Laminated glass

Abstract

The present invention relates to a laminated glass comprising an inner plate glass, an outer plate glass, a reflective coating laminate disposed on the inner plate glass, and a film member disposed between the reflective coating laminate and the outer plate glass, the reflective coating laminate comprising: a metal layer reflecting p-polarization; a first dielectric layer disposed between the metal layer and the inner plate glass and including a first ceramic layer in which silicon nitride films and zinc tin oxide films are alternately laminated; and a second dielectric layer disposed between the metal layer and the film member and including a second ceramic layer in which silicon nitride films and zinc tin oxide films are alternately laminated, wherein the ratio of the optical thickness of the second dielectric layer to that of the first dielectric layer at a wavelength of 550 nm is 1.3 to 2.0.

Description

laminated glass

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0178504 filed on December 4, 2024, and all contents disclosed in said Korean application are incorporated herein as part of this specification.

[0002] The present invention relates to a laminated glass having high visible light transmittance and p-polarized reflectance, as well as excellent durability and heat resistance.

[0003]

[0004] Recently, the number of vehicles equipped with Head-Up Displays (HUDs) has been increasing. A HUD is a display system that projects information such as driving data, navigation, and fuel status into the driver's field of vision, allowing the driver to directly view necessary information without having to lower their head or move their gaze significantly. A HUD generally includes an image generation device that creates and projects the image to be displayed, and a reflective screen that reflects the generated image toward the driver. They can be classified into windshield types, where the vehicle's front windshield acts as the reflective screen, and combiner types, where a separate reflective screen is used to display the image on the screen. Since the screen size of the combiner type is limited, the demand for windshield-type HUDs is increasing. Conventional windshield-type HUD devices primarily operated by irradiating s-polarized light onto the vehicle's front windshield at an angle of incidence of approximately 60 degrees, close to the Brewster angle. This is intended to minimize reflection loss and increase transmission efficiency. However, since the car windshield is made of laminated glass in which two glass plates (inner glass plate and outer glass plate) are bonded together, when the car windshield is used as a reflective screen, there is a problem in that the reflective surface of the light generated from the image generating device becomes two, and a slightly misaligned secondary image, so-called ghost image, appears in addition to the desired primary image.

[0005] To solve these problems, a method has been proposed to control the light path within the laminated glass plate by placing a wedge-shaped film between the inner glass plate and the outer glass plate. Composite glasses having a wedge-shaped film for a HUD are known, for example, in WO2009 / 071135A1, EP1800855B1, or EP1880243A2.

[0006] However, wedge-shaped films are expensive, resulting in significant costs for producing composite glass for HUDs. Accordingly, a head-up display device has been proposed that uses p-polarized radiation, which is not significantly reflected by the surface of a glass plate, as a light source and forms a reflective layer that reflects p-polarized light on the inside or outside of the laminated glass. DE102014220189A1 introduces a HUD projection device that operates with p-polarized radiation and proposes a structure that forms a reflective layer composed of silver or aluminum. However, in the case of automotive windshields, the glass undergoes a bending process using heat during manufacturing, and there is a problem that the physical properties of the p-polarized reflective layer change or are damaged during this bending process. Additionally, since p-polarized light does not have a high reflectivity compared to s-polarized light, there is also a problem that it is difficult to achieve a clear image when using p-polarized light.

[0007] Therefore, there is a need to develop glass for head-up displays that does not damage the reflective layer within the glass even after undergoing a bending process, and simultaneously enables the realization of clear images even when using p-polarized light as a light source.

[0008]

[0009] One objective of the present invention is to provide a laminated glass that has excellent durability and heat resistance to prevent damage during the bending process, and has a high p-polarization reflectance to enable the realization of a clear image when applied to a head-up display system.

[0010]

[0011] According to one embodiment, the present invention provides a bonded glass comprising: an inner plate glass; an outer plate glass; a reflective coating laminate disposed on the inner plate glass; and a film member disposed between the reflective coating laminate and the outer plate glass, wherein the reflective coating laminate includes a metal layer that reflects p-polarized light, a first dielectric layer disposed between the metal layer and the inner plate glass and comprising a first ceramic layer in which a silicon nitride film and a zinc tin oxide film are alternately laminated, and a second dielectric layer disposed between the metal layer and the film member and comprising a second ceramic layer in which a silicon nitride film and a zinc tin oxide film are alternately laminated, and wherein the ratio of the optical thickness of the second dielectric layer to the first dielectric layer at a wavelength of 550 nm is 1.3 to 2.0.

[0012] The geometric thickness of the metal layer may be 7 nm to 22 nm.

[0013] The first dielectric layer may further include a first auxiliary dielectric layer disposed between the first ceramic layer and the metal layer.

[0014] The second dielectric layer may further include a metal protective layer and a second auxiliary dielectric layer between the metal layer and the second ceramic layer.

[0015] An overcoat layer may be further included between the second dielectric layer and the film member.

[0016] The above-mentioned bonded glass may have a p-polarized reflectance of 15% to 30% and a visible light transmittance of 67% to 90%.

