus bars have a dotted patterned structure. As a result, electricity and heat conduction are transmitted from the silver to the conductive layer.

In a preferred embodiment of the invention, the first terminal and the second terminal are provided on opposite ends of the conductive coating, and the first terminal and the second terminal are oppositely charged. In this way, a specific potential difference is created between the terminals, enabling the electrical energy to be distributed effectively across the conductive coating.

In a preferred embodiment of the invention, the first terminal and the second terminal are located on a top edge and a bottom edge, respectively, opposite each other. Thus, the potential difference between the two terminals can be maintained at the desired level.

In a preferred embodiment of the invention, the conductive layer extends across the entire width of the second surface. In this way, electrical conduction across the glass is achieved along its full span.

In a preferred embodiment of the invention, the opaque layer is an enamel black paint layer. Thus, it prevents the terminal connections from being visible from the outside surface.

In a preferred embodiment of the invention, the outer panel and the inner panel have a curved (bowed) structure. Through their curved shapes, they help improve airflow, thereby enhancing the aerodynamic performance of the vehicle, reducing air resistance during driving, and improving fuel efficiency. In a preferred embodiment of the invention, the outer panel and the inner panel are laminated glass. In this way, a windshield structure meeting high automobile standards for structural strength can be achieved.

In a preferred embodiment of the invention, the outer panel and the inner panel have a thickness ranging from 0.3 to 2.7 mm. In this way, a windshield structure meeting high automobile standards for structural strength can be achieved.

In a preferred embodiment of the invention, direct current is supplied from an electrical source to the first terminal and the at least one second terminal. Thus, the necessary current can be provided from the vehicle’s own power supply. Furthermore, no current converter is required.

In a preferred embodiment of the invention, the thermoplastic interlayer contains PVB. By using PVB, it prevents the glass from shattering upon impact by keeping the outer and inner panels together, thereby reducing the risk of injury.

In a preferred embodiment of the invention, a buffer region is formed on the second surface between the interlayer and the external environment. Thus, with the buffer region formed, it remains unaffected by the external environment, thereby maintaining continuity of heat conduction.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a sectional representation of the windshield subject to the invention.

Figure 2 is a schematic representation of the windshield subject to the invention.

Figure 3 is a schematic representation of the patterned structure of the first and second bus bars included in the windshield subject to the invention.

Figure 4 is a schematic representation of the patterned structure of the first and second bus bars included in the windshield subject to the invention.

DETAILED DESCRIPTION OF THE INVENTION In this detailed description, the development according to the invention is described with reference to examples, without imposing any limitation, and only to better explain the subject matter.

