Field of the Disclosure

The present disclosure relates to the field of transparent conductive coated automotive glazing with laser ablation formed frequency selective surfaces.

Background of the Disclosure

As the automobile manufacturers strive to improve the efficiency of their vehicles, in response to regulatory requirements for fuel economy and consumer demand for environmentally friendly vehicles with increased levels of comfort and convenience, the use of glazing with solar control coatings has been growing at a rapid rate. Once limited to a small segment of the market, we now are seeing solar control coated glazing offered as an option and even as standard equipment on more and more models.

Another area of high growth has been in the electronic content of automobiles which has grown at a higher rate than any other category of technology. Today, most vehicles have a high-speed data network running throughout them. Rather than making a contact that closed a circuit and sends power to a device, when a switch is pressed, it most likely is sending a message over the network to a controller. In particular we have seen a proliferation of wireless devices, both OEM and aftermarket. These include but are not limited to, cellular phones, 5G, Global Positioning Systems (GPS), satellite radio, radar detectors, wi-fi, tire pressure sensors, garage door operators, adaptive cruise control, and toll road transponders. The list continues to grow as new technologies are deployed as the industry moves incrementally towards level V autonomous operation and full electrification of the drive train across most new models.

The set of electromagnetic spectrum frequencies ranging from 20 KHz to 300 GHz comprises the radio frequency (RF) portion of the spectrum. Most of the wireless electronic devices used in vehicles to transmit and/or receive information operate in the RF range.

Herein, at the intersection of these two trends, lies the challenge which we will now discuss.

Automotive glazing often makes use of heat absorbing glass compositions to reduce the solar load on the vehicle. While a heat absorbing window can be very effective the glass will heat up and transfer energy to the passenger compartment through convective transfer and radiation. A more efficient method is to reflect the heat back to the atmosphere allowing the glass to stay cooler. This is done using various infrared reflecting films and coatings. Infrared coatings and films are generally too soft to be mounted or applied to a glass surface exposed to the elements. Instead, they must be fabricated as one of the internal layers of a laminated product to prevent damage and degradation of the film or coating.

One of the big advantages of a laminated window over a tempered monolithic glazing is that a laminate can make use of these infrared reflecting coatings and films in addition to heat absorbing compositions and interlayers.

The energy from the sun reaching the surface of the earth is comprised of 3% ultra-violet rays (UV), 55% infra-red radiation (IR) and 42% visible light. Ordinary clear glass only transmits 90-95% in the visible so it is possible to produce a glazing that only transmits 40% of the total incident solar radiation by using such coatings. By further reducing the visible light transmission even lower values of total solar energy transmitted can be obtained. Windshields are in the market that while passing over 70% of the visible light only allow 30-35% of the total solar energy into the cabin. The total transmission in the solar range (TTS), as defined by ISO 13837, corresponds to the direct solar light portion measured from 300 to 2500 nm and a term comprising the emissivity.

Infrared reflecting coatings include but are not limited to the various metal/dielectric layered coatings applied though Magnetron Sputtered Vacuum Deposition (MSVD) as well as others known in the art that are applied via pyrolytic, spray, controlled vapor deposition (CVD), dip, and other methods.

By far, the silver based MSVD family of solar control coatings have the best solar performance. When used in an insulated glass unit they also have low-emissivity (low-e) properties. Studies have shown that replacing a standard windshield with a coated windshield can improve fuel efficiency by 5% due to the reduction in the power drawn by the air conditioning on warm days. This improves energy efficiency and extends the range of the vehicle, which is a major consideration and benefit on internal combustion engine (ICE) vehicles and even more so with full electric battery powered vehicles.

On marginally warmer days where the air conditioning is not needed, solar coated glass also helps by allowing the vehicle to remain comfortable and operate with the windows closed, substantially reducing drag. Such improvements are especially noticeable in case of solarcontrol coated panoramic roofs.

