Technical Field

The present disclosure relates, in general to a solar protective vehicle glazing, and more specifically to a solar protective vehicle glazing with enhanced durability & improved passenger experience with aesthetically pleasant reflectance color.

Background

Solar control glazings have a large part to play in preventing the transmission of solar heat into buildings and passenger compartments of a vehicle. Especially in vehicles, such as cars, buses, railway carriages and also in aircrafts that have a number of window openings in their bodywork, into which these solar control glazings are fitted. These window openings include windscreens, rear window glazings, side window glazings and roof glazings. The primary objective of these different glazings in the vehicle bodywork is to protect the vehicle occupants from solar radiation and thereby limit the solar heat gain of the vehicle. This is of significant relevance in instances where the vehicle is parked in an unshaded location and also for vehicles in countries with hot-humid climates.

Widely available glazing panels in addition to limiting solar heat gain, filter a high portion of visible radiation in order to cut down the glare within the vehicle. But such glazing panels are not suitable for vehicles, as vehicle windscreen, side and rear windows require a high visible light transmission. It is a legal requirement in some countries that the visible light transmissivity of a road vehicle windscreen should be at least 70% and that of a rear and side window be at least 50%. Therefore, limiting the solar heat gain should be obtained while also maintaining appropriate visible light transmission.

Further, vehicle glazings should also contribute to temperature regulation conditions in winter by avoiding heat lost outside the passenger compartments of a vehicle. Thus the glazings must have low-emission properties that counter the emission of energy radiation from the passenger compartments of a vehicle. Furthermore, glazing should be capable of withstanding heat treatments without their reflectance color being substantially modified.

A wide variety of coating materials have been proposed for vehicle glazing panels for obtaining several desired properties outlined above. French patent application number 2676074 assigned to the assignee of the present disclosure discloses a solar protection glazing comprising a functional layer based on nickel, chromium and nitride deposited on a layer of titanium oxide. Further the functional layer is covered with a layer made of tantalum oxide or titanium oxide or titanium nitride. Said glazing finds application in building and automobile. Canadian application number 2178033 discloses a pyrolytically formed glazing panel for solar screening properties for use in vehicle glazing such as sunroof. The glazing panel comprises tin/antimony oxide coating layer and has a solar factor of less than 70%. Similarly, U.S. patent number 4,968,563 discloses a light transmitting glazing pane comprising a first coating of tin oxide provided on one of the glass faces and a second coating of titanium dioxide on the other face of the glass. Said glazing pane has a light transmission of at least 70% and a solar energy radiant transmissivity of 75%. Yet another U.S. patent number 9,561,981 discloses a motor vehicle glass panel comprising a multilayer stack including a metal alloy layer of chromium and zirconium placed in between a first dielectric and a second dielectric layer.

Notwithstanding all the coating materials that are available in the prior art for providing a solar protective glazing for automobiles, also popularly known are conventional solar protective films and tinted glazing panels that cut down the UV rays of the sun. However, the problem associated with the usage of such tinted glazing panels and protective films is the unpleasant experience of the vehicle passengers. This is because of the heavily tinted glazing and solar protective films giving a dark green/ dark grey color appearance inside of the vehicle, which are largely unappealing to the passengers.

Therefore, there is a constant need in the market for having a solar protective vehicle glazing which in addition to having all the desirable performance properties, have also appealing aesthetic properties. Likewise, it is further significant for these solar control glazings used in automobile applications to have improved durability in terms of abrasion resistance and scratch resistance owing to: (i) the process of bending associated with the manufacture of these glazing, during which the glazing panels come in contact with the BT rollers [the coating side of the glazing panels is exposed to the rollers] and (ii) usage of such glazings for side windows of a vehicle which exposes the coating to constant abrasion against the sealing lip of the vehicle window.

Hence the invention provided in the present disclosure addresses specific problem statements of existing prior art covering automotive glazing panels such as: (i) insufficient durability and (ii) unpleasant aesthetic properties, without compromising on the performance properties of the glazing panels such as light transmittance, solar factor and emissivity.