[0017]

[0018] The laminated glass according to the present invention includes a ceramic layer in which a silicon nitride film and a zinc tin oxide film are alternately laminated in a reflective coating laminate, thereby increasing the heat resistance and flexibility of the reflective coating laminate and minimizing damage to the reflective coating laminate during the bending process of the laminated glass.

[0019] The laminated glass according to the present invention is designed to improve visible light transmittance and p-polarized reflectance by controlling the optical thickness of a first dielectric layer disposed below a metal layer and a second dielectric layer disposed above a metal layer. Accordingly, when the laminated glass of the present invention is used as a windshield for automobiles, the transparency of the windshield is maintained, thereby providing excellent visibility for the driver, while simultaneously enabling clear visualization of the head-up display image.

[0020] The laminated glass according to the present invention does not use expensive wedge-shaped films, so the manufacturing cost is relatively low.

[0021] When a bonded glass according to the present invention is combined with a p-polarizing projector and used as a head-up display system, the image is not blocked even when wearing polarized sunglasses, and a clear image is provided, thereby providing a comfortable driving environment for the driver.

[0022]

[0023] The present invention will be described in detail below.

[0024] In this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0025] Additionally, in this specification, when it is stated that a component is located "on" another component, this includes not only cases where a component is in contact with another component, but also cases where another component exists between the two components.

[0026]

[0027] laminated glass

[0028] The laminated glass according to the present invention comprises a reflective coating laminate, a film member, and an outer plate glass sequentially laminated on an inner plate glass.

[0029] The above-described reflective coating laminate comprises: a metal layer that reflects p-polarized light; a first dielectric layer disposed below the metal layer and comprising a first ceramic layer in which a silicon nitride film and a zinc tin oxide film are alternately stacked; and a second dielectric layer disposed above the metal layer and comprising a second ceramic layer in which a silicon nitride film and a zinc tin oxide film are alternately stacked.

[0030] At this time, the ratio of the optical thickness of the second dielectric layer to the first dielectric layer at a wavelength of 550 nm may be 1.3 to 2.0, preferably 1.4 to 1.9, and more preferably 1.5 to 1.8. If the ratio of the optical thickness of the second dielectric layer to the first dielectric layer is less than 1.3, a problem may occur in which the visible light transmittance is lowered or the p-polarized reflectance is lowered, and if it exceeds 2.0, a problem may occur in which the visible light transmittance is lowered or the p-polarized reflectance is lowered.

[0031]

[0032] Hereinafter, each component of the laminated glass according to the present invention will be described in more detail.

[0033]

[0034] <Inner Plate Glass and Outer Plate Glass>

[0035] The laminated glass according to the present invention includes an inner plate glass and an outer plate glass.

[0036] The inner glass plate and the outer glass plate are arranged in a structure facing each other, and the inner glass plate includes an outer surface facing the interior and an inner surface facing the outer glass plate. The outer glass plate includes an outer surface facing the exterior and an inner surface facing the inner glass plate.

[0037] A reflective coating laminate and a film member are sequentially laminated between the inner glass plate and the outer glass plate.

[0038] The inner plate glass and the outer plate glass may be composed of conventional glass materials used for construction or automobiles, and may be formed by including, for example, materials such as float glass, quartz glass, borosilicate glass, soda-lime glass, polyethylene, polypropylene, polycarbonate, and polymethyl methacrylate.

[0039] The inner plate glass and the outer plate glass may use glass of an appropriate thickness depending on the purpose of use. For example, the geometric thickness of the inner plate glass may be 1.0 mm to 3.2 mm, specifically 1.4 mm to 2.4 mm, more specifically 1.5 mm to 2.3 mm. The geometric thickness of the outer plate glass may be 1.0 mm to 3.2 mm, specifically 1.4 mm to 2.4 mm, more specifically 1.5 mm to 2.3 mm. If the above range is satisfied, the problem of damage to the manufactured laminated glass during the bending process can be prevented, and the optical characteristics intended to be realized by the laminated glass of the present invention can be achieved.

[0040]

[0041] Reflective Coating Laminate

[0042] The laminated glass according to the present invention includes a reflective coating laminate disposed between the inner plate glass and the film member. The reflective coating laminate is intended to reflect p-polarized light generated from a projector of a head-up display toward the driver, and may be formed by sequentially coating a first dielectric layer, a metal layer, and a second dielectric layer on the inner surface of the inner plate glass.

[0043] The geometric thickness of the reflective coating laminate according to the present invention may be 70 nm to 230 nm, specifically 100 nm to 200 nm, more specifically 110 nm to 170 nm. When satisfying the above range, the laminated glass according to the present invention may exhibit more optimized optical properties and mechanical properties.

[0044] The optical thickness of the reflective coating laminate according to the present invention may be 200 nm to 350 nm, specifically 210 nm to 340 nm, more specifically 220 nm to 330 nm, and even more specifically 230 nm to 320 nm. When the optical thickness of the reflective coating laminate satisfies the above range, the visible light transmittance and p-polarized reflectance intended to be realized by the bonded glass of the present invention can be achieved. At this time, the optical thickness is defined as the value obtained by multiplying the geometric thickness and the refractive index, and in the present invention, "refractive index" and "geometric thickness" are the refractive index value and the geometric thickness value measured for a wavelength of 550 nm using a spectroscopic ellipsometer.