Solar control coatings work by making the glass highly reflective in the infrared. This prevents a substantial percentage of the sun’s energy from entering the vehicle. This is done by applying a coating to the glass which comprises at least one electrically conductive metallic layer. Most of the commonly used automotive solar coating are silver (Ag) based coatings. Normally, when a thin layer of silver is deposited on a glass substrate, a mirror is produced which is high reflectivity in the visible. This is caused by the large difference between the index of refraction of the thin silver layer and that of the glass substrate. The higher the difference, the more reflective a surface becomes. By means of the careful selection of the materials used for the layers adjacent to the silver and their index of refraction, the reflectivity can be tuned such that the silver layer is rendered substantially transparent in the visible portion of the spectrum and highly reflective in the infrared wavelength range.

On the flip side, the conductive layers of such coatings reflect and attenuate radio frequency (RF) radiation, thus interfering with the operation of the various wireless devices used to communicate with the outside world. Even though the actual metal layers of the coating are only nanometers in thickness, they reflect substantially the radio frequency energy, especially that in the Gigahertz (GHz) range.

Experiments were conducted using 300 mm by 300 mm test coupons comprising typical windshield thickness laminated glass (two 2.1 mm soda-lime glass layers laminated with a clear 0.76 mm PVB plastic bonding layer) with a silver based solar control coating with silver layers totaling about 35 nm in thickness. With broadband horn antennas located in close proximity to the glass, over a range of 800 MHz to 3 GHz, the attenuation measured was indistinguishable for that of a solid 3 mm thick aluminum plate of the same dimensions.

Some RF devices that do not require a direct line of sight and which have sufficient dynamic range may still be able to function although with reduced range due to the smaller amount of RF energy that is transmitted through the glazing, and which enters the passenger compartment through other secondary paths. Devices like toll transponders, GPS, and radar detectors, which typically are mounted to the glass or in close proximity to the windshield, will not reliably function if at all with a metallic based coated windshield.

One solution is to provide an area on the glazing where there is no coating. This aperture can be made by masking the glass surface prior to the application of the coating or by removing the coating from the area after the glass has been coated. Most silver based solar coatings are soft and easily removed by means of an abrasive process. Many coated windshields have been produced with an uncoated region near the top center of the windshield used for toll transponders. A black obscuration or black dot pattern is often used to hide this area where the coating has been deleted. The toll transponder region is also further hidden by the dark sunshade also often used on windshields.

However, the lack of coating in the aperture will compromise the solar characteristics of the glazing in the area where the coating is absent. TTS in this case is increased to the same level as for uncoated glass. The uncoated area will also tend to have poor aesthetics as it will be immediately obvious visually due to the very different optical properties of the coating versus the uncoated glass.

Most of today’s automotive laminates are made by heating the glass layers using radiant electrical heat. This is done so as to allow for the very precise heat profiles needed to achieve the complex shapes required. Due to the thermal gradient that will result from the abrupt change from heat reflecting to heat absorbing caused by the transition from coated to uncoated, distortion is likely. In addition, the heat profile tends to run hotter towards the center of the part while the areas near the edge are the coolest. If the area where the coating is absent is near an edge it may not be too difficult to bend the glass and the distortion may be minimal. As we move further away from the edge of glass, the higher temperatures result in higher gradients, and it may become impossible to fabricate an acceptable part.

Silver based coatings are also easily removed by means of laser ablation of the coating. In this case the coating can be removed partially such that the area that the coating was removed from forms an aperture for RF passage. The size of the aperture must be at least of a wavelength of the frequency that we want to pass. This can be quite large. At FM, with a center frequency of 100 MHz, the wavelength is 3 meters requiring a minimum aperture of 0.75 meters. This is clearly not practical for most glazing. In this spectral range, however, ultra-thin metal-inclusive coatings tend to cause much less attenuation to the RF signal (the attenuation increases with increasing frequency).

In the GHz range, the aperture size is at least an order of magnitude less but as the frequency increases devices become more directional. When we enter into the 5G millimeter range, the path required becomes line of sight requiring that the electronic device emitting or receiving signal must be placed directly behind the aperture. While the size of the aperture does not need to be all that large, we need to make it sufficiently large so as to improve the probability of obtaining a line of sight while accounting for fabrication and assembly tolerances.

