RU2772369C1 - Article with a coating including a silver-containing layer after ultrafast laser treatment in a thin-film low-emittance coating, and (or) method for manufacture thereof - Google Patents

Abstract

FIELD: glass.

SUBSTANCE: group of inventions relates to an article in the form of glass with a low-emittance coating, an insulating glass unit containing said article with coating, and an apparatus for manufacturing said article. Article in the form of coated glass comprises a glass substrate and a spray-applied low-emittance coating on the basis of the glass substrate. The low-emittance coating comprises at least one silver-based layer on top of and in contact with a zinc oxide-containing layer. The low-emittance coating is impacted using subpicosecond laser pulses with an energy density of at least 50 kW/cm² in order to reduce the amount of vacancies in the silver-based layer or layers and reduce the amount of twin grain boundaries between the silver-based layer and the adjacent lower zinc oxide-containing layer. The silver-based layer has an Ag(111) particle size of at least 13.2 nm after laser impact.

EFFECT: coating with improved optical characteristics, exhibiting greater strength and corrosion resistance.

7 cl, 9 dwg

Description

FIELD OF TECHNOLOGY

[0001] Certain embodiments of this invention relate to coated articles, including substrates (eg, glass substrates) that form the basis for low emissivity coatings, and/or methods for making them. More specifically, certain embodiments relate to ultrafast laser processing of low emissivity silver coatings, products with such coatings, and/or related methods.

BACKGROUND AND SUMMARY OF THE INVENTION

[0002] Coated articles are known in the art. Coated products are for example used in the manufacture of windows, in particular insulating glass units, laminated products, automotive glass and/or other similar products.

[0003] In certain situations, coated product designers often seek a combination of preferred visible transmittance, preferred color values, high selectivity (LSG, which is equal to the visible transmittance (T _vis ) divided by the gain of the solar heat (Solar Heat Gain Coefficient, SHGC)), low emissivity (or low emissivity), low solar heat gain coefficient (SHGC) and low sheet resistance (R _S ). High visible transmittance, for example, allows coated products to show benefits in certain window applications. The characteristics of low emissivity, low solar heat gain (SHGC), high selectivity (LSG), and low sheet resistance, for example, allow such coated articles to block a significant amount of infrared (IR) radiation, preventing it from penetrating the article. For example, by reflecting IR radiation, you can reduce the degree of unwanted heating of a car or the interior of a building.

[0004] Low emissivity coatings typically include one or more thin film layers containing infrared reflective materials, such as silver, that are sandwiched between dielectric layers. Information about one-, two-, three- and even four-layer silver coatings has been disclosed. Low emissivity coatings are beneficial in industrial and residential windows, glass roofs and other applications and are used in monolithic and laminated products, insulating glass units and other products. However, the availability of coatings consisting of very thin layers based on silver and having a low surface resistance of the layer, in many respects, is contrary to the requirements that require careful optimization of build-up and other processes. It will be appreciated by those skilled in the art that it is often considered impracticable to carry out such an optimization on platforms of multiple coaters intended for commercial applications. Therefore, it is preferable to search for ways of subsequent technological processing of multilayer coatings containing thin silver-based films in order to optimize the surface resistance of the layer, emissivity, thickness of the silver layer, deposition rate, etc.

[0005] Numerous attempts have been made to improve the quality of such coatings. For example, attempts have been made to improve the quality of the silver-based layer or other IR reflective layer, in particular to improve the values of LSG, SHGC, emissivity and/or other values. Although low emissivity coatings in their current form are useful in a wide range of applications, it is preferable to improve the quality of thin silver films deposited by sputtering, especially where such films are formed at very high deposition rates. The nature of the deposition is such that the films often have a high concentration of various structural defects (for example, vacancies, Frenkel defects, dislocations in the crystal lattice, etc.). By their nature, these defects may be surface defects and/or volume defects, sometimes they may not allow thin films to show the necessary volumetric characteristics. From the point of view of the energy landscape of films, these defects can be contained in deep energy wells.

[0006] In this regard, sputter deposition usually involves supercooling the deposited atoms, since the deposition temperature is often well below the melting point. In general, sputter-deposited films have a significantly higher concentration of vacancies in the crystal lattice than would be expected at the thermal equilibrium values for a given deposition temperature. Heating reduces the number of vacancies, allowing them to migrate to the film surface, for example, due to grain boundaries, dislocations, etc.

[0007] Traditional heating involves the use of time periods longer than milliseconds. In practice, during heat treatment, it is not uncommon to use time intervals of 1–10 minutes or more. Under such heating regimes, both electrons and phonons are heated simultaneously. Unfortunately, however, standard heating times are too long, which often actually allows heat to diffuse more into the substrate or surrounding media than into the metal films. Temperature gradients are created, and they are much higher than the mean free path for heat transfer fluids. Contaminant atoms can easily diffuse into the metal system after recrystallization. And although the kinetic energy is always close to equilibrium, defects are difficult to anneal at commonly used temperatures, which, in any case, are often limited by the choice of substrate.

[0008] Certain implementation examples address these and/or other problems. In particular, certain embodiments of the present invention relate to methods for improving the quality of infrared reflective layers in low emissivity coatings and/or other coatings. That is, certain embodiments reduce defects and/or promote recrystallization of silver-based layers in low emissivity coatings. In certain embodiments, this is achieved through ultra-fast melting, which is achieved using picosecond and sub-picosecond lasers. Certain embodiments advantageously improve layer sheet resistance, emissivity, visible transmittance, and the like.