The present disclosure relates to a solar protective vehicle glazing that comprises at least one coated glass pane, which in turn comprises a multilayer stack on the face of the glass which faces the internal compartments of a vehicle. The multilayer stack comprises a first dielectric layer, a solar-radiation absorbing layer, a second dielectric layer and an overcoat layer, the order of the layers moving away from the glass substrate. The overcoat layer forms the outmost layer of the multilayer stack and protects the underlying stack from abrasion, scratch and chemical damages both during manufacturing as well as use of the coated glass pane in vehicle window openings that include windscreens, rear window glazings, side window glazings and roof glazings. Further the multilayer stack is engineered to provide an aesthetically appealing experience for the passengers seated inside the vehicle while also retaining the performance characteristics of the glazing.

Summary of the Disclosure

In one aspect of the present disclosure, a solar protective vehicle glazing comprising at least one glass pane of coated glass is disclosed. The coated glass pane comprises a multilayer stack comprising a first dielectric layer, a second dielectric layer, a solar-radiation absorbing layer and an overcoat layer on the glass face which faces the compartments of the vehicle. The solar-radiation absorbing layer is a nitride of a metal alloy comprising nickel and chromium placed between said first dielectric layer and said second dielectric layer. The solar-radiation absorbing layer has nickel and chromium present in a ratio from >60: > 10 to <90: <40. The first and second dielectric layers comprises of a material selected from the group consisting of silicon oxide, aluminum oxide, silicon nitride, aluminum nitride, a mixed aluminum-silicon nitride, silicon oxynitride or aluminum oxynitride. The overcoat layer comprises of a material selected from the group consisting of titanium oxide, titanium zirconium oxide, titanium zirconium hafnium nitride or silicon oxide.

In other aspect of the present disclosure, the solar protective vehicle glazing is bendable and/or toughenable.

In another aspect of the present disclosure, the solar protective vehicle glazing is partially opacified by a coating in the form of a lacquer or an enamel.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

Embodiments are illustrated by way of example and are not limited to those shown in the accompanying figures.

FIG. 1 illustrates a solar protective vehicle glazing, according to one embodiment of the present disclosure;

FIG. 2 illustrates a solar protective vehicle glazing, according to another embodiment of the present disclosure; and FIG. 3 illustrates calorimetric variation of coated glass samples after linear abrasion test, according to the present disclosure.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the invention.

Detailed Description

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. Embodiments disclosed herein are related to solar protective vehicle glazing having enhanced durability & improved passenger experience with aesthetically pleasant reflectance colors.

A solar protective vehicle glazing of the present disclosure comprises at least one coated glass 100, which according to one embodiment of the present disclosure is illustrated in FIG. 1. The coated glass 100 comprises of a glass substrate 110 provided with a multilayer coating 200 on the glass face facing the internal compartments of the vehicle, for selectively blocking the solar radiation. The thickness of each of the layers of the multilayer coating 200 is selected so that the coated glass 100 has a visible light transmission of at least 50%; and a solar factor of at most 75%. In addition, the layers of the multilayer coating 200 are engineered in such a way that the coated glass 100 gives an aesthetically pleasant greyish or bluish grey color external reflection on the glass face exposed to the outside environment and a neutral color internal reflection on the coated side of the glass substrate 110 facing inside the vehicle. Above all the said properties, the multilayer coating 200 exhibits utmost robustness to abrasions, scratches and provides resistivity to the coated glass 100 from all major chemical damages. Therefore, the resulting multilayer coating 200 has an enhanced life span that keeps vehicle glass replacements at bay.

Such a coated glass 100 having a high visible light transmissivity, good solar energy screening properties, appealing aesthetics and enhanced durability can be made to a suitable size and shape for incorporation into vehicle window openings such as windscreens, rear window glazings, side window glazings and roof glazings. While rear window glazings, side window glazings and roof glazings are monolithic, the windscreens are laminated. For the monolithic glazings the multilayer stack 200 is on the face of the glazing oriented towards the passenger compartments and for the laminated glazing the multilayer stack 200 are usually on face 2, 3 or 4 of the glazing, the faces of the glass being numbered from outside to the inside of the vehicle.