Figure 1 shows the windshield subject to the invention in section. The windshield preferably has at least about 50% visible transmittance, more preferably at least about 60%, and even more preferably at least about 65% or at least about 70%. The windshield separates the vehicle interior from the external environment and have an outer panel (10) and an inner panel (20), which is spaced apart from the outer panel (10). A thermoplastic interlayer (30) that bonds the outer panel (10) to the inner panel (20) is provided. The interlayer (30) contains PVB. The interlayer (30) has a thickness of at least 0.38 mm. The outer panel (10) and the inner panel (20) have a thickness in the range of 0.3 to 2.7 mm and have a curved structure. The surface of the outer panel (10) facing the inner panel (20) is selected as a second surface (14), and the surface facing the external environment is selected as a first surface (12). The second surface (14) of the outer panel (10) is covered by a conductive layer (40) extending lengthwise across it. An opaque layer (50) is provided on the conductive layer (40). The opaque layer (50) contains black enamel paint and has a thickness of at least 10 microns. A first bus bar (60) is placed on the opaque layer (50) so as to enable electrical conduction. The first bus bar (60) extends at least partially along a bottom surface (66) over the opaque layer (50) and contacts the conductive layer (40) at a first edge (62). A second edge (64) is provided opposite the first edge (62) that contacts the conductive layer (40). The first bus bar (60) surrounds the opaque layer (50) along the first and second edges (62, 64). The first bus bar (60) consists of 50% to 90% by weight of silver. A first terminal (1), to which the direct current from a power source (80) is supplied, is provided on an upper surface (68) of the first bus bar (60). The current entering via the first terminal (1) is conducted to the conductive layer (40) by means of the first bus bar (60), providing a flow of electric current over the windshield. The direct current entering the first terminal (1 ) leaves the windshield through a second terminal (2) located on the windshield. A second bus bar (70), which is connected on its upper surface (78) to the second terminal (2), is provided in parallel with the first bus bar (60). The second bus bar (70) extends at least partially along a bottom surface (76) over the opaque layer (50) and contacts the conductive layer (40) at a first edge (72). A second edge (74) is provided opposite the first edge (72) that contacts the conductive layer (40). The second bus bar (70) surrounds the opaque layer (50) along its first and second edges (72, 74). The second bus bar (70) consists of 50% to 90% by weight of silver. A thermoplastic interlayer (30) extends between the second surface (14) of the outer panel (10) and a third surface (22) of the inner panel (20). The surface of the inner panel (20) facing the interior of the vehicle is selected as a fourth surface (24). Figure 2 shows a schematic representation of the windshield subject to the invention. The first and second terminals (1 , 2), shown in Figure 1 , are provided oppositely on an upper edge (3) and a lower edge (4) of the windshield. By creating a specific potential difference between the terminals (1 , 2), electrical energy is effectively distributed across the conductive layer (40). Through the outer panel (10), the inner panel (20), and the thermoplastic interlayer (30), a windshield structure meeting high automobile standards for structural strength is achieved. While the thermoplastic interlayer (30) is provided on the outer panel (10) and the inner panel (20), a buffer region (5) is created by leaving at least 2 mm of clearance. This creates a moisture-based intermediate zone. Since the outer panel (10) and the inner panel (20) have a curved structure, they help improve airflow, thereby enhancing the vehicle’s aerodynamic performance, reducing air resistance during driving, and improving fuel efficiency.

In Figures 3 and 4, schematic representations are shown of the patterned structure of the first and second bus bars (60, 70) included in the windshield subject to the invention. The first and second bus bars (60, 70) have a patterned structure, and these patterns may consist of polygonal shapes or different geometric shapes. Dotted pattern structures are preferred. From a first edge (62, 72) to a second edge (64, 74) of each of the first and second bus bars (60, 70), the pattern density decreases. Reducing the pattern density serves to controllably alter heat and electrical conduction through specific portions of the first and second bus bars (60, 70). By reducing the pattern density, certain viewing areas are prioritized, providing greater transparency at points where external visibility is desired. A density gradient from the first edge (62) to the second edge (64) can be utilized for decorative patterns and brand identity, while also improving functional properties such as electrical and thermal conduction. The first and second bus bars (60, 70) appear in brownish tones from the external environment.

Standard numbering for laminated windshield surfaces is as follows: The outward-facing surface of the outer panel (10) is the first surface (12), the inward-facing surface of the outer panel (10) is the second surface (14), the outward-facing surface of the inner panel (20) is the third surface (22), and the inward-facing surface of the inner panel (20) is the fourth surface (24). The first and fourth surfaces (12, 24) are open to the atmosphere, while the second and third surfaces (14, 22) remain within the lamination and thus are closed to the atmosphere. The windshield has the conductive layer (40) provided on the second surface (14), and an opaque layer (50) printed on the conductive layer (40), which preferably consists of black insulating enamel paint at least 10 mm wide and running all around parallel to the top and bottom edges (3, 4) of the glass. At least two bus bars (60, 70), each composed of 50% to 90% by weight of silver, are applied/printed by the screen-printing method in parallel — where possible — along at least two long edges or at least two short edges of the glass, and they include conductive terminals (1 , 2), attached by an adhesive and/or lead-free solder material, such that the + pole is at the first bus bar (60) and the - pole is at the second bus bar (70). Because the conductive silver bus bars (60, 70) are on the black insulating enamel paint, in order for the conductive bus bars to contact the conductive layer (40) and conduct electricity, part of the bottom surface (66, 76) of the conductive bus bars (60, 70) is over the opaque layer (50), and the remainder lies on the conductive layer (40). For this reason, the part of the conductive bus bars that presses onto the transparent conductive layer (40) is visible from the outside when one looks at the laminated glass. In this way, the energy supplied to the (+) first terminal (1 ), which is connected to the power source (80), passes from the first bus bar (60) to the conductive layer (40), flows through the layer, and reaches the second terminal (2) at the second bus bar (70) on the opposite side before leaving the glass. During this flow, the glass heats up.