A technology, known as FSS, can be used to improve the RF compatibility of transparent conductive coatings without having to create a coating free aperture. These FSS patterns belong to the class of spatial filters.

An example of an FSS can be found on all microwave oven doors. The window on the door is covered with a metal mesh 10, with small circular openings as shown in Figure 5A. The openings let light pass but are sized to block the microwaves (the wavelength of 12.5 cm in this case). This is a band stop FSS filter. If the metal mesh is inverted, with the circular holes replaced by solid metal discs 10, as shown in Figure 5B, we have a band pass filter. Even though a substantial portion of the area is covered with metal, the mesh will let pass most of the energy at the pass frequency. For automotive applications we require a region on the coating which behaves as FSS. It can be made by laser ablating some portions of the conductive coating to create a repeating pattern of conducting and non-conducting areas. Such a patterned coating opens a propagation channel through the glass for certain wavelengths. While there are a number of means that can be used to produce the FSS pattern in the coating, including lithography, laser ablation is a preferred choice due to its high throughput and lower complexity. Modern laser marking systems with high repetition rate lasers can ablate at a rate as high as 10 m per second making it possible to make relatively large complex FSS patterns in a short amount of time.

One of the most commonly used FSS patterns is the rectangular grid pattern as shown in Figure 6B. The rectangular grid is a low pass FSS which has a high cut-off that increases as the size of the rectangles decreases. The relation is linear. For low attenuation in the GHz range, a 1 mm x 1mm rectangle size is used. In the FM radio range, a 3.0 mm x 3.0 mm rectangle has been used successfully. Interestingly, empirical data shows that there is no measurable difference between a 100 pm line and a 50 pm line width in these bands while keeping the center-to-center distance the same. When the rectangles become resonate, they re-emit giving the transmission level a bump.

Figure 6A shows an example of a solar control coated laminated roof with a 300 mm diameter region in the coating having laser ablated FSS pattern. A satellite radio/GPS antenna is mounted to the interior surface of the glass in the FSS area. The FSS is comprised of a 1 mm line to line spacing rectangular grid with a 100 pm line width.

The percentage of the total coating in each rectangle of the FSS pattern region that remains after ablation is called the Fill Factor (FF). The FF is typically in the 80 - 95% range although it can range from 5% to greater than 95%. A high pass FSS used for GHz devices employs 9 mm rectangles marked with a 100 pm wide ablation line. In this case, the FF is -72%. With a 3.0 mm rectangular grid and the same 100 pm wide ablation line, the FF is -98%.

Small line-to-line spacing values, resulting low FFs, are typically associated with the unwanted visibility of the ablated lines. In case of silver based solar-control coatings, for example, these lines have a brownish coloration for two primary reasons: the oxidation of silver edges and the damage to the edges of the troughs of the ablated areas by the laser beam, specifically, by the plume created by the ablation process.

In addition to the aesthetic issues, the brownish dark areas can reduce the total visible light transmission (TL). This is an issue of great concern on coated laminates that are already very close to the regulatory limits TL > 70%.

A number of methods have been developed to minimize this discoloration. A big part of the problem is that most yttrium-aluminum-garnet (YAG) and Fiber lasers have a gaussian power distribution across the beam. There is a minimum power density that is required to ablate a given coating. Anything less will just damage the coating and not remove it

One method that has been used to address this limitation has been to block the outermost portion of the beam so that only the portion that has sufficient power to completely ablate the coating is emitted from the optics.

Another method makes use of at least one additional pass with the beam. The second pass serves to clean up and ablate at least some portion of the damaged coating.

A pulsed laser can fire several thousands of times per second. Each pulse creates a hole in the coating. As we need to break the conductivity of the coating to form the FSS, the holes or spots must overlap. Another method used to reduce coating damage is to increase the overlap from spot to spot. In this manner, each subsequent spot, ablates some of the coating damaged by the previous spot. In Figure 7A, the gaussian power distribution 14 of five spots with an overlap of 50% is shown. The white central area is where the power intensity is sufficient to cleanly ablate the coating. In the darker shaded portions, some coating is left behind. The result is shown in Figure 7B. The ablated line is left with a scalloped edge. As the overlap is increased, the height of the scallops is reduced. The ideal would be to have no coating damage. From a practical standpoint, if the damaged area can be limited to an area that is less than 5% of the spot diameter in width, the line will be virtually invisible under most lighting conditions.