[0009] In certain embodiments, a method for making a coated article is provided. A low emissivity coating is formed on a substrate (e.g., borosilicate or soda-lime glass), wherein the low emissivity coating comprises at least one silver-based sputter-deposited layer, and each of said silver-based layers is sandwiched between one or more dielectric layers. The coating with a low emissivity is exposed to laser pulses with a duration of up to 10 ^-12 seconds, a wavelength of 355–500 nm and an energy density of more than 30 kW/cm ² . Laser processing is carried out in such a way as to prevent the temperature increase of the coating with a low emissivity above 300 degrees C while reducing: a) the number of grain boundaries in relation to each specified silver-based layer and the number of vacancies in the crystal lattice present in each specified layer; b) the refractive index of each said silver-based layer; and c) the emissivity of the low emissivity coating compared to its shape immediately after deposition.

[0010] In other embodiments, one, two, three or more non-silver layers may be used.

[0011] According to certain embodiments, each of said silver-based layers can be applied over and in contact with a corresponding metal oxide layer, in particular zinc oxide (eg, a zinc-tin oxide layer). Each layer containing metal oxide (eg, each layer containing zinc oxide or other similar material) may be substantially crystalline prior to laser processing.

[0012] In accordance with certain embodiments, the standard emissivity can be improved by at least 9% in the low emissivity coating compared to the state immediately after deposition.

[0013] In accordance with certain embodiments, the laser processing may be carried out in such a way as to promote at least a certain degree of recrystallization of each of these layers containing silver.

[0014] According to certain embodiments, laser processing may be athermal to at least the silver-based layer or layers.

[0015] In certain embodiments, a method for manufacturing a coated article is provided. The method involves providing a low emissivity coating on a glass substrate, wherein the low emissivity coating comprises at least one silver-based sputter-deposited layer, and each of said silver-based layers is sandwiched between one or more dielectric layers. The low emissivity coating is exposed to laser pulses with a duration of no more than 10 ^-12 seconds and an energy density of at least 50 kW / cm ² , laser processing is carried out in such a way as to prevent the temperature of the low emissivity coating from rising above 300 degrees C, while also observed: (a) a decrease in the number of vacancies in each specified layer based on silver; (b) reducing the refractive index of each of said silver-based layers; (c) improving the visible transmittance for the low emissivity coating; (d) reducing the emissivity of the low emissivity coating compared to the form immediately after deposition to a level sufficient to break the relationship between the emissivity and the reduction in sheet resistance of the layer. In certain embodiments, the electrical conductivity (eg sheet resistance of the layer) can also be improved.

[0016] In certain embodiments, a coated article is provided. The coated article includes a glass substrate; and the low emissivity sputter coating is based on a glass substrate, the low emissivity coating having at least one silver based layer over and in contact with the zinc oxide containing layer. The low emissivity coating is treated using sub-picosecond laser pulses that have an energy density of at least 50 kW/cm ² in order to remove vacancies in the silver based layer or layers and twin grain boundaries between the silver based layer or layers and the adjacent bottom layer or layers containing zinc oxide. After laser treatment, the low emissivity coating has an improved emissivity below 0.02 (for example, each said silver-based layer is less than 25 nm, preferably less than 20 nm).

[0017] Features, aspects, advantages, and implementations described herein may be combined in further implementations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] These and other characteristics and advantages can be better and more fully understood with reference to the following detailed description of exemplary embodiments taken in conjunction with the drawings, among which:

[0019] FIGURE 1 is a schematic representation that demonstrates the melting process for some embodiments;

[0020] FIGURE 2 is an example of a two-layer low emissivity silver coating that was used in connection with the first set of samples;

[0021] FIGURES 3A-3B are graphs showing transmittance versus wavelength before and after laser treatment for low emissivity coated transparent glass samples, which are described in connection with FIG. 2;

[0022] FIGURES 4A-4B are graphs showing glass-side reflectance versus wavelength before and after laser treatment for low emissivity coated transparent glass samples, which are described in connection with FIG. 2;

[0023] FIGURES 5A-5B are graphs showing the film-side reflectance versus wavelength before and after laser treatment for low emissivity coated transparent glass samples, which are described in connection with Figs. 2;

[0024] FIGURE 6 is an example of a single layer low emissivity silver coating that was used in connection with the second set of samples;

[0025] FIGURE 7 is a graph showing transmittance versus wavelength for five samples from the second set of samples along with the transmittance curve for the original sample in the immediately after coating state;

[0026] FIGURE 8 is an enlarged view of a portion of the graph of FIG. 7 ; and

[0027] FIGURE 9 is an example of a single layer low emissivity silver coating that was used in connection with the third set of samples.

DETAILED DESCRIPTION

[0028] Certain embodiments of this invention relate to ultrafast laser processing of low emissivity silver coatings, products with such coatings, and/or related methods. Ultra-fast modification of thin films involves the use of laser pulses of picosecond or sub-picosecond (for example, 10 ^-12 seconds or less duration, more preferably on the order of units, tens or hundreds of femtoseconds (and possibly less)) duration, for example, to improve the performance of a multilayer coating, in particular if such multilayer coatings include one or more silver-based layers. Laser modification is taking place and is likely to cause at least partial crystallization or recrystallization of the silver or silver-containing layers. However, perhaps a more important factor in improving the quality of silver-based layers is the reorientation of the grains and the impact on the grain boundaries. In this regard, the silver-based layers have an improved texture and are able to become denser and more voluminous. In addition, the quality of the interaction surface between the silver-based layer and at least the underlying dielectric layer and/or the interaction surface between the silver-based layer and the cover layer is improved. For example, if a silver content layer is formed directly on top of and in contact with a zinc oxide layer (e.g., a zinc-tin oxide layer), the quality of the interaction surface is improved because the laser modification helps to reduce twin grain boundaries. The same or something similar may be true of the interaction between, for example, a silver content layer that is formed under and in direct contact with a Ni, Cr and/or Ti layer (e.g., a NiCrOx layer) . Melting is considered to be initiated in the upper and/or lower contact zone (for example, in the contact zone between the silver-based layer and the NiCrOx layer and/or in the interaction zone between the silver-based layer and the zinc oxide layer) at temperature, which is much lower than the melting point of bulk silver, in turn, contributes to an increase in the roughness of the contact surface. Because the treated silver-based layer is bulkier and contains fewer defects (fewer vacancies and fewer grain boundaries) and fewer twinned grain boundaries, the multilayer coating as a whole exhibits improved thermal conductivity (and lower layer sheet resistance), emissivity (both hemispherical, and normal), the ability to transmit in the visible range of the spectrum and the ability to reflect infrared radiation. In a multilayer coating, the refractive index and the k value of the silver-based layer or layers are lowered, thereby improving the optical performance of the coating. In addition, such coatings may become stronger and/or more resistant to corrosion, for example, because the measurement of a multilayer coating after laser processing indicated the presence of an overall compressive stress (rather than tensile stress).