[0045] The optical thickness of the reflective coating laminate affects the reflectance of p-polarized light, the transmittance of visible light, and interference phenomena generated by the projector of a head-up display system. Specifically, by adjusting the optical thickness, it is possible to design the laminate so that light of a specific wavelength is reflected or transmitted more. The optical thickness of the reflective coating laminate can be adjusted by controlling the geometric thickness and refractive index of the first dielectric layer, the geometric thickness and refractive index of the second dielectric layer, and the ratio of the optical thickness of the second dielectric layer to the first dielectric layer, which will be described later.

[0046] Hereinafter, each layer of the reflective coating laminate according to the present invention will be described in more detail.

[0047] (1) Metal layer

[0048] The above metal layer is intended to reflect p-polarized light generated from the projector of the head-up display so that the display image is formed in the direction of the driver's field of vision.

[0049] Specifically, the metal layer may comprise silver (Ag), gold (Au), copper (Cu) elements, or an alloy in which at least one element selected from the group consisting of nickel (Ni), lead (Pd), titanium (Ti), platinum (Pt), and chromium (Cr) is doped into the said elements. When the metal layer is composed of silver (Ag), it is preferable in that the p-polarized reflectance and visible light transmittance in the reflective coating laminate can be further improved.

[0050] The number of metal layers and geometric thickness of the above metal layers affect the optical properties and mechanical properties of the laminated glass formed at the end. Specifically, silver (Ag), which is the metal mainly used for the metal layers, is a metal with a relatively high reflectivity compared to other metals, and if the number of metal layers increases or the geometric thickness becomes excessively thick, the visible light transmittance of the laminated glass formed at the end may decrease and its durability may be reduced.

[0051] Although the number of metal layers is not particularly limited, it is preferable to have one metal layer in order to prevent problems that may occur when the number increases as described above.

[0052] The above metal layer may have a geometric thickness of 7 nm to 22 nm, specifically 8 nm to 20 nm, more specifically 9 nm to 18 nm, and even more specifically 10 nm to 16 nm. When the above range is satisfied, the visible light transmittance and p-polarized reflectance of the laminated glass can have values ​​suitable for realizing the effects of the present invention, while at the same time preventing damage to the laminated glass after the bending process.

[0053]

[0054] (2) First dielectric layer and second dielectric layer

[0055] The reflective coating laminate according to the present invention includes dielectric layers on the upper and lower portions of the metal layer. Specifically, the reflective coating laminate according to the present invention includes a first dielectric layer disposed between the metal layer and the inner glass plate, and a second dielectric layer disposed between the metal layer and a film member to be described later.

[0056] The first dielectric layer and the second dielectric layer improve the durability and heat resistance of the reflective coating laminate to prevent damage after the bending process and perform the function of improving visible light and p-polarized light reflectance.

[0057] The first dielectric layer comprises a first ceramic layer in which a silicon nitride film and a zinc tin oxide film are alternately stacked, and may further comprise a first auxiliary dielectric layer as needed.

[0058] The second dielectric layer comprises a second ceramic layer in which a silicon nitride film and a zinc tin oxide film are alternately stacked, and may further include a metal protective layer and a second auxiliary dielectric layer as needed.

[0059] Each layer constituting the first dielectric layer and the second dielectric layer will be described later.

[0060] The ratio of the optical thickness of the second dielectric layer to the first dielectric layer at a wavelength of 550 nm may be 1.3 to 2.0, preferably 1.4 to 1.9, and more preferably 1.5 to 1.8. If the ratio of the optical thickness of the second dielectric layer to the first dielectric layer is less than 1.3, a problem may occur in which the visible light transmittance is lowered or the p-polarized reflectance is lowered, and if it exceeds 2.0, a problem may occur in which the visible light transmittance is lowered or the p-polarized reflectance is lowered.

[0061] The geometric thickness of the first dielectric layer may be 20 nm to 100 nm, specifically 25 nm to 80 nm, more specifically 30 nm to 60 nm, and the geometric thickness of the second dielectric layer may be 40 nm to 100 nm, specifically 50 nm to 90 nm, more specifically 60 nm to 80 nm. If the above ranges are satisfied, the optical properties of the bonded glass of the present invention can be realized, and damage during the bending process can be prevented.

[0062] The optical thickness of the first dielectric layer according to the present invention may be 40 nm to 200 nm, specifically 50 nm to 160 nm, more specifically 60 nm to 120 nm, and even more specifically 70 nm to 100 nm.

[0063] In addition, the optical thickness of the second dielectric layer according to the present invention may be 60 nm to 240 nm, specifically 80 nm to 200 nm, more specifically 100 nm to 180 nm, and more specifically 120 nm to 160 nm.

[0064] When the optical thicknesses of the first dielectric layer and the second dielectric layer each independently satisfy the above range, the p-polarization reflectance and visible light transmittance of the bonded glass can be improved to the extent that the present invention aims to achieve.