It has also been found that if the beam travels through the glass initially striking the coating at the glass coating interface, i.e. , the bottom of the coating stack, the ablation is much cleaner.

The problem with this approach is that it is difficult to implement a system that can accurately position the laser and maintain the correct focal length and the fact that some coatings are applied to IR absorbing glass or glass that has a coating on both sides.

While all of these methods do reduce the damage, they do not eliminate it. Some of the discoloration is in the areas immediately adjacent to the ablated area and the beam are caused by the intrinsic properties of the coating layers and how they react.

In order to ablate the coating without damaging the glass surface, the laser wavelength must be one at which the substrate is substantially transparent. While a CO2 laser can ablate coating, the energy is absorbed by the glass causing micro- cracking of the glass surface when the power density of the spot is increased sufficiently to ablate the coating. As the coating itself is highly reflective in the IR, that too presents a problem. While an IR laser can ablate the coating, a higher power level is required, and the quality of the ablation is not as good as that of a green or UV laser. The IR laser, however, has the advantage in that YAG and Fiber lasers are commonly available that emit in the IR. While green is very close to ideal resulting in a clean ablation with minimal damage the primary drawback is that the green requires the addition of a frequency doubler with a fiber or YAG laser, thus increasing the reliability, complexity, and cost of the system. A UV laser is marginally better than green but adds even more cost and complexity.

Another advantage of green over I R and U over green is that at the shorter wavelengths, the spot size and minimum line width can be reduced which can improve the aesthetics.

A number of means are used to direct the laser beam onto the coating. For relatively small ablation areas, a fixed laser with a galvo steered beam and an f-theta lens is used. However, the practical marking field size limit is around 300 mm x 300 mm. For larger areas, the laser and galvos can be mounted on an XY gantry or the glass itself can be moved on an XY table. Alternately, multiple lasers can be used concurrently. While some attempts have been made to use a robot to position the laser, robots do not generally have the accuracy required. For less complex patterns or when cycle time is not a major constraint, the galvo may be dispensed with, and the laser positioned on a gantry or the glass on an XY table.

It would be highly desirable to achieve laser-ablated lines in solar control automotive glazing with improved aesthetics and without the other drawbacks of the prior art.

Brief Summary of the Disclosure

The disclosure comprises a solar control coating that has been optimized to reduce the unwanted visibility of laser-ablated areas. This allows for laser ablation of the coating to be done creating frequency selective surface patterns in the coating which facilitate the function of wireless communication devices. The optimization is accomplished by tuning the composition of the so-called sodium (Na) blocking layer to a specific stoichiometry. The disclosure discloses a silicon-oxy-nitride (SiOxNy) layer compositionally tuned between the SiO2 and SisN4 in such a way as to allow attaining just the right properties of the material to perform as a superior sodium barrier as well as to have a substantially reduced residual mechanical stress, thus being resistant to the unwanted damage by laser ablation. Said coating comprises (starting from the glass surface): at least one SiOxNy dielectric layer with a refractive index between 1.90 and 2.00 and at least one functional layer comprising an electrically conducting material at least partially transparent in the visible. Advantages

• Superior aesthetics

• Reduced thermal gradients

• Facilitates larger FSS patterns

• Facilitates more complex FSS patterns

• Lower drop in visible light transmission.

Brief Description of the Several Views of the Drawings

Figure 1 XPS spectra of Si-based Na-blocking layers.

Figure 2 Dependence of the damaged area on the power of laser beam.

Figure 3 An SEM micrograph of a laser-ablated coating.

Figure 4 Stress and damage as functions of refractive index

Figure 5A Band stop filter

Figure5B Band pass filter

Figure 6A Panoramic roof with 300 mm diameter FSS.