[0029] In traditional coatings, there is a relationship between the surface resistance of the layer and the emissivity. In general, there is a direct correlation between them, which manifests itself in the fact that the decrease in the surface resistance of the layer is accompanied by the expected corresponding decrease in the emissivity. However, in some specific embodiments, femtolasers or similar devices are used, which adversely affects the mobility of electrons after processing. Certain implementations provide a reduction in emissivity in this way to below 0.02 (and sometimes below 0.015), while there is a break in this relationship. Therefore, laser processing in certain embodiments allows to reduce the conductivity while reducing the normal and hemispherical emissivity in a way that does not correspond to the expected changes.

[0030] Surprisingly and unexpectedly, a multi-layer coating can be improved without a significant amount of crystallization (or recrystallization) of silver. This is contrary to the principle by which heat treatment normally works, and also contradicts the remelting (ablation) that often occurs when lasers are used on metals. In certain embodiments, ultrafast laser processing delivers energy using laser pulses. Any "heating" within the framework of this method is carried out on such time scales that atoms cannot diffuse into the coating. Instead, laser processing simply excites electrons, which have low heat capacity because they have almost no mass. Therefore, general physical temperature measurements do not show such high values. Data collected using a thermocouple and a thermal imager showed that there was no perceptible rise in the temperature of the coating applied to the samples, which is contrary to what is expected in traditional heat treatment, as well as in many other types of laser processing. For example, continuous wave (CW) laser processing does not have this property. Moreover, although a reduction in the surface resistance of the layer may be observed when using a CW laser, polished marks can be seen in the silver layers. In certain implementation examples, it is possible to carry out ultrafast laser modification of a multilayer coating while excluding an increase in the temperature of the multilayer coating above 300 degrees C (for example, according to the results of measuring its surface temperature). In certain embodiments, ultrafast laser modification of a multilayer coating is "athermal" with respect to at least the silver layer or layers present therein. In some instances, the method may be "athermal" to the multilayer coating as a whole. Thus, in certain embodiments, the temperature of the multilayer coating does not rise above 300 degrees C, and preferably rises no more than 50 degrees C, more preferably no more than 30 degrees C, and sometimes no more than 5-10 degrees C. Therefore, certain embodiments allow achieving high levels of conductivity and emissivity, surprisingly and unexpectedly, without significant temperature rise and necessarily significant crystallization (or recrystallization). Certain implementations do not involve ablation, although some polished markings may be observed in some cases.

[0031] Without intending to introduce theoretical limitations, a possible explanation of certain mechanisms by which certain implementations may operate can be provided. When using ultrafast laser exposure, there is a temperature spike caused by the "heating" of electrons to temperatures that are multiples of 10,000 K. When the laser impacts the coating, this temperature spike causes a homogeneous melting with respect to the silver-based layer or layers in the first few picoseconds. More specifically, laser pulses excite conductive electrons (for example, in combination with a high-density electron "gas"), and the bound electrons are also excited. This hot electron gas interacts with the ionic lattice (for example, in combination with a cloud of phonons). The phonon cloud has both sonic and optical branches, and optical phonons are favorably localized. Therefore, laser pulses are capable of changing the state of aggregation of (nano)crystalline and (or) other silver to liquid within about 1 picosecond. The melting front extends beyond the absorption depth, and the resulting temperature gradient is less than the mean free path.

[0032] Ultra-rapid heating can deliver energy of the required density per unit area (eg, 0.1 to 0.5 J/cm ² ) to excite high-density electrons, resulting in rapid heating and subsequent cooling. The creation of a high concentration of vacancies (nc) has a significant effect on the phase transition. If a high value is present, recrystallization may occur to some extent, but probably to a greater extent, grain boundary migration is accelerated, larger grains are formed for the first time or re-formed, while improving the bulk properties of the silver. The advantage of this approach is that it does not lead to a noticeable increase in the temperature of the coating, and, as discussed above, it is athermal at least with respect to silver. The result is a very low surface energy and strain energy that is introduced into the system. It is believed that an energy density of at least 30 kW/cm ² is needed to create certain embodiments, for example, with the duration described here.

[0033] Fig. 1 is a schematic representation that demonstrates the melting process for some embodiments. As shown in Fig. 1, the pulsed beam 102 penetrates the upper insulator 104 for an absorption path length L (which is equivalent to the laser wavelength in certain embodiments) and into the silver-based layer 106. The absorption path length L should preferably not span the lower insulator 108. As will be seen in example of the multilayer coatings detailed below, the lower insulator 108 may be a zinc oxide layer (e.g., a zinc-tin oxide layer), and the upper insulator 104 may be a Ni, Cr, and/or Ti layer (e.g., , layer containing NiCrOx). In certain embodiments, lower insulator 108 may be crystalline prior to laser beam treatment.