[0065]

[0066] (First ceramic layer and second ceramic layer)

[0067] The first dielectric layer and the second dielectric layer of the present invention are each independently silicon nitride films (SiN x ) and zinc tin oxide film (ZnSnO y It includes a first ceramic layer and a second ceramic layer that are alternately stacked.

[0068] The first ceramic layer and the second ceramic layer are deposited alternately with ceramic layers of different materials to prevent defects from occurring in the coating film after heat treatment and bending, and by controlling the geometric thickness and optical thickness of the first ceramic layer and the second ceramic layer, a specific range of visible light transmittance, p-polarized reflectance, and desired color can be realized.

[0069] Specifically, a conventional ceramic layer is a silicon-containing nitride, more specifically SiAlN a or Si b N c (a may include 1 to 1.5, b 2 to 4, and c 3 to 5). Silicon-containing nitrides have been primarily used due to their optical properties, easy solubility, and high mechanical and chemical stability. However, problems may arise when a dielectric layer with an appropriate optical thickness is manufactured using silicon-containing nitrides with these properties and then subjected to a bending process of laminated glass. For example, laminated glass using a dielectric layer comprising a ceramic layer made solely of silicon-containing nitrides may break or be damaged during the bending process.

[0070] More specifically, silicon-containing nitrides are characterized by a low coefficient of thermal expansion. The coefficient of thermal expansion is a value indicating how much a material expands or contracts with changes in temperature, typically expressed in ppm / °C. A low coefficient of thermal expansion means that there is almost no mechanical deformation due to temperature changes. Unlike cases where a low coefficient of thermal expansion is required, such as in cutting tools or engine parts, the low coefficient of thermal expansion of silicon-containing nitrides may not be suitable in applications where the shape of the laminated glass needs to be deformed for purposes such as adjusting curvature during the bending process or for other purposes, such as in laminated glass used in head-up display systems.

[0071] To solve these problems, the present invention provides a first ceramic layer and a second ceramic layer, each independently having a silicon nitride film (SiN x ) and zinc tin oxide film (ZnSnO y A structure in which the layers are alternately stacked is used. A laminated glass in which the ceramic layer is composed of a structure in which a silicon nitride film and a zinc tin oxide film are alternately stacked, as in the present invention, has different physical properties from a laminated glass in which the ceramic layer is composed of only one material, namely silicon nitride or zinc tin oxide.

[0072] Specifically, although zinc tin oxide has relatively lower mechanical strength compared to silicon nitride, unlike silicon nitride, which has an average thermal expansion coefficient of 2.5 to 3.2 ppm / ℃, zinc tin oxide has an average thermal expansion coefficient of 6 to 10 ppm / ℃, thus possessing moderate thermal resistance. Therefore, when a ceramic layer is manufactured by alternating it with silicon nitride, the ceramic layer can secure mechanical strength and processability in the bending process, thereby solving the aforementioned problems that may occur when the ceramic layer is composed of silicon nitride alone.

[0073] The zinc tin oxide film has transparency similar to that of a silicon nitride film, so it can play a role in helping the bonded glass according to the present invention achieve the visible light transmittance it aims to realize.

[0074] The number of silicon nitride films and zinc tin oxide films included in the first ceramic layer and the second ceramic layer is not particularly limited and can be adjusted to achieve optical properties such as visible light transmittance and p-polarized reflectance, as well as durability and heat resistance of the bonded glass, which are intended to be realized by the present invention. Specifically, when a silicon nitride film and a zinc tin oxide film are each stacked as one layer, the first ceramic layer may include one or two sets, and the second ceramic layer may include two to five sets, two to four sets, or two and three sets. When the above range is satisfied, the condition for the optical thickness ratio of the second dielectric layer to the first dielectric layer according to the present invention can be satisfied, and the optical properties and mechanical properties intended to be realized can be achieved.

[0075] The material of the silicon nitride film included in the first ceramic layer and the second ceramic layer is specifically SiN x (x can be 0.5 to 1.5), and the material of the zinc tin oxide film is ZnSnO y (y can be 0.5 to 2), and the stacking method of the silicon nitride film and the zinc tin oxide film is not particularly limited as long as it is a method that can be deposited in the form of a thin film. For example, it can be deposited by CVD, PECVD, or magnetron sputtering.

[0076] The ceramic layer may include one or more selected from the group consisting of metal nitrides, metal oxides, and metal nitrides, and the metals of the conventional ceramic layer may include zinc (Zn), titanium (Ti), silicon (Si), niobium (Nb), tin (Sn), aluminum (Al), zirconium (Zr), tantalum (Ta), or alloys thereof. Specifically, it is preferable that the ceramic layer include metal nitrides and metal oxides in order to effectively prevent defects during the bending process after heat treatment of bonded glass.