Figure 6B Closeup of 1 mm x 1 mm grid pattern FSS.

Figure 7A Power distribution of beam.

Figure 7B Coating damage from ablation.

Reference Numerals of Drawings

10 Metal

12 Coating damage

14 Gaussian distribution

16 Laser ablated area

20 Laser ablation optimized coating

22 Ablation line

Detailed Description of the Disclosure The present disclosure can be understood more readily by reference to the detailed descriptions, drawings, examples, and claims in this disclosure. However, it is to be understood that this disclosure is not limited to the specific compositions, articles, devices, and methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing aspects only and is not intended to be limiting.

The following terminology is used to describe the laminated glazing of the present disclosure.

The typical automotive laminated glazing is comprised of two layers of glass, glass one and glass two. The two glass layers are permanently bonded together by a plastic layer (interlayer). In a laminate, the glass one surface that is on the exterior of the vehicle is referred to as surface one. The opposite face of glass one layer is surface two. The glass surface that is on glass two is referred to as surface four. The opposite face of glass two layer is surface three.

Surfaces two and three are bonded together by the plastic layer.

An obscuration may also be applied to the glass. Obscurations are commonly comprised of black enamel frit printed on either surface two, surface four, or on both. The laminate may have a coating on one or more of the surfaces.

The structure of the present disclosure is described in terms of the layers comprising the glazing. The meaning of “layer,” as used in this context, shall include the common definition of the word: a sheet, quantity, or thickness, of material, typically of some homogeneous substance and one of several.

When multiple layers that vary widely in thickness are illustrated, it is not always possible to show the layer thicknesses to scale without losing clarity.

The term “glass” can be applied to many inorganic materials, including many that are not transparent. For this document we will only be referring to transparent glass. From a scientific standpoint, glass is defined as a state of matter comprising a non-crystalline amorphous solid that lacks the ordered molecular structure of true solids. Glasses have the mechanical rigidity of crystals with the random structure of liquids.

The types of glass that the coating may be applied to include but are not limited to the common soda-lime variety typical of automotive glazing as well as aluminosilicate, lithium aluminosilicate, borosilicate, glass ceramics, and the various other inorganic solid amorphous compositions which undergo a glass transition and are classified as glass including those that are not transparent. The glass layers may be comprised of heat absorbing glass compositions as well as infrared reflecting and other types of coatings. A glazing is an article comprised of at least one layer of a transparent material which serves to provide for the transmission of light and/or to provide for viewing of the side opposite the viewer and which is mounted in an opening in a building, vehicle, wall or roof or other framing member or enclosure.

Laminates, in general, are articles comprised of multiple layers of thin, relative to their length and width, material, with each thin layer having two oppositely disposed major faces, typically of relatively uniform thickness, which are permanently bonded to one and other across at least one major face of each layer. The layers of a laminate may alternately be described as sheets or plies. In addition, the glass layers may also be referred to as panes.

The list of coating layers is called the coating stack. When describing a coating stack, we shall use the convention of numbering the coating layers in the order that they are deposited upon the substrate. Also, when discussing two layers, the one closest to the substrate shall be below or under the second layer. The layer furthest from the substrate is over or above the second layer. Likewise, the top layer is the very last layer applied and the bottom layer is the very first layer deposited upon the substrate. The top of an individual layer is the side of the layer furthest from the substrate while the bottom is closest to the substrate.

The terms region and area are used interchangeably when describing the area of the coating that was ablated by laser.

While the focus of the embodiments and discussion is laminated windshields and roofs, it can be appreciated that the present disclosure is not limited to laminated windshields and roofs. The present disclosure may be implemented in any of the other glazing positions in the vehicle. In addition, the present disclosure may be practiced with any type of glazing and is not limited to automotive.

In the same manner, while the embodiments described and the discussion are primarily focused on silver as the conductive layer, other metals may be used. Pure metallic silver (Ag) may be and is often used for the conductive layer. However, the silver may be alloyed with at least 0.1 wt.% of one of the metals from the following list: Pt, Pd, Ti, Ni, W. In the same manner the conductive material may comprise Indium-Tin-Oxide or another transparent conductive oxide. All of these will be viewed as an equivalent.