[0034] Across the width of the pulsed beam 102, the solid portion 106a liquefies, creating a liquid portion 106b. The melting front 106c gradually extends to the depth of the silver-based layer 106 (for example, during subsequent scanning by changing the length of the absorption path L, etc.). The onset of melting predominantly occurs at temperatures well below the melting point of bulk silver. In the lower insulator 108 acoustic phonons are coupled. As noted above, the process is inherently athermal, since the excitation is very fast and the electrons transfer a large amount of energy with a very small mass. It is also valuable that in this process there is no deliberate thermal heating of the silver-based layer or any other layer in the multilayer coating, and there is no absorbing layer.

[0035] The advantage is that the duration of the laser pulse is less than the binding time of e-phonons. If this were not the case, the laser would provide plasma binding instead of initiating the excitation of electrons inside the metal film. Therefore, in certain embodiments, laser processing of thin films in a pulsed mode is used in a very short time. This provides lower energy loss and reduces the risk of substrate damage.

[0036] Ultra-thin silver-based film layers are melted by exposure to ultra-fast laser pulses at temperatures well below 970 degrees C for silver, as discussed above. In thick films (for example, bulk systems), the ratio of surface area to volume is extremely small, and surface curvature can be neglected. Thus, the surface effect of the melting temperature can be neglected. However, in the case of a nanometric thin film composed of Ag and containing nanosized grains (for example, 3–5 nm in size), for which the surface area to volume ratio is large and the surface curvature is high, the melting temperature depends on the size. These features can be partially explained by thermodynamic theory and experimentally confirmed by electron diffraction, x-ray diffraction, differential scanning calorimetry and transmission electron microscopy. However, an additional effect of the kinetic interaction of fast laser pulses with the contact surface of Ag and the dielectric is a significant decrease in the melting temperature of the nanothick silver film to 125 degrees C. Since the pressure inside the film is much higher than the vapor pressure of Ag, evaporation of the films is not expected. Instead, the initial initiation of melting is followed by rapid quenching and annealing of defects on the contact surface. Generally:

Tm, f _f= T ₀ (1 - σSL / (L ₀ <r>)),

where Tm is the melting point of the film with grain size (e.g., radius) r, T ₀ is the melting point of the bulk silver film, σSL is the solid-to-liquid interfacial transition energy, and L ₀ is the latent heat of fusion of the bulk film. However, there are significant differences between what is predicted by this equation and the experimentally obtained value of Tm, f, even if the vacuum pressure in the environment of thin-film multilayer coatings is taken into account. One possible reason may be a change in the energy of the interfacial transition from a solid to a liquid state due to the effect of curvature or the effect of non-equilibrium. Laser radiation is actually coupled to the Ag (insulator) surface film by excitation of surface plasmons, while the joint oscillations of electrons contribute to the effective absorption of laser photons.

[0037] In connection with certain embodiments, the following laser parameters may be used.

Laser mode. Pulsed, with a width of no more than a few picoseconds, more preferably on the order of units, tens or hundreds of femtoseconds (but possibly lower). In some embodiments, the duration in the pulse mode may be no more than 10 ^-12 seconds, more preferably on the order of units, tens or hundreds of femtoseconds. A duration of less than a few picoseconds (eg, less than 9 picoseconds, more preferably less than 5 picoseconds, and even more preferably less than or equal to 1-3 picoseconds) is preferred. The duration for one example is 100-500 femtoseconds (more preferably 100-300 femtoseconds and 100-200 femtoseconds as an example). For durations less than 1 femtosecond, the energy density is generally too low to achieve the results described here, for example, by not reaching the obvious threshold of 30 kW/cm ² .

Laser type. Excimer laser (for example, operating in the linear frequency modulation mode). In some cases, Ti-sapphire lasers can also be used in combination with SHG (second harmonic generation).

Power density. Not less than 30 kW/cm ² , more preferably not less than 50 kW/cm ² . The power density is preferably chosen to prevent damage and scarring of the film. At a value of 50 kW/cm ² a crystallization of over 50% was achieved.

Wavelength. Typically, a wavelength of 355-500 nm can be used. The samples were made using an excimer laser at a wavelength of 355 nm. Samples were also fabricated using an SHG laser (Second Harmonic Generation Laser) at a wavelength of 400 nm. In some cases, a gallium nitride (GaN) laser at 405 nm can be used.

Beam profile. Homogeneous flat top beam (Homogeneous Flat Top, HFT). The advantage of the HFT profile beam (compared to, for example, the Gaussian beam profile) was the absence of micro-scars and the observed increase in corrosion resistance.

Beam size. Preferably < 500 microns, in some embodiments a more highly directional beam may be used.

Proposed takeover mechanism. Surface and bulk Ag plasmons are mediated (compared to, for example, using a temperature profile with a separate absorbing layer in a multilayer coating). This approach works successfully for multi-layer coatings with one, two and three layers of silver. Certain embodiments have the advantage of not having a separate absorbent layer, instead they are athermal as described above.

Optical devices of the beam. Potentially galvanic based, which implies an extremely high scanning speed of a moving target. In some implementations, a Shafter-Kirchhoff line scan generator may be used.

Range of laser radiation density. 0.5 to 5 J/cm ² , more preferably 0.5 to 3 J/cm ² and possibly 0.1 to 0.6 J/cm ² .

Pulse repetition rate. 1-100 kHz

Stability in the interval between pulses. 0.5-1% rms

long term displacement. 0.1-0.5%) rms

Environmental conditions for laser processing. Laser processing can be carried out in atmospheric air, in nitrogen, in full or partial vacuum, etc.