[0077]

[0078] The optical thickness of the first ceramic layer may be 20 nm to 200 nm, specifically 30 nm to 180 nm, more specifically 40 nm to 160 nm, more specifically 50 nm to 140 nm, and more specifically 60 nm to 120 nm, and the optical thickness of the second ceramic layer may be 60 nm to 240 nm, specifically 80 nm to 200 nm, more specifically 100 nm to 180 nm, more specifically 120 nm to 170 nm, and more specifically 130 nm to 160 nm. When the above ranges are satisfied, the visible light transmittance and p-polarized reflectance intended to be achieved by the bonded glass of the present invention can be achieved.

[0079] The geometric thickness of the first ceramic layer may be 15 nm to 100 nm, specifically 25 nm to 80 nm, more specifically 30 nm to 60 nm, and even more specifically 35 nm to 55 nm. The geometric thickness of the second ceramic layer may be 30 nm to 120 nm, specifically 40 nm to 100 nm, more specifically 50 nm to 90 nm, and even more specifically 60 nm to 80 nm. When the above ranges are satisfied, the bonded glass of the present invention can secure mechanical properties that are not damaged even after undergoing a bending process.

[0080] (1st auxiliary dielectric layer and 2nd auxiliary dielectric layer)

[0081] The first dielectric layer may further include a first auxiliary dielectric layer disposed between the first ceramic layer and the metal layer. Additionally, the second dielectric layer may further include a second auxiliary dielectric layer disposed between the second ceramic layer and the metal layer.

[0082] The first auxiliary dielectric layer and the second auxiliary dielectric layer play a role in helping to achieve the p-polarized reflectance intended for the bonded glass by improving the crystallinity of the metal layer.

[0083] The first auxiliary dielectric layer and the second auxiliary dielectric layer may each independently include a metal nitride, a metal oxide, or a metal nitride, and may include, for example, zinc (Zn), titanium (Ti), silicon (Si), niobium (Nb), tin (Sn), aluminum (Al), zirconium (Zr), tantalum (Ta), or an alloy thereof.

[0084] Specifically, the first auxiliary dielectric layer and the second auxiliary dielectric layer may each independently comprise a zinc-containing oxide, and the zinc-containing oxide is ZnAlO n Examples include, and n can be 0.1 to 3 or 0.5 to 2.

[0085] The optical thickness of the first auxiliary dielectric layer and the second auxiliary dielectric layer may each be independently 1 nm to 20 nm, specifically 3 nm to 16 nm, more specifically 6 nm to 12 nm. If the above range is satisfied, the optical thickness ratio of the second dielectric layer to the first dielectric layer can be satisfied.

[0086] The geometric thickness of the first auxiliary dielectric layer and the second auxiliary dielectric layer may each be independently 1 nm to 10 nm, specifically 2 nm to 8 nm, more specifically 3 nm to 6 nm. When the above range is satisfied, the problem of reduced durability and heat resistance of the manufactured bonded glass can be prevented, and the p-polarized reflectance can be improved.

[0087] (Metal protective layer)

[0088] The reflective coating laminate according to the present invention may further include a metal protective layer disposed between the metal layer and the second auxiliary dielectric layer.

[0089] The metal protective layer prevents oxidation of the metal layer, prevents damage to the metal layer due to heat treatment and physical friction during the manufacturing process of the laminated glass, and improves the adhesion between the metal layer and the second dielectric layer. In addition, the metal protective layer helps to fuse the metal within the metal layer so that the metal layer can behave stably even at high heat treatment temperatures, and absorbs oxygen (O2) penetrating the metal layer to help realize the optical properties of the laminated glass.

[0090] The metal protective layer may include one or more selected from the group consisting of nickel (Ni), chromium (Cr), and nickel (Ni)-chromium (Cr) alloys, specifically nickel (Ni)-chromium (Cr) alloy. When the metal protective layer includes a nickel (Ni)-chromium (Cr) alloy, it has low reactivity to active gases and can effectively block active gases. On the other hand, when the metal protective layer includes metals and / or alloys other than those described above, a blurring phenomenon may occur, which is a phenomenon in which visual clarity is reduced due to problems such as oxygen diffusion after heat treatment.

[0091] The optical thickness of the metal protective layer may be 0.2 nm to 2 nm, specifically 0.4 nm to 1.6 nm, more specifically 0.6 nm to 1.2 nm. Additionally, the geometric thickness of the metal protective layer may be 0.1 nm to 1.0 nm, specifically 0.2 nm to 0.8 nm, more specifically 0.3 nm to 0.6 nm. If the above ranges are satisfied, problems such as reduced durability of the laminated glass and increased blurring of the coating film after heat treatment and bending processes can be prevented.

[0092]

[0093] The reflective coating laminate according to the present invention may have a structure in which a first ceramic layer, a first auxiliary dielectric layer, a metal layer, a metal protective layer, a second auxiliary dielectric layer, and a second ceramic layer are stacked in that order.

[0094] Specifically, the reflective coating laminate according to the present invention is SiN x -ZnSnO y -ZnAlO-Ag-NiCr-ZnAlO-ZnSnO y -SiN x -ZnSnO y -SiN x -ZnSnO y -SiN x -ZnSnO y It may be a structure in which the layers are stacked in sequence. When the reflective coating laminate has the above structure, the durability and heat resistance of the laminated glass using the reflective coating laminate are further improved, thereby preventing the problem of damage occurring even after the bending process, and the visible light transmittance and P-polarized reflectance intended to be realized by the present invention can be achieved.