Nevertheless, said coated glass 100 can further be useful to architects for use in the exterior facade of buildings. In which case, the coated glass 100 has aesthetic qualities in reflecting the immediate environment and being available in a pleasant color for design opportunities as well having a neutral internal color for comfort of the building occupants. Such coated glass 100 also have technical advantages by providing the occupants of a building with protection against solar radiation by absorption and eliminating the dazzling effects of intense sunshine, giving an effective filter against glare, enhancing visual comfort and reducing eye fatigue. Depending on the intended use, certain desired properties may be altered.

The glass substrate 110 can be made of a clear glass or a tinted glass of 4 mm thickness. The choice of the glass substrate 100 influences the properties of the coated glass 100. In one embodiment of the present disclosure, a green tinted 3.5 mm glass is used as the substrate for depositing the multilayer coating 200. The multilayer coating 200 comprises of a solar-radiation absorbing layer 120 sandwiched between a first and second dielectric layer 130a, 130b and further an overcoat layer 140 placed above the second dielectric layer 130b away from the glass substrate 110. The first dielectric layer 130a is in direct contact with the glass substrate 110 and the second dielectric layer 130b is provided above the solar- radiation absorbing layer 120. The first and second dielectric layers 130a, 130b regulate the reflection, transmission and tint properties of the solar protective vehicle glazing 100 while the overcoat layer 140 protects the underlying layers against mechanical and chemical impairments. The solar-radiation absorbing layer 120 comprises of a nitride of a metal alloy comprising nickel and chromium. This solar-radiation absorbing layer 120 is sputtered with Ar and N2 gas from a target consisting of nickel and Chromium alloy. In one specific embodiment of the present disclosure, the Ni/Cr ratio present in the target to sputter absorbing layer 120 is 80:20. The nickel and chromium present in the target can have a Ni/Cr ratio varying from >60: > 10 to <90: <40. In one particular aspect of the present embodiment, the Ar:N2 gas ratio varies from 80:20 to 20:80. Said ratio of the Ar:N2 gas during sputtering plays a significant role in controlling the color shift of the coated glass 100 after tempering and further assists in ensuring selective blockage of solar radiation

The solar-radiation absorbing layer 120 according to multiple embodiments of the present disclosure, comprises from 40 % to 90 % of nickel; 10% to 20% of chromium and 20% to 50% of nitrogen. According to specific embodiments, the atomic concentration of elements present in the solar-radiation absorbing layer 120 is about 51% of nickel; about 15% of chromium and about 32% of nitrogen.

The thickness of the solar-radiation absorbing layer 120 is particularly maintained low in order to obtain a visible luminous transmission greater than 50%. In one embodiment of the present disclosure, the thickness of the solar-radiation absorbing layer 120 is less than 5 nm. The present disclosure particularly maintains a reduced thickness of the solar-radiation absorbing layer 120 in order to transmit a reasonable proportion of visible light so as to allow natural illumination to the interiors of the building or vehicle and in order to allow its occupants to see out. Thus it is desirable to increase the selectivity of the coating, that is to increase the ratio of the transmittance to the solar factor. Indeed, it is preferred that the selectivity be as high as possible.

The combination of nickel and chromium present in the solar- radiation absorbing layer 120 provides the coated glass 100 with the advantageous combination of a high solar factor and low emissivity. The multilayer stack 200 of the present disclosure achieves a solar factor (SF) of less than 75% and an emissivity value of less than 90%. A low solar factor and a low emissivity value enhance user thermal comfort levels. Further, these properties play a major role in fuel economy of the vehicle by reducing the workload of the vehicle’s air conditioner.