[0038] Based on the experimental data obtained to date, it is believed that the methods described here can be used to partially or completely improve the characteristics of the surface resistance of the layer, emissivity (both normal and hemispherical), transmittance and refractive index (or refractive index in the case when multilayer coatings include several silver-based layers). For example, it is believed that the sheet resistance of the layer can be improved (eg, reduced) by at least 9%, more preferably by at least 11%, more preferably by at least 15%, and possibly by 15-20% or more; normal and hemispherical emissivity can be improved (eg reduced) by at least 9%, more preferably by at least 11%, more preferably by at least 15%, and possibly by 15-20% or more; the normal emissivity may reach a level which is preferably below 0.02, more preferably below 0.015; the refractive index (or refractive indices) of the silver-based layer or layers at 550 nm can be improved (eg, reduced) by at least 10%, more preferably by at least 15%, and possibly by 20-25% or more; the visible transmittance (TY) can be improved (eg, increased) by at least 0.25%, more preferably by at least 0.5%, and possibly by 0.75-1.5% or higher. In some instances, it may be desirable to have as low a gain in visible transmittance as possible, which in some cases may be achievable. In general, by changing several parameters, such as the wavelength of the pulse duration, active cycle time and energy density, as well as the crystallite size of the initial film and seed layer, it is possible to tune the time-constant values of tau and resistance, which, in turn, encode the fundamental properties of thin and thick silver films. As one example, an energy density per unit area in the range of 0.5 to 5 J/cm ² , more preferably 0.5 to 2 J/cm ² , for a pulse duration of 100-200 femtoseconds at a wavelength of 450 nm can be used .

SAMPLE PACK 1

[0039] Fig. 2 is an example of a two-layer low emissivity silver coating that was used in connection with the first set of samples. The coating shown in Fig. 2 was formed on 3.2mm clear glass and 0.7mm Eagle glass, both substrate materials are commercially available. As is known, the former is soda-lime glass and the latter is borosilicate glass. The nominal physical thickness of the coating used in this sample was determined as follows:

Material/Layer Preferred thickness (nm) More preferred thickness (nm) Sample thickness (nm) Si ₃ N ₄ [212] 15-30 17–25 22.0 ZnSnOx (50/50) [210b] 5–18 7–15 10.5 NiCrOx[208b] 1–10 2–8 3.5 Ag[204b] 5–18 7–16 13.6 ZnSnOx (90/10) [206b] 15–25 18–23 19.9 ZnSnOx (50/50) [210a] 50–90 55–80 69.00 NiCrOx[208a] 1–10 2–8 3.5 Ag[204a] 2–12 4–10 7.5 ZnSnOx (90/10) [206a] 30–50 35–45 39.4 GLASS [202] Not applicable Not applicable Not applicable

[0040] It is noted that the area of laser irradiation is more visible on clear glass than on Eagle glass. Rice. 3A-3B are graphs showing transmittance versus wavelength before and after laser treatment for Clear Glass and Eagle Glass samples, respectively; Rice. 4A-4B are graphs plotting glass-side reflectance versus wavelength before and after laser treatment for these Clear Glass and Eagle Glass samples, respectively; a Fig. 5A-5B are graphs showing film-side reflectance versus wavelength before and after laser treatment for these clear glass and Eagle glass samples, respectively. The table below summarizes this transmittance, reflectance, and color change information for the samples, as well as the layer sheet resistance information:

Clear glass Eagle glass State After coating After laser treatment After coating After laser treatment Surface resistance layer 2.15 1.9 2.22 2.13 Turbidity 0.19 0.12 0.21 0.18 Y[T] 74.11 76.92 74.63 75.72 L*[T] 88.98 90.28 89.22 89.73 a* [T] -4.4 -4.14 -3.87 -3.8 b* [T] 4.9 5.39 5.2 5.58 Y[Rf] 10.2 10.33 9.81 9.72 L* [Rf] 38.2 38.44 37.51 37.34 a*[Rf] 0.04 0.12 1.45 1.61 b* [Rf] -5.06 -4.64 -5.1 -5.14 Y[Rg] 10.16 10.2 9.85 10.02 L* [Rg] 38.13 38.19 37.58 37.88 a*[Rg] -0.55 -0.23 -0.19 -0.21 b* [Rg] -9.81 -8.44 -9.33 -8.35 ∆E* [T] 1.41 0.64 ∆E* [Rf] 0.57 0.4 ∆E* [Rg] 0.56 0.43

[0041] It can be seen that the transmittance increased and the surface resistance of the layer decreased. The coloration of the transmission type also remained largely unchanged, with the color coordinates a and b changing only moderately with respect to the reflectance on the film side and on the glass side.

[0042] The following table summarizes information about the change in texture for samples obtained by measuring X-ray diffraction (X-ray Diffraction, XRD). Eagle glass texture change (after laser treatment) showed a 45% improvement in quality, clear glass texture change (after laser treatment) showed a 57% improvement in quality. Compared to the condition of silver on clear glass immediately after application, the condition of silver on Eagle glass immediately after application is a relatively poorer texture, which may help explain the lower texture change of the coating on Eagle glass compared to the coating on clear glass.

Ag(111) Ag(111) Ag(111) Ag(111) ZnO(002) Max. amount Angle at max. Full width at half maximum (FHWM) Particle size [nm] Max. amount Eagle glass after laser processing 801 38.26 0.727 13.9 228 Eagle glass immediately after coating 554 38.16 0.784 12.9 240 Clear glass after laser processing 2603 38.28 0.766 13.2 996 Clear glass immediately after coating 1658 38.18 0.844 12 1052

[0043] The samples were measured to determine the refractive indices (at 550 nm) of the upper and lower layers based on silver before and after laser processing. The refractive indexes of the silver-based upper and lower layers in the as-deposited state for the clear glass samples were 0.11 and 0.16, respectively, after laser processing, these values decreased to 0.08 and 0.10, respectively. The surface roughness before laser treatment was 5.84 nm, after laser treatment this value increased to 5.94 nm.