[0095]

[0096] Overcoat layer

[0097] The bonded glass according to the present invention may further include, if necessary, an overcoat layer disposed between the second dielectric layer and the film member.

[0098] The above overcoat layer complements the physical and chemical durability of the second dielectric layer and serves to protect against physical and chemical damage from the external environment.

[0099] The above overcoat layer may be applied in one or more layers and may include a material having high mechanical strength, low surface roughness, and high visible light transmittance. For example, the above overcoat layer may include a metal oxide, a metal nitride, or a metal nitride.

[0100] For example, the metals that may be included in the overcoat layer may include silicon (Si), niobium (Nb), titanium (Ti), zirconium (Zr), tantalum (Ta), aluminum (Al), alloys thereof, or oxides, nitrides, or nitride oxides thereof. Specifically, the overcoat layer may include silicon, zirconium, titanium, or oxides thereof, more specifically titanium oxide (TiO2).

[0101] In addition, the geometric thickness of the overcoat layer may be 0.3 nm to 3.5 nm, specifically 0.4 nm to 3 nm, and more specifically 0.5 nm to 2.5 nm. If the above range is satisfied, problems such as reduced durability and heat resistance of the manufactured laminated glass can be prevented. If the geometric thickness of the overcoat layer is less than the above range, the mechanical and chemical durability of the coating layer and the handling properties of the laminated glass may be reduced, and if it exceeds the above range, problems such as increased deposition time of the thin film and reduced productivity may occur.

[0102]

[0103] Film Absence

[0104] The laminated glass according to the present invention includes a film member disposed between the reflective coating laminate and the outer plate glass.

[0105] The above film member enhances structural stability by strengthening the bonding of thin films, ensures user safety by preventing the spread of fragments in the event of glass breakage, and functions to block ultraviolet rays from the outside.

[0106] The above film member may be of various types depending on the application. Specifically, it may include one or more selected from the group consisting of polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), and polyurethane (TPU).

[0107] The film member may have a geometric thickness of 0.2 mm to 2.0 mm, specifically 0.4 mm to 1.0 mm, more specifically 0.5 mm to 0.9 mm. If the average thickness of the film member is less than the above range, the complexity of the process increases due to the thin thickness during the bonding process, and problems may arise where the bonded glass is damaged due to vulnerability to external impact after bonding. If the geometric thickness of the film member exceeds the above range, the hardness of the bonded glass becomes excessively high, which may reduce production efficiency by requiring an additional process to apply additional force during the bending process, and the weight of the bonded glass increases, which may cause problems in increasing the fuel efficiency of the vehicle to which the bonded glass is applied.

[0108]

[0109] Meanwhile, the p-polarization reflectance of laminated glass used in head-up display systems must be above a certain level because it affects visual quality and energy efficiency aspects, such as screen visibility, system efficiency, and the contrast and color accuracy of the information displayed on the screen. However, if the p-polarization reflectance is too high, the quality of the projected image or information may deteriorate, and the user's field of vision may be obstructed.

[0110] Reflectance refers to the ratio of the amount of light reflected to the amount of light incident. Reflectance is expressed as a % (based on 100% incident radiation). It is expressed as a function of wavelength to form a reflection spectrum. In the context of the present invention, the description of the reflectance of p-polarized light is based on the reflectance measured at an angle of incidence of 65° with respect to the internal surface normal. Data regarding the reflectance or reflection spectrum is based on reflection measurements using a light source that emits uniformly with a normalized radiance of 100% over the spectral range under consideration.

[0111] In a spectral range of 380 nm to 780 nm, the laminated glass according to the present invention may have a p-polarized reflectance of 15% or more and 30% or less, specifically 16% or more and 27% or less, more specifically 17% or more and 24% or less, and more specifically 18% or more and 22% or less. When the user satisfies the above range for the p-polarized reflectance of the laminated glass, the screen of the head-up display using the laminated glass becomes clearer, and the visual quality of the display is improved.

[0112] Meanwhile, in the present invention, a spectral range of 380 nm to 780 nm was used, because the optical impression is mainly formed by this spectral range. In addition, the spectral range includes relevant wavelengths (RGB, 478 nm, 550 nm, 630 nm) for head-up displays.

[0113] In addition, the high visible light transmittance of laminated glass offers advantages in terms of visual clarity and comfort. Visible light transmittance is an indicator of how well visible light, with wavelengths ranging from approximately 380 nm to 780 nm that humans can see, is transmitted through glass. High visible light transmittance of laminated glass improves visual clarity by allowing the external environment to be seen more clearly, and in particular, high visible light transmittance of laminated glass used in head-up display systems enhances visibility and safety by allowing the user to see the external environment more clearly.

[0114] The laminated glass according to the present invention may have a visible light transmittance of 67% to 90%, preferably 67% to 85%, and more preferably 70% to 80%. When the above range is satisfied, it is desirable in that a head-up display system using the laminated glass according to the present invention can realize a display with higher clarity and comfort.