The first and second dielectric layers 130a, 130b are based on silicon oxide, aluminum oxide, silicon nitride, aluminum nitride, a mixed aluminum-silicon nitride, silicon oxynitride or aluminum oxynitride. In a specific embodiment, the first and second dielectric layers 130a, 130b is silicon nitride. The presence of the first dielectric layer 130a on the glass substrate 110 has the particular benefit of inhibiting the migration of sodium ions from the glass substrate 110 by diffusion or otherwise into the solar-radiation absorbing layer 120 either during formation of that solar-radiation absorbing layer 120 or during a subsequent high temperature treatment.

The thickness of the first and second dielectric layers 130a, 130b are modified in such a way that the reflection color on the face of the glass substrate 110 facing the external environment is grey or bluish grey. This is verified by the coated glass 100 having a* _ext value ranging between 1- and -5 and b* _ext value ranging between -3 and -8. Alongside this, the reflection color of the face of the glass substrate 110 facing inside the compartments of the vehicle is maintained to be very neutral, wherein the a* _mt , b* _mt values range between 0 and -3.3. This helps to avoid discomfort to vehicle occupants especially during night where there is an internal source of light present inside the vehicle and the reflectance of the glass does not interfere with the light source inside the vehicle. Accordingly, the first dielectric layer 130a has a thickness ranging between 10 nm to 30 nm and the second dielectric layer 130b has a thickness ranging between 20 nm to 50 nm.

The overcoat layer 140 is based on titanium oxide, titanium zirconium oxide, titanium zirconium hafnium nitride or silicon oxide. The primary function of the overcoat layer 140 is the mechanical and chemical protection of the underlying layers of the multilayer stack 200. Depending on its thickness as well as that of the underlying layers, it may also have an interferential role and thus contribute to the reflection aspect of the coated glass 100. Its thickness is at most 10 nm and preferably at least 5 nm. The actual thickness is chosen depending on the desired properties of the coated glass 100, bearing in mind the desirability of satisfactory visible light transmissivity coupled with efficient energy screening and suitable abrasion resistance.

The extent to which light is absorbed by the coated glass 100 increases with the thickness of the multilayer stack 200, but it is also necessary to take account of the interference effect of light which is reflected at the faces of the multilayer stack 200. The addition of the overcoat layer 140 above the second dielectric layer 130b does not increase the overall thickness of the multilayer stack 200 effectively because of the very thin solar-radiation absorbing layer 120 which otherwise as in the prior art references are always more than 10 nm, especially at least more than 5 nm.

In one embodiment of the present disclosure, all the layers of the multilayer stack 200 are deposited one by one on the glass substrate 110 preferably by magnetron sputtering technique in a reactive atmosphere, but could be carried out by any vacuum deposition technique allowing good control over the optical performance of the various layers in the multilayer stack 200.

The layers of the multilayer stack 200 must also lend themselves to the forming of window glazings for vehicles. These are subjected to heat treatments during fabrication, especially the bending of coated glass, or during toughening intended to give the coated glass reinforced mechanical properties. The layers of the multilayer stack 200 described in the present disclosure withstand these treatments without their properties being degraded. These treatments include temperatures which exceed 630° C for about 10 minutes. The layers of the multilayer stack 200 conserve their properties when subjected to such extreme temperatures.

For glazings used in vehicles and also in building applications, it is extremely important to be capable of withstanding such heat treatments without their color being substantially modified, both in transmission and in reflection. Accordingly, the solar protective vehicle glazing of the present disclosure has a colorimetric variation in transmission (DE*t), glass side-reflection and coating side-reflection (AE* _Rg & AE* _Rc ) less than 2, when the coated glass 100 is subjected to a temperature above 630° C and below 670° C for a time period of 7 - 10 minutes.

Thus the present invention presents the advantage of simultaneously providing a solar factor (FS) below 75%, an emissivity of less than 90% (preferably less than 80%), a luminous transmittance (TL) of more than 50%, neutral internal reflection and pleasant grey or bluish grey color external reflection. Thus the coated glass 100 resists the passage of solar heat into the vehicle and thus avoids overheating inside the vehicle, because of its low solar factor. All this without compromising the aesthetical appeal of the glazing and exhibiting improved increased durability.