[0044] The refractive indexes of the top and bottom silver-based layers in the as-deposited state for Eagles glass samples were 0.14 and 0.20, respectively, after laser processing, these values decreased to 0.11 and 0.19, respectively. The surface roughness before laser treatment was 5.70 nm, after laser treatment this value increased to 5.67 nm.

[0045] In both the clear glass and Eagle glass samples, the layer thickness remained substantially the same after laser processing. This means that none of the layers showed a change in thickness of more than 0.4 nm, and most of the layers showed a change in thickness of more than 0.3 nm.

[0046] Considering these data, it can be assumed that the quality of the upper silver layer will improve more than the quality of the lower silver layer in the low emissivity double-layer silver plating. It can also be assumed that in a three-layer low emissivity silver coating, changes in the upper silver layer will be the most significant compared to the underlying silver layers, and thus make the largest contribution to the change in the overall emissivity of the coating.

SAMPLE PACK 2

[0047] Fig. 6 is an example of a single layer low emissivity silver coating that was used in connection with the first set of samples. The coating shown in Fig. 6 was formed on transparent glass with a thickness of 3.8 nm. The nominal physical thickness of the coating used in this sample was determined as follows:

Material/Layer Preferred thickness (nm) More preferred thickness (nm) Sample thickness (nm) ZrOx[324] 1–15 3–10 3 Si ₃ N ₄ [322] 3–25 5–15 11.1 SnOx[320] 2–10 3–8 5.5 ZnOx[318] 10–25 12–22 17 ZnSnOx[316] 2–12 4–10 6.6 NiCrOx[314] 1–10 2–8 3 Ag[308] 2–15 4–13 8.7 ZnOx[312b] 8–20 10–16 12.3 ZnSnOx[310b] 2–10 3–7 4.1 ZnOx[312a] 2–10 3–8 4.8 ZnSnOx[310a] 2–10 3–8 5.3 TiOx[306] 1–10 2–8 3 ZrSiOxNy [304] 3–15 5–12 7.4 GLASS [302] Not applicable Not applicable Not applicable

[0048] The measurements were carried out on 5 different samples, as well as a sample in its original state immediately after coating. For the first four samples, a laser power of 135 mW was used, and for the fifth sample, a laser power of 130 mW was used. The overlap or line spacing value for Patterns 1-2 and 5 was 0.03 mm, the overlap or line spacing value for Pattern 3 was 0.02 mm, the overlap or line spacing value for Pattern 4 was 0.01 mm. The laser scanning speed was 3 mm/s for sample 2 and 5 mm/s for all other samples.

[0049] Fig. 7 is a graph showing transmittance versus wavelength for five samples from the second set of samples along with the transmittance curve for the original sample in the immediately after coating state. Rice. 8 is an enlarged view of a section of the graph from Fig. 7. The improvement in transmission was achieved by increasing the overlap value (reducing the offset along the slow scan axis), which is most noticeable for the fourth sample. Samples 4-5 were confirmed to have no microscopic damage related to laser processing.

SAMPLE PACK 3

[0050] Several additional samples of low emissivity coated products with a single silver layer were processed using a standard set of parameters. These parameters include a power of 150 mW, a scanning speed of 5 mm/s, an overlap or line spacing of 0.035 mm, the laser operates at a wavelength of 532 nm at a repetition rate of 100 kHz and a beam diameter of 1 mm. In general, the testing used a processing power of 0.1-5.0 W and a value of overlap or line spacing of 0.04-0.025 mm, the use of these values was considered appropriate for various implementations.

[0051] Among the heat-treated multilayer coatings, there was one sample corresponding to that shown in Fig. 6 with the layer thickness shown above, as well as two-layer coatings having the configuration shown in Fig. 9. The coating shown in Fig. 9 was formed on 3.8 mm thick transparent glass. The nominal physical thickness of the coating used in these two specimens was determined as follows:

Material/Layer Preferred thickness (nm) More preferred thickness (nm) Sample thickness (nm) ZrOx[922] 1–15 3–10 3.3 Si ₃ N ₄ [920] 1–30 10–25 18.9 and 14.6 ZnOx[918] 10–25 12–23 17.9 ZnSnOx[916] 2–12 4–10 6.4 NiCrOx[914] 1–10 2–8 3 Ag[912] 5–30 8–25 19.6 and 11.5 ZnOx[910] 3–15 5–13 7.3 and 8.8 ZnSnOx[908] 1–10 2–5 2.2 and 3.1 TiOx[906] 1–10 3–9 3.6 ZrSiOxNy [904] 3–15 5–12 7.4 GLASS [902] Not applicable Not applicable Not applicable

[0052] The following table contains data indicating how the characteristics of these coatings improved after laser processing.

SR improvement En improvement TY boost Sample from Fig. 6 10.6% 12.7% 0.41% Sample from Fig. 9 (thin silver layer) 13.7% 9.3% 0.88% Sample from Fig. 9 (thick silver layer) 21.2% 15.8% 1.19%

[0053] The embodiments described herein can be used in a wide variety of applications including, for example, interior and exterior windows for industrial and/or residential buildings, glass roofs, doors, merchandising products (e.g., doors, and ( or) walls of refrigerators and freezers), windows for cars, etc.

[0054] The methods described here have been discussed in connection with certain examples of low emissivity coatings. However, it is noted that various low emissivity coatings can be improved by applying the laser processing techniques described herein. Such low emissivity coatings may contain one, two, three or more Ag-based layers, they may or may not contain underlying layers containing ZnOx, ZnSnOx, etc., they may or may not contain silver-based coating layers with content of Ni, Cr, Ti and/or similar materials (e.g. NiCrOx), etc. For example, although a layer containing zinc oxide (e.g. zinc-tin oxide) may be used directly under and in contact with the silver-based layer or layers , it would be valuable if metal oxide layers and/or other layers could be used in various embodiments. In some embodiments, these metal oxide layers and/or other layers may be substantially crystalline prior to laser processing.