[0115] Meanwhile, the bonded glass according to the present invention can be manufactured using a vacuum sputtering method as a thin film forming method for forming each layer. That is, the method for manufacturing the bonded glass according to the present invention may include the step of forming each layer by a sputtering deposition method.

[0116]

[0117] The bonded glass according to the present invention can be combined with a projector that generates p-polarization and can be usefully used as a head-up display system.

[0118] When a projector that generates p-polarization and a laminated glass containing a reflective coating laminate according to the present invention are used together, ghosting is minimized and a clear image can be realized.

[0119] The projector generating the above p-polarization may generate pure p-polarization alone, or it may generate p-polarization along with other polarizations. Unlike s-polarization, p-polarization has the characteristic that it can be transmitted almost completely at a specific angle (Brewster angle) when light is incident on the boundary surface of a material. Therefore, when the projector of a head-up display system generates p-polarization, unnecessary reflections on reflective surfaces can be minimized, thereby preventing the occurrence of double images (ghost images). In addition, since conventional polarized sunglasses block s-polarization and allow p-polarization to pass through, there is an advantage that users wearing polarized sunglasses can also see the screen clearly.

[0120] However, as described above, p-polarization minimizes unnecessary reflection, so it has the characteristic of having a lower degree of reflection compared to s-polarization. Therefore, in a head-up display system using a projector that generates p-polarization, a laminated glass having a sufficient degree of p-polarization reflectance must be used so that the user can see a clear image. Since the laminated glass according to the present invention has a high p-polarization reflectance of 20% or more as described above, when the laminated glass according to the present invention is used together with a projector that generates p-polarization, the clarity of the head-up display screen can be secured.

[0121]

[0122] The present invention will be explained in more detail below through examples. However, these examples are intended only to aid in understanding the invention and do not limit the scope of the invention in any way.

[0123] [Examples and Comparative Examples]

[0124] Example 1.

[0125] Soda-lime glass is used as the inner glass plate, and SiN is applied to one surface of the inner glass plate using a sputtering device. x / ZnSnO y / ZnAlO / Ag / NiCr / ZnAlO / ZnSnO y / SiN x / ZnSnO y / SiN x / ZnSnO y / SiN x / ZnSnO y / TiO2 layers were sequentially deposited. At this time, the thickness of each layer is as shown in Table 1 below.

[0126] After the film formation is completed, two glass plates are formed at a high temperature using soda-lime glass as the outer glass plate and then bonded. Specifically, after heat treatment is performed at 640°C for 15 minutes, a 0.76 mm colorless PVB film is used to bond the inner and outer glass plates that have finished forming.

[0127]

[0128] Example 2 and Comparative Examples 1 to 3

[0129] A laminated glass was manufactured in the same manner as in Example 1, except that the thickness and composition of each layer were adjusted as described in Tables 1 and 2.

[0130] Classification Refractive Index Example 1 Example 2 Comparative Example 1 (550 nm) Geometric Thickness (nm) Optical Thickness (nm) Geometric Thickness (nm) Optical Thickness (nm) Geometric Thickness (nm) Optical Thickness (nm) Outer Glass Plate Geometric Thickness 2.1 mm PVB Film Geometric Thickness 0.76 mm Overcoat Layer TiO2 2.3 1.7 3.9 1 1.7 3.9 1 1.7 3.9 1 Second Ceramic Layer ZnSnO y 210.621.20010.621.2SiN x 28.617.2001836ZnSnO y 210.621.210.621.210.621.2SiN x 28.617.219.238.41836ZnSnO y 210.621.210.621.210.621.2SiN x 28.617.219.238.41836ZnSnO y 210.621.210.621.210.621.2 Second auxiliary dielectric layer ZnAlO25 105 105 10 Metal protective layer NiCr2.5 0.4 10.4 10.41 Metal layer Ag 0.1 11.8 1.18 11.8 1.18 11.8 1.18 First auxiliary dielectric layer ZnAlO25 105 105 10 First ceramic layer ZnSnO y 210.621.210.621.210.621.2SiN x2306030603060 Internal glass plate geometric thickness 2.1mm Second dielectric layer-73.6147.475.6151.4101.8203.8 First dielectric layer-45.691.245.691.245.691.2 Optical thickness ratio of the second dielectric layer to the first dielectric layer--1.62-1.66-2.23

[0131] Classification Refractive Index (550 nm) Comparative Example 2 Comparative Example 3 Geometric Thickness (nm) Optical Thickness (nm) Geometric Thickness (nm) Optical Thickness (nm) Outer Glass Plate Geometric Thickness 2.1 mm PVB Film Geometric Thickness 0.76 mm Overcoat Layer TiO2 2.3 1.7 3.9 1 1.7 3.9 1 Second Ceramic Layer ZnSnO y 2----SiN x 2----ZnSnO y 2----SiN x 2----ZnSnO y 2--72.6145.2SiN x 271.2142.4--ZnSnO y 2----2nd auxiliary dielectric layer ZnAlO25 105 10 Metal protective layer NiCr2.5 0.4 10.4 1 Metal layer Ag 0.1 1 1.8 1.18 11.8 1.18 1st auxiliary dielectric layer ZnAlO25 105 10 1st ceramic layer ZnSnO y 2----SiN x 251.8103.638.577 Inner plate glass geometric thickness 2.1 mm Second dielectric layer - 76.6153.478156.2 First dielectric layer - 56.8113.643.587 Optical thickness ratio of the second dielectric layer to the first dielectric layer - 1.35 - 1.80