A solar protective vehicle glazing comprising of a coated glass 100 according to one specific embodiment of the present disclosure is illustrated in FIG. 2. The coated glass 100 illustrated here is heat treatable and exhibits a bluish grey reflection color in the face of the glass substrate exposed to the external environment and a neutral internal reflection color increasing visual comfort of passengers seated inside the vehicle fitted with such a glazing. The transparent glass substrate 110 is provided with a multilayer coating 200 comprising a nickel chromium nitride layer 120 sandwiched between two dielectric layers 130a, 130b based on silicon nitride. An overcoat layer 140 made from titanium oxide is placed over the second dielectric layer 130b based on silicon nitride. The nickel chromium nitride layer 120 is very thin ranging in thickness between 0.1 nm and 5 nm. The nickel chromium nitride layer 120 absorbs the infrared radiation from the sun and attributes to the solar control properties of the heat treatable solar protective vehicle glazing.

While the solar control properties depend entirely on the thickness of the nickel chromium nitride layer 120, the light transmission (T _L ) of the heat treatable solar protective vehicle glazing is invariably proportional to the thickness of the nickel chromium nitride layer 120. Hence it becomes important to have a balance between the solar control properties and the light transmission (T _L ) values of the heat treatable solar protective vehicle glazing. Thus a thickness range between 0.1 nm and 5 nm of the nickel chromium nitride layer 120 provides for the desired light transmission (T _L ) while also maintaining the solar control properties of the heat treatable solar protective vehicle glazing.

The thickness of the silicon nitride layer 130a present above the transparent glass substrate 110 ranges between 10 nm and 30 nm and the thickness of the silicon nitride layer 130b present above the nickel chromium nitride layer 120 ranges between 20 nm and 50 nm. The silicon nitride dielectric layer 130a, 130b contribute to the reflection color of the heat treatable solar protective vehicle glazing and hence are designed in such a way to provide thermal and visual comfort to the passengers sitting inside the vehicle fitted with such a glazing. The multilayer coating 200 has -13% external reflection and provides a very subtle appearance. In one aspect of the embodiment, the heat treatable solar protective vehicle glazing may be enameled. In multiple aspects of the embodiment, the heat treatable solar protective vehicle glazing may be subjected to strengthening, toughening or bending by exposing the glazing to a temperature not exceeding 670 °C.

The multilayer coating 200 is heat treatable and the transparent glass substrate 110 coated with the multilayer coating 200 can be heat treated to a temperature as high as 630 °C for about 10 minutes. The DE* value (change in color of the heat treatable solar protective vehicle glazing before and after heat treatment) is less than 2.

The solar protective vehicle glazing, according to one embodiment of the present disclosure can be constituted as a laminate in which the coated glass 100 is bonded to at least one other glass pane through an intervening adhesive material. In which case the multilayer stack 200 is placed inside surface of the exterior laminate. Such laminated glazings afford advantages of safety especially when used in a vehicle windscreen. A further advantage of the use of laminate is that it enables the solar radiation screening coating to be located within the thickness of the laminate where it is protected against abrasion during use. In another embodiment of the present disclosure, the solar protective vehicle glazing when used as windscreens can be enameled on the PCB region for obtaining opaque black edging. Example 1

Different multilayer coating according to the teachings of the present disclosure were sputtered over 3.5 mm glass substrates which were of two types viz., clear glass substrate Planilux India™ and a green tinted glass substrate Parsol H™ both manufactured by Saint-Gobain India Private Limited. The specification of the multilayer coatings are as follows:

Tablel: Multilayer Stack for Solar Protective Vehicle Glazing

Optical and solar control properties of the above mentioned glass samples 1 and 2 are summarized in Table 2.