To characterize the electrical performance of thin conductive materials, the physical attribute called sheet resistance is typically used. The sheet resistance is defined as the bulk resistivity divided by the layer thickness, is dimensionally unitless, and is specified in ohms per square.

The laser ablation optimized coating of the disclosure will have a sheet resistance ranging from 0.3 ohms/sq to 100 ohms/sq. Stoichiometry relates to the chemical composition of a compound. If a compound is stoichiometric, it means its composition perfectly follows its mathematical formula, e.g., a fully oxidized zinc oxide (ZnC>2) deposited from a metallic target in oxygen atmosphere. In a more general way, the formula of zinc oxide is referred to as ZnOx.

The disclosure discloses a solar control coating that has been optimized to reduce the damage and discoloration of the coating caused by the laser ablation process along with the unwanted visibility of laser-ablated areas. By improving the aesthetics of the laser ablated regions, they can be made more complex, larger and be located where it may not have been possible or practical to locate with the coatings of the prior art.

A typical solar control coating, such as an Ag-based coating, comprises at least one ultra-thin and substantially transparent metal layer sandwiched between at least two dielectric layers. Besides playing as an optically active element of the stack, one of the primary goals of the dielectric adjacent to the glass substrate is to provide sodium-blocking properties. Indeed, typical soda-lime glass contains between 16 and 17 wt. % of Na (sodium) in the form of sodium dioxide.

During the magnetron-sputter vapor deposition (MSVD) of thin-film stack and, especially, during post-deposition high-temperature treatment, such as that during the bending process at -630 °C, sodium ions are known to diffuse out of the glass and into the stack, thus affecting the optical and electrical properties of the silver and other layers. In this regard, the first layer of the stack - the one adjacent to the glass substrate - is often called the sodium blocker and is typically intentionally designed for that purpose.

The sodium blocker of a typical solar control coating is a silicon-based sputtered layer, such as silicon dioxide (SiC>2) or silicon nitride (SisN^. Some aluminum (Al) is often added to the silicon (Si) sputtering targets to achieve higher deposition rates. The Na-blocking properties of SiC>2 strongly depend on the presence of Al in the film. A high enthalpy of aluminum oxide formation (-1675 kJ/mol) leads to Al atoms being incorporated into the Si-0 bond of SiO2 instead of simply replacing Si atoms. This results in the formation of extended (SiAIO) bonds, which compromise the blocking properties of SiO2 by creating the migration channels for Na.

At the same time, SisN4 has been reported as a good barrier (Z. Wan, et al., Energy Procedia 10 (2011) 271 - 281), but a challenging material as far as laser ablation is concerned due to its high residual stress (G. Poulain et al., Energy Procedia, Volume 27, 2012, Pages 516-521 ; B. Soltani, et al., Optics & Laser Technology Volume 119, November 2019, 105644).

The authors of the present disclosure discovered that tuning the composition of the sodium blocking layer to a specific stoichiometry between the SiO2 and SisN4 allows attaining just the right properties of the material to perform as a superior sodium barrier as well as being resistant to the unwanted visible damage by laser ablation.

Figure 1 presents the X-Ray Photoelectron Spectroscopy (XPS) spectra of five 80 nm thick Si-based Na-blocking layers sputter-deposited on the air side (the top layer of glass during the float production process) of soda-lime glass.

In the chart, n denotes the refractive index of the material at 550 nm, and CS stands for Compressive Stress measured in MPa. As it is evident from Figure 1 , SisN4 is superior to SiC>2 in terms of sodium-blocking properties, however, its compressive stress is also the greatest.

SiC>2, on the other hand, is characterized by the least amount of compressive stress but has the poorest Na-blocking properties of the five samples.