[0055] Although certain embodiments have been described in connection with coated articles that comprise a single glass substrate as the basis for the coating, it would be appreciated if the techniques described herein could be applied in connection with the fabrication of insulating glass units comprising two substantially parallel substrates separated from each other by a system of spacer elements that allow you to set the air gap between them. Low emissivity coatings can be applied to any one or more of the major surfaces of such articles (eg, surfaces 2 and/or 3). This air gap can be filled with an inert gas such as Ar, Kr, Xe or others, with or without oxygen. It would also be valuable if the methods described here could be applied to so-called triple glazing units. In such blocks, the first, second and third actually parallel substrates are separated by the first and second systems of spacers, and coatings with low emissivity and (or) antireflection coatings (Antireflection, AR) can be used in the vicinity of one or more internal surfaces of the innermost and most outer substrate and/or with one or both surfaces of the middle substrate. Low emissivity coatings can be applied to one or more primary surfaces (typically the primary internal surfaces). Similarly, the techniques described herein may be used in connection with Vacuum Insulating Glass (VIG) units in which a first and second substantially parallel substrate is maintained in this configuration in connection with the use of a plurality of spacers or studs and a peripheral edge seal. . The peripheral edge seal in such cases is usually formed from a frit and hermetically seals the gap or cavity in the vacuum insulating glass unit. Inside the gap or cavity, the pressure is maintained below atmospheric pressure. As described above in the insulating glass unit example, low emissivity coatings can be applied to any one or more major surfaces of such articles (eg, surfaces 2 and/or 3). Moreover, the manufacture of laminated products can also benefit from the use of the methods disclosed herein.

[0056] It will be appreciated that laser processing may be performed on the coated side or the uncoated side on the substrate that is the base for the coating. Thus, laser processing can be carried out on an insulating glass unit, a vacuum insulating glass unit or a laminated product after assembly and (or) on their auxiliary units (for example, before attaching the substrates of an insulating glass unit to each other using a system of spacers, before compacting the substrates block of an insulating glass unit to each other using a frit and (or) pumping air out of the cavity, before laminating the substrate with something else, etc.).

[0057] The terms "heat treatment" and "heat treatment" as used herein means heating an article to a temperature sufficient to provide thermal tempering and/or thermal tempering of an article that contains glass. This definition includes, for example, heating the coated article in an oven or oven at a temperature of at least 550 degrees C, more preferably at least 580 degrees C, more preferably at least 600 degrees C, more preferably at least 620 degrees C and most preferably at least 650 degrees C for a sufficient period of time for thermal tempering and/or thermal hardening of the product. This may take at least two minutes, or up to 10 minutes in some implementations. These processes are adapted to use different times and/or temperatures.

[0058] When used herein, the terms "on", "based on" and the like should not be interpreted in the sense that two elements are in close proximity to each other, unless this is clearly indicated in an explicit form. In other words, the first layer can be said to be "on" or "under" the second layer, even if there are one or more layers in between.

[0059] In certain embodiments, a method for making a coated article is provided. A low emissivity coating is formed on the substrate, wherein the low emissivity coating comprises at least one sputter-deposited silver-based layer, and each of said silver-based layers is sandwiched between one or more dielectric layers. The coating with a low emissivity is exposed to laser pulses with a duration of no more than 10–12 seconds, with a wavelength of 355–500 nm and an energy density of more than 30 kW / cm ² , laser processing is carried out in such a way as to prevent an increase in the temperature of the coating with a low emissivity above 300 degrees C while reducing: a) the grain boundaries in relation to each specified layer based on silver and the number of vacancies present in it in the crystal lattice; b) the refractive index of each said silver-based layer; and c) the emissivity of the low emissivity coating compared to its shape immediately after deposition.

[0060] In addition to the characteristics described in the preceding paragraph, in certain embodiments, the substrate may be made of borosilicate glass or soda-lime glass.

[0061] In addition to the characteristics described in either of the two preceding paragraphs, in certain embodiments, each of these silver-based layers can be deposited on and in contact with a corresponding layer containing zinc oxide.

[0062] In addition to the characteristics described in the preceding paragraph, in certain embodiments, each specified layer containing zinc oxide may be crystalline prior to laser processing.

[0063] In addition to the characteristics described in any of the preceding four claims, in certain embodiments, the low emissivity coating may comprise first and second silver-based layers.

[0064] In addition to the characteristics described in any of the five preceding claims, in certain embodiments, the low emissivity coating may include at least three silver-based layers.

[0065] In addition to the characteristics described in any of the preceding six claims, in certain embodiments, the low emissivity coating may include multiple silver-based layers, and laser processing may be performed such that the texture of the uppermost silver-based layer is changed. stronger than the texture of the underlying silver-based layers.

[0066] In addition to the characteristics described in any of the preceding seven claims, in certain embodiments, laser pulses may have an energy density of at least 50 kW/cm ² and/or a duration on the order of units, tens, or hundreds of femtoseconds.

[0067] In addition to the characteristics described in any of the eight preceding paragraphs, in certain embodiments, the low emissivity coating may be heat treated after the laser treatment.

[0068] In addition to the characteristics described in any of the nine preceding paragraphs, in certain embodiments, laser processing can be performed inline simultaneously with the formation of a low emissivity coating.

[0069] In addition to the characteristics described in any of the 10 preceding paragraphs, in certain embodiments, laser processing can be performed from the side of the substrate on which the low emissivity coating is formed.

[0070] In addition to the performance described in any of the 11 preceding claims, in certain embodiments, the standard emissivity of the low emissivity coating can be improved by as much as 9% compared to the state of the low emissivity coating immediately after deposition.