REFERENCE NUMBERS

1 First Terminal

2 Second Terminal

3 Upper Edge

4 Lower Edge

5 Buffer Region

10 Outer Panel

12 First Surface

14 Second Surface

20 Inner Panel

22 Third Surface

24 Fourth Surface

30 Interlayer

40 Conductive Layer

42 Bottom Surface

44 Top Surface

50 Opaque Layer

60 First Bus Bar

62 First Edge

64 Second Edge 66 Bottom Surface

68 Top Surface

70 Second Bus Bar

72 First Edge 74 Second Edge

76 Bottom Surface

78 Top Surface

80 Power Source

Claims

1. A laminated windshield comprising an outer panel (10), an inner panel (20) that together separate the vehicle interior from the external environment, and a thermoplastic interlayer (30) that bonds the outer panel (10) and the inner panel (20), characterized by a conductive layer (40) provided on a second surface (14) of the outer panel (20) facing the inner panel (10), a first terminal (1 ) and at least one second terminal (2) spaced apart in such a way as to complete a circuit with the conductive layer (40) and an opaque layer (50) provided on the conductive layer (40) so as to mask the first and second terminals (1 , 2) without preventing the electrical connection between them.

2. A windshield according to claim 1 , wherein comprising a first bus bar (60) and a second bus bar (70) that at least partially surround the opaque layer (50) and provide electrical conduction between the first and at least one second terminal (1 , 2) and the conductive layer (40).

3. A windshield according to claim 2, wherein the first and second bus bars (60, 70) contain silver.

4. A windshield according to any of claims 2-3, wherein the first and second bus bars (60,

70) have a patterned structure.

5. A windshield according to any of claims 2-4, wherein the first and second bus bars (60,

70) have a dotted patterned structure.

6. A windshield according to any of the preceding claims, wherein the first terminal (1 ) and the second terminal (2) are provided on opposite ends of the conductive layer (40) and that the first terminal (1 ) and the second terminal (2) are oppositely charged.

7. A windshield according to claim 6, wherein the first terminal (1) and the second terminal (2) are provided opposite each other on an upper edge (3) and a lower edge (4).

8. A windshield according to any of the preceding claims, wherein the conductive layer

(40) extends along the full length of the second surface (14).

9. A windshield according to any of the preceding claims, wherein the opaque layer (50) is an enamel black paint layer.

10. A windshield according to any of the preceding claims, wherein the outer panel (10) and the inner panel (20) have a curved structure.

11. A windshield according to any of the preceding claims, wherein the outer panel (10) and the inner panel (20) are laminated glass.

12. A windshield according to any of the preceding claims, wherein the outer panel (10) and the inner panel (20) have a thickness ranging from 0.3 to 2.7 mm.

13. A windshield according to any of the preceding claims, wherein direct current (DC) is supplied from a power source (80) to the first terminal (1 ) and at least one second terminal (2).

14. A windshield according to any of the preceding claims, wherein the thermoplastic interlayer (30) contains PVB.

15. A windshield according to any of the preceding claims, wherein a buffer region (5) is formed on the second surface (14) between the interlayer (30) and the external environment.