The Na-blocking properties of the layers with the intermediate stoichiometry - the SiOxNy - are not linear, i. e., a ‘sweet spot’ is observed at the composition providing a refractive index of at least 1.95. Index reduction of SiOxNy to 1.90 results in a moderate reduction in compressive stress but a significant loss of Na-blocking properties.

Laser ablation was done with a nano-second laser operating at 1064 nm and having a Gaussian power distribution of the beam power. The damage of ablated lines was assessed using an imaging software. Figure 2 represents the dependence of the damaged area on the power of the beam. Based upon Figure 2, the power of 3.5 W was selected as optimal value for the experiment.

An example of the damage by laser beam to the coating can be seen in the Secondary Electron Microscopy (SEM) Image of Figure 3.

As discovered by the inventors, one of the main contributors to the visibly noticeable edges of the laser-ablated lines is a compromised adhesion of the Na-blocking layer to the glass due to the layer compressive stress.

From Figure 4, we can see that there is a good correlation between the level of compressive stress in the film and the amount of sustained damage after the laser ablation. In short, the higher the compressive stress, the higher is the damage caused by laser ablation. In one embodiment of the disclosure, the compressive stress remains below 600 MPa, minimizing potential damage during laser ablation and ensuring optimal performance.

Embodiments

1. Embodiment one is a solar control coating comprising at least one SiOxNy dielectric layer having a refractive index that is in the range of 1.90 to 2.00; at least one functional layer comprising an electrically conducting material; and at least one encapsulating dielectric; wherein said electrically conducting material is at least partially transparent in the visible light spectrum; and wherein said solar control coating has a total sheet resistance in the range of 0.3 Ohms/sq to 100 Ohm/sq.

The solar control coating of the disclosure is optimized for laser ablation, which means that less optical defects are generated onto the coating when it is laser ablated compared to the coating of the prior art. This optimization may be quantified using imaging software. The software evaluates a micrograph of the laser ablated area and calculates the areas measured by electron scanning microscopy and it can be quantified that no more than 10% of the total coated area ablated by laser suffers damage. Therefore, said at least one SiOxNy dielectric layer has to have a compressive stress below 600 MPa so damage can be controlled to acceptable levels.2. Embodiment two comprises an MSVD solar control coating deposited onto at least one major surface of the at least two glass layers of soda-lime glass substrate comprising three silver-based functional layers and a SiOxNy dielectric Na-blocking layer having an index of refraction of 1.90, and sheet resistance of 1 Ohm/sq.

3. Embodiment three comprises an MSVD solar control coating deposited onto a sodalime glass substrate comprising three silver-based functional layers and a SiOxNy dielectric Na-blocking layer having an index of refraction of 1.95, and sheet resistance of 1 Ohm/sq.

4. Embodiment four comprises an MSVD solar control coating deposited onto a sodalime glass substrate comprising three silver-based functional layers and a SiOxNy dielectric Na-blocking layer having an index of refraction of 2.00, and sheet resistance of 1 Ohm/sq.5.

Embodiment five comprises an MSVD solar control coating deposited onto a soda-lime glass substrate comprising two silver-based functional layers and a SiOxNy dielectric Na- blocking layer having an index of refraction of 1.90, and sheet resistance of 3 Ohms/sq.

6. Embodiment six comprises an MSVD solar control coating deposited onto a soda-lime glass substrate comprising two silver-based functional layers and a SiOxNy dielectric Na- blocking layer having an index of refraction of 1.95, and sheet resistance of 3 Ohm/sq.

7. Embodiment seven comprises an MSVD solar control coating deposited onto a sodalime glass substrate comprising two silver-based functional layers and a SiOxNy dielectric Na- blocking layer having an index of refraction of 2.00, and sheet resistance of 3 Ohm/sq.8.

Embodiment eight comprises a laminated glazing, wherein said glazing comprises at least two glass layers and at least one plastic bonding layer. One of said at least two glass layers is coated in at least one area with the coating of any of embodiments one to seven. The solar control coating solar control coating is applied onto at least one major surface of the at least two glass layers which is in contact with the at least one plastic interlayer or in the glass surface which is facing the interior of the vehicle. For example, in the case of a glazing having one inner glass layer, one outer glass layer and one plastic interlayer, the solar control coating of the disclosure may be applied to surface two, three or four. The solar control coating comprises at least one dielectric layer. The solar control coating of the disclosure is laser ablated.