[0071] In addition to the characteristics described in any of the 12 preceding paragraphs, in certain embodiments, laser processing can be carried out in such a way as to promote at least a certain degree of recrystallization of each of these layers containing silver.

[0072] In addition to the characteristics described in any of the 13 preceding paragraphs, in certain embodiments, the laser processing may be athermal with respect to at least the silver-based layer or layers.

[0073] In certain embodiments, a method of manufacturing a coated article is provided that includes a low emissivity coating on a glass substrate, wherein the low emissivity coating comprises at least one silver-based sputter-deposited layer, and each of said layers on The silver base is located between one or more dielectric layers. The low emissivity coating is exposed to laser pulses with a duration of no more than 10–12 seconds and an energy density of at least 50 kW / cm ² , laser processing is carried out in such a way as to prevent the temperature of the low emissivity coating from rising above 300 degrees C, while also: (a) the number of vacancies in each said silver-based layer is reduced; (b) reducing the refractive index of each of said silver-based layers; (c) improving the visible transmittance for the low emissivity coating; (d) reducing the emissivity of the low emissivity coating compared to the form immediately after deposition to a level sufficient to break the relationship between the emissivity and the reduction in sheet resistance of the layer.

[0074] In addition to the characteristics described in the preceding paragraph, in certain embodiments, each of these silver-based layers can be deposited on and in contact with a corresponding layer containing zinc oxide.

[0075] In addition to the characteristics described in either of the two preceding paragraphs, in certain embodiments, laser pulses may have a duration on the order of units, tens or hundreds of femtoseconds.

[0076] In addition to the performance described in any of the preceding three claims, in certain embodiments, the standard emissivity of the low emissivity coating can be improved by as much as 9% over the state of the low emissivity coating immediately after deposition.

[0077] In addition to the characteristics described in any of the preceding four paragraphs, in certain embodiments, laser processing may be performed in such a way as to promote at least some degree of recrystallization and/or grain boundary reduction with respect to each of these silver content layers. .

[0078] In addition to the characteristics described in any of the five preceding paragraphs, in certain embodiments, the laser processing may be athermal with respect to at least the silver-based layer or layers.

[0079] In certain embodiments, a coated article is provided that includes: a glass substrate; and the low emissivity sputter coating is based on a glass substrate, the low emissivity coating having at least one silver based layer over and in contact with the zinc oxide containing layer. The low emissivity coating is treated using sub-picosecond laser pulses that have an energy density of at least 50 kW/cm ² in order to remove vacancies in the silver based layer or layers and twin grain boundaries between the silver based layer or layers and the adjacent bottom layer or layers containing zinc oxide. The low emissivity coating after laser processing has an emissivity below 0.02.

[0080] In addition to the characteristics described in any of the preceding paragraphs, in certain embodiments, the coated article may be heat treated while having a low emissivity coating.

[0081] In addition to the characteristics described in either of the two preceding paragraphs, in certain embodiments, the glass substrate may be made of soda-lime glass.

[0082] In addition to the characteristics described in any of the preceding three claims, in certain embodiments, the low emissivity coating may comprise at least the first and second silver-based layers.

[0083] In addition to the characteristics described in any of the four preceding paragraphs, in certain embodiments, the zinc layer or layers may also contain tin.

[0084] In certain embodiments, an insulating glass unit is provided. It may include a coated article from any of the five preceding claims; substrate; and a system of spacers around the peripheral edges of the substrate which help to keep the coated article and the substrate in a substantially parallel and separated state from each other.

[0085] Although the invention has been described on the basis of what is currently considered the most practical and preferred embodiment, it should be understood that the invention should not be limited to the disclosed embodiment and/or methods of deposition, but, on the contrary, is intended to cover various modifications and similar arrangements, which are included in the spirit and scope of the appended claims.

Claims (7)

1. A low emissivity coated glass article comprising a glass substrate and a low emissivity sprayed coating thereon, wherein the low emissivity coating comprises at least one silver-based layer over and in contact with the layer, containing zinc oxide, while the low emissivity coating is exposed using sub-picosecond laser pulses that have an energy density of at least 50 kW/cm ² to reduce the number of vacancies in the silver-based layer or layers and reduce the number of twin grain boundaries between the layer on a silver base and an adjacent bottom layer containing zinc oxide, and wherein the silver based layer after laser exposure has an Ag(111) particle size of at least 13.2 nm as measured by X-ray diffraction (XRD). 2. The product according to claim. 1, which is made with the possibility of heat treatment. 3. An article according to claim 1 or 2, wherein the glass substrate is made of soda-lime glass. 4. The product according to any one of paragraphs. 1-3, wherein the low emissivity coating comprises at least first and second silver based layers. 5. The product according to any one of paragraphs. 1-4, in which the layer or layers containing zinc oxide additionally contain tin. 6. Insulating glass, which includes a product in the form of coated glass with low emissivity according to any one of paragraphs. 1-5, a substrate and a system of spacers around the peripheral edges of the substrate that maintain the coated article and substrate in a parallel, separated state from each other. 7. Apparatus for manufacturing a low emissivity coated glass product comprising a glass substrate and a low emissivity sprayed coating thereon, wherein the low emissivity coating comprises at least one silver-based layer over and in contact with a layer containing zinc oxide, while the device contains a sub-picosecond laser configured to laser impact on a low emissivity coating using sub-picosecond laser pulses that have an energy density of at least 50 kW/cm ² to reduce the number of vacancies in the layer or layers based on silver and reducing the number of twin grain boundaries between the silver based layer and the adjacent bottom layer containing zinc oxide, while the silver based layer after laser exposure has an Ag(111) particle size of at least 13.2 nm when measured by diffraction x-ray radiation (XRD).

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