Table 2: Optical & Solar Control Properties

R _ext =External reflection; a*G, b*G=a*, b* values measured on the external side, i.e., the glass side; Ri _nt =Internal reflection; a*C, b*C=a*, b* values measured on the internal side, i.e., the coating side

Sample 1 and 2 have the same multilayer stack deposited on a tinted and a clear glass substrate, respectively to demonstrate the effect of the substrate on the optical and performance properties of the coated glasses. The thickness of the layers of the multilayer stacks are optimized for obtaining the desired optical and performance properties depending on the type of the glass substrate used for the sputtering. The reflection color obtained on the inside of the vehicle is kept as neutral as possible with a*int = -0.5, b*int = -1 to improve the visual comfort of the passengers. The external reflection color of the coated samples are also a pleasant grey or bluish grey obtained from a*ext = -4, b*ext = -7. The solar factor of 51% exhibited by sample 1 provides a maximum of 27% drop over the base glass substrate use. Thus the coated glass produced from the multilayer stack provided according to the teachings of the present disclosure efficiently block solar radiation.

Higher luminous transmission (T _L ) levels are obtained by further reducing the thickness of the solar-radiation absorbing layer while not compromising on the reflection colors of the coated glass product (shown in sample 3) as shown in Table 3.

Table 3: Optical & Solar Control Properties

R _ext =External reflection; a*G, b*G=a*, b* values measured on the external side, i.e., the glass side; Ri _nt =Internal reflection; a*C, b*C=a*, b* values measured on the internal side, i.e., the coating side

Example 2

Heat treatments

Glass samples coated with the multilayer stacks were heated to a temperature of 630 °C for about 7 minutes. The change in reflection color & transmission color (DE*t _& DE*k) of the coated substrates post the heat treatment was measured.

Table 4: Calorimetric Variation

It is evident from the table that both the later stacks 1 and 2 have DE* values less than or equal to 1 in both color and transmittance. This property brings high color matchability between heat treated and the untreated coated glass samples of the present disclosure.

Comparative Example 1

From the comparative example 1 constructed from U.S. patent 6,926,967 herein incorporated as reference to samples 1 to 3 of the present disclosure, it can be seen that the absence of overcoat layer and thicker functional layer (thickness greater than 5 nm) resulted in high internal reflection values (more than 30% from the examples illustrated in the patent) and the internal reflection color turning to golden yellow instead of the desired neutral color (note the highly positive internal reflection b* for the comparative example). Very high internal reflection value and color lead to discomfort for people sitting near the window of a vehicle body. Further, the strong yellow shade might be disturbing. It must be appreciated that the thinner functional layer and introduction of the overcoat layer unexpectedly improved the desired characteristics as illustrated here and in previous sections. The internal reflection color according to the present disclosure is engineered to be neutral (where a*C and b*C is very close to the origin) and at the same time internal reflection was kept low (15 - 16%).

Example 3

Durability Studies

Considering that the coated glass samples are aimed to be used as automotive glazings, it is inevitable that the samples have good abrasion and scratch resistance. The following durability studies were performed for the coated glass substrates samples of the present disclosure.

Erichsen Brush Test

The brush test was used to evaluate the resistance of the coated glass samples to abrasion caused by a nylon brush used as the abrader. In this test a soft nylon brush is rubbed against the coating where the coating is submerged in the water. This test is done to test mechanical robustness of the multilayer stack of the present disclosure against washing machine brushes during processing.

The samples were tempered at a temperature of 630 °C after the Erichsen brush test. This step reveals the presence of any minor scratches that occurred during the test procedure. However, the tested samples did not show any sign of scratches.

In another experiment, the coated samples were first tempered at a temperature above 630 °C and then subjected to the Erichsen brush test procedure. Again the samples did not show any sign of minor scratch or coating erosion. Further the calorimetric variation was measured to be less than 2.

Taber Abrasion test

Taber abrasion test was used for performing accelerated wear resistance testing. It involved mounting a flat coated glass sample of approximately 100 mm ² to a turntable platform that rotate on a vertical axis at a fixed speed. The wear action was carried out by two rotating abrading wheels supported on a loading arm which applied 250 grams pressure against the specimen, exclusive of the weight of the wheel in contact with the coated glass sample. The transmission before and after the test were measured to calculate the overall change in transmission of the test samples. The results of mechanical durability studies are summarized in Table 5.