In one inventive aspect of the disclosure, the coated area is laser ablated such as to form two or more distinct and electrically insulated coated areas. Each area may be controlled independently to heat the glazing at different settings.

In a second inventive aspect of the disclosure, the coated area is laser ablated such as to form two or more separate segments for different touch systems, and/or applications, and/or controls.

In a third inventive aspect of the present disclosure, the laser ablation of the coated area can form a pattern which provides the coating the function of being a frequency selective surface and allows specific ranges of communication wavelength to cross through the coated region.

The patterned laser ablated area has a drop in total visible light transmission of no greater than 2% as compared to the non-ablated coated area. More preferably the drop in visible light transmission is below 1%.

The percentage of the total coating in the patterned laser ablated area that remains after ablation is called fill factor and it is between 5 and 95%. More preferably the patterned laser ablated area may have a fill factor of between 80 and 95%.

9. Embodiment nine comprises the large panoramic laminated roof of Figure 6A. The laminate has two glass layers. The outer layer is a 2.7 mm thick ultra-clear soda-lime glass composition. The solar control coating is applied to surface two of the outer glass layer. The inner glass layer is also 2.7 mm thick soda-lime but in a dark solar green composition. A tinted 0.76 PVB interlayer is used to bond the two glass layers to each other resulting in a total visible light transmission of 20%. Surfaces two and four are printed with a 150 mm wide black frit obscuration.

The vehicle is equipped with an active GPS/Satellite radio antenna which is mounted to surface four of the roof centered with the laser ablation region.

The laser ablation pattern facilitates the propagation of RF signals through the coated glass and is done in the transparent area of a roof with a pulsed, 10-Watt, 5 ns pulse width, 100,000 pulses per second repetition rate, fiber laser emitting at 1064 nm. The beam is collimated, passed through a beam expander, and then enters a 25 mm aperture on a galvo steering head. The galvo directs the beam into a large f-theta lens resulting in a marking field of 300 mm x 300 mm. The laser ablated pattern is limited to a circular area 16 with a diameter of 300 mm. The FSS pattern comprises a 1 mm x 1 mm square pattern, as shown in Figure 6B, having an FF of 80% with a line 22 width of 100 pm. The resulting coated 20 rectangles are 0.9 mm x 0.9 mm. At a feed rate of 5 meters per second, the entire pattern takes 30 seconds to ablate. The coating is an MSVD triple-silver solar-control coating deposited with an SiOxNy layer having an index of refraction of 1.95 which functions as a Na-blocking layer similarly to embodiment three. About 5% of the area covered by a solar control coating of the roof is laser ablated. After ablation, the drop in total visible light transmission is less than 1 %. RF losses at 2.4 GHz are less than 3dB over uncoated glass. Only 5% or less of the ablated area has coating damage 12.

10. Embodiment ten is a vehicle windshield comprising two glass layers and one plastic interlayer, wherein the solar control coating of this disclosure is deposited one of the two glass layers. The solar control coating comprises two silver-based functional layers deposited with an SiOxNy dielectric Na-blocking layer having an index of refraction of 2.00, and the coating having total sheet resistance of 3 ohms/sq. The area confined to the front-view camera zone located in the upper part of the driver-view or above it, was laser ablated in a pattern. The ablated pattern is designed for heating the windshield in front of the camera for defogging/deicing.

11. Embodiment eleven comprises a panoramic roof with a low-emissivity solar control coating on surface four. The coating has an SiOxNy dielectric Na-blocking layer having an index of refraction of 2.00 and a functional layer comprising indium-tin-oxide (ITO) layer with sheet resistance of 110 ohms/sq deposited over the SiOxNy dielectric layer and facing towards the vehicle interior. The ablated pattern is defined to form segments in the ITO coating for touch-sensitive applications. Each segment is electrically connected to a controller to register touch events.