[0132] Experimental Example 1: Evaluation of Glass Properties

[0133] The visible light transmittance, p-polarized reflectance, and damage after bending of the laminated glass prepared in Examples 1 and 2 and Comparative Examples 1 to 3 were measured in the following manner. The measurement results are shown in [Table 3] below.

[0134] (1) Visible light transmittance

[0135] KS L 0066 was used as the evaluation standard, and measurements were performed using a Spectrophotometer. After coating a metal thin film on a glass plate, the visible light transmittance of the laminated glass prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was measured.

[0136] (2) p-polarized reflectance

[0137] KSL 2514 was used as the evaluation standard, and measurements were performed using a Spectrophotometer. After coating a metal thin film on a glass plate, the p-polarized reflectance of the bonded glass prepared in Examples 1 and 2 and Comparative Examples 1 to 3 was measured.

[0138] (3) Whether there is damage after bending

[0139] The laminated glass according to Examples 1 and 2 and Comparative Examples 1 to 3 was heat-treated at 640°C and then subjected to a bending process until a desired degree of bending was achieved. At this time, it was checked whether there were any defects, such as breakage or cracks, that could be visually observed from a distance of 75 cm.

[0140] Visible light transmittance p-polarized reflectance Damage after bending Example 170.8 20.1 Good Example 270.2 20.4 Good Comparative Example 165.4 22.3 Good Comparative Example 270.5 20.2 Occurrence of defect Comparative Example 370.1 20.8 Occurrence of defect

[0141] Referring to Table 3 above, depending on the optical thickness ratio of the second dielectric layer to the first dielectric layer and whether silicon nitride film and zinc tin oxide film are alternately stacked within the first ceramic layer and the second ceramic layer, the degree of visible light transmittance and p-polarized reflectance and the presence of defects after the bending process of the bonded glass may differ.

[0142] Specifically, Examples 1 and 2 satisfy the optical thickness ratio and have a structure in which a silicon nitride film and a zinc tin oxide film are alternately stacked within the first ceramic layer and the second ceramic layer, whereas Comparative Examples 1 to 3 do not satisfy one or more of the above configurations.

[0143] Comparative Example 1, which shows a visible light transmittance of less than 70%, has an optical thickness ratio of the second dielectric layer to the first dielectric layer of 2.23, which exceeds the upper limit of the optical thickness ratio according to the present invention, which is 2.0; Comparative Example 2, in which a defect occurs when the bonded glass undergoes a bending process, has the first ceramic layer and the second ceramic layer composed only of silicon nitride films; and Comparative Example 3, in which a defect occurs during bending in the same way as Comparative Example 2, has the first ceramic layer composed only of silicon nitride films and the second ceramic layer composed only of zinc tin oxide films.

[0144] This means that in order to achieve visible light transmittance and p-polarized reflectance above a certain level and prevent damage to the bonded glass even if it undergoes a bending process, the optical thickness ratio of the second dielectric layer to the first dielectric layer must satisfy a certain level, and the first ceramic layer and the second ceramic layer must have a structure in which silicon nitride film and zinc tin oxide film are alternately stacked.

Claims

1. Includes an inner plate glass, an outer plate glass, a reflective coating laminate disposed on the inner plate glass, and a film member disposed between the reflective coating laminate and the outer plate glass, The above-described reflective coating laminate comprises: a metal layer that reflects p-polarized light; a first dielectric layer disposed between the metal layer and the inner glass plate, comprising a first ceramic layer in which a silicon nitride film and a zinc tin oxide film are alternately stacked; and a second dielectric layer disposed between the metal layer and the film member, comprising a second ceramic layer in which a silicon nitride film and a zinc tin oxide film are alternately stacked. Bonded glass having a ratio of the optical thickness of the second dielectric layer at a wavelength of 550 nm to the first dielectric layer of 1.3 to 2.

0.

2. In Claim 1, Bonded glass having a geometric thickness of the metal layer of 7 nm to 22 nm.

3. In Claim 1, A bonded glass, wherein the first dielectric layer further comprises a first auxiliary dielectric layer disposed between the first ceramic layer and the metal layer.

4. In Claim 1, The second dielectric layer further includes a metal protective layer and a second auxiliary dielectric layer between the metal layer and the second ceramic layer, A bonded glass in which the metal protective layer is disposed between the metal layer and the second auxiliary dielectric layer.

5. In Claim 1, Bonded glass further comprising an overcoat layer between the second dielectric layer and the film member.

6. In Claim 1, The above laminated glass has a p-polarization reflectance of 15% to 30% and a visible light transmittance of 67% to 90%.