Table 5: Results of Durability Studies

Chemical Resistivity

The coated glass samples passed the chemical durability testing performed using the EN 1096 norm.

Linear Abrasion Resistivity Testing in Dynamic Conditions

In order to mimic the door glass movements in a vehicle and evaluate the abrasion resistivity of the coated glass samples against the sealing lip of the vehicle door, a sealing lip was designed and used as the abrader for up to 10,000 cycles of testing under dynamic conditions of dry, water, oil and dust.

Sealing lip abrasion against the coated glass samples of the present disclosure in dry condition, while the coated glass samples are immersed under water and while the coated glass samples were coated with a layer of oil were tested. Sealing lip abrasion against the coated glass samples overlaid with dust particles were also tested. In all the above conditions the abrasion was tested after 2000, 5000 and 10,000 cycles. The calorimetric variations in the coated samples were measured by measuring the reflection color and transmission color before and after the abrasion testing. Results of the calorimetric variations measured are illustrated in FIG. 3. The criteria for evaluation was taken as follows: AE* _R <2.6 was considered to be good; 2.6£DE*k was considered to be moderate and DE* R >5 caused severe damage to the multilayer coating. From FIG. 3 it is clear that the calorimetric variation of all the coated glass samples tested were within the limits and the multilayer coating of these samples were not severely affected.

The overcoat layer 140 of the multilayer stack 200 of the present disclosure protects the underlying stack from the abrasion and scratch generated from the above experiment. Glass samples prepared with a multilayer stack comprising Si3N4/NiCrN/Si3N4, without the overcoat layer 140 of the present disclosure do not exhibit such enhanced abrasion and scratch resistance as illustrated by the glass samples prepared according to the teachings of the present disclosure provided with multilayer stack comprising Si3N4/NiCrN/Si3N4/Ti02. Thus, the overcoat layer is significant for providing enhanced mechanical durability to the glass samples while retaining other desired characteristics of the glazings described in the starting of this disclosure.

It should be noted that the above examples are only indicative and were incorporated in the specification for teaching purpose only and further does not limit the scope of the invention in any manner.

Industrial Applicability

The solar protective heat treatable glazing described in the present disclosure finds application as a glazed element in vehicles: sunroof, windshield, side window, rear window and a glazing element of building. The solar protective vehicle glazing of the present disclosure has advantage of simultaneously providing a solar factor (FS) below 75%, an emissivity of less than 90 (preferably less than 80%), a luminous transmittance (TL) of more than 50%, neutral internal reflection and pleasant grey or bluish grey color external reflection. As already indicated above, the glazing according to the present disclosure obviously also finds its application as a glazed element of a building. In this application case, the glazing may form a double or triple glazing with the multilayer stack arranged facing the closed space inside the multiple glazing. The glazing may also form a laminated glazing whose multilayer stack may be in contact with the thermoplastic adhesive material connecting the substrates, in general PVB. The glazing according to the invention is, however, particularly useful when the multilayer stack is facing the outer environment, whether it is a single glazing or a laminated glazing, but also optionally a multiple glazing.

The solar protective vehicle glazing of the present disclosure can also be enameled, strengthened or toughened. The extensive durability of the solar protective vehicle glazings provides for an extended life of the product.

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Certain features, that are for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in a sub combination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

The description in combination with the figures is provided to assist in understanding the teachings disclosed herein, is provided to assist in describing the teachings, and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application.

As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such method, article, or apparatus. Further, unless expressly stated to the contrary, "or" refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

Also, the use of "a" or "an" is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for that more than one item.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent that certain details regarding specific materials and processing acts are not described, such details may include conventional approaches, which may be found in reference books and other sources within the manufacturing arts.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

List of Elements

TITLE: A SOLAR PROTECTIVE VEHICLE GLAZING

100 Coated Glass

110 Glass Substrate

120 Solar Radiation Absorption Layer

130a Dielectric Layer

130b Dielectric Layer

140 Overcoat Layer

200 Multilayer Coating