Description:A MIRROR GLASS DOOR FOR APPLIANCES AND GLASS DOOR APPLICATIONS

FIELD OF INVENTION
The present invention relates to a mirror glass door coating for refrigerator and glass door applications and its method of preparation.

BACKGROUND OF THE INVENTION
The following background discussion includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

Over time, mirrors have gained global recognition for their reflective properties, finding diverse applications in various products such as automotive headlights with rear mirrors, side mirrors, rear view mirrors, dielectric mirrors for displays, projection mirrors, and more. Additionally, the mirror glass door promotes environmental protection through the reutilization of glass in a recyclable manner during production.

The mirror glass door technology offers numerous advantages over traditional plastic, steel, and aluminium doors. With the elimination of numerous manual operations and machine forming of the frame from aluminum roll stock, the mirror glass door significantly reduces the likelihood of wrinkling in the metallized plastic.
The mirror glass doors not only enhance the aesthetic appeal of refrigerator doors but also provide improved functionality, such as easy surface cleaning and resistance to scratches and corrosion. Moreover, the adoption of tempered glass promotes environmental sustainability by facilitating glass recycling during production.
There is a need of a mirror glass door technology which can enhance the aesthetic appeal and durability of refrigerator doors.

There is a further need of a mirror glass door which has improved optical reflectivity, scratch resistance, and corrosion resistance. There is also a need of a method of manufacturing the mirror glass door which has improved optical reflectivity, scratch resistance, and corrosion resistance.

OBJECTIVE OF THE PRESENT INVENTION
An objective of the present invention is to provide a mirror glass door coating for refrigerator and glass door applications and its method of preparation.
Another objective of the present invention is to provide a mirror glass door/s which not only enhance the aesthetic appeal of refrigerator doors but also provide improved functionality, such as easy surface cleaning and resistance to scratches and corrosion.
Another objective of the present invention is to provide a mirror glass door technology which can enhance the aesthetic appeal and durability of refrigerator doors.

Another objective of the present invention is to provide a mirror glass door which has improved optical reflectivity, scratch resistance, and corrosion resistance.

Another objective of the present invention is to provide a method of manufacturing the mirror glass door which has improved optical reflectivity, scratch resistance, and corrosion resistance.

Summary of the Invention:
In an embodiment, the invention provides a mirror glass door coating for refrigerator and glass door, comprising atleast a layer of tempered glass present in the thickness ranging from 2 to 8 mm, a metallic/metal composite layer present in the thickness ranging from about 5 -500 Å, a protective organic paint present in the thickness ranging from 1 – 400 micron.

In another embodiment, the invention provides a method of manufacturing the mirror glass door coating as described above, comprising the steps of:
a) Printing a metallic shade logo on a tempered glass substrate using screen printing technology ;
b) Baking the printed logo at a temperature ranging from 70 to 150 or 80 to 120 or 100 to 120 degrees Celsius for a time interval of 10 to 15 minutes;
c) Depositing a metallic/metal composite layer on the tempered glass substrate using Physical Vapour Deposition (PVD) technique, wherein the metallic/metal composite layer comprises one or more metals selected from the group consisting of Cr, NiCr, Ag, SS, and Al;
d) Applying a protective organic paint layer over the metallic/metal composite layer using screen/spray printing technology;
e) Applying a final top black paint layer over the metallic/metal composite layer using screen/spray printing technology;
f) Applying a surface protection film on the tempered glass substrate to protect the mirror glass door from scratches and fingerprints during transportation.
In an embodiment, the method comprises following steps:
a) Cleaning and applying primer to the surface to be coated;
b) coating the surface by epoxy based or Pu-based organic/ inorganic ink coating, UV-curing ink coating or ceramic-based ink coating or traditional paint coating;
c) baking at the temperature ranging from 70 to 150 or 80 to 120 or 100 to 120 degrees Celsius for a time interval of 10 to 15 minutes;
d) performing metal coating on the surface obtained in step (b) wherein the metal comprises Chromium (Cr), Nickel-Chromium (NiCr), Aluminum (Al), Silver (Ag), Stainless Steel (SS), and Titanium (Ti), wherein the metallic/metal composite layer is deposited using large-area magnetron sputtering in a high vacuum environment at a pressure of 10 x E-6 mbar, at room temperature;
e) coating the surface by the steps selected from Pu-based organic ink coating, UV-curing ink coating or ceramic-based ink coating or traditional paint coating;
f) baking/ curing at a temperature ranging from 70 to 150 or 80 to 120 or 100 to 120 degrees Celsius for a time interval of 10 to 15 minutes;
g) incorporating the float glass into the coated surface, wherein the float glass comprises Clear, Green, Grey, Bronze, Dark Grey, and Blue float glass with varying thicknesses from 2mm to 12mm;
h) applying the Plastic Pressure/Heat-Sensitive Surface Protection Film.

This together with the other aspects of the present invention along with the various features of novelty that characterized the present disclosure is pointed out with particularity in claims annexed hereto and forms a part of the present invention. For better understanding of the present disclosure, its operating advantages, and the specified objective attained by its uses, reference should be made to the accompanying descriptive matter in which there are illustrated exemplary embodiments of the present invention.

DETAILED DESCRIPTION OF DRAWING:
The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and, together with the description, explain the disclosed principles. The reference numbers are used throughout the figures to describe the features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described, by way of example only, and regarding the accompanying figures, in which:

Figure 1 illustrates a perspective view of a refrigerator (1) equipped with a glass door for the freezer section (2) and a glass door for the refrigerator section (3). The innovative feature of this patent is the placement of a decorative mirror (4) on the outer surface of the refrigerator. The strategically positioned mirror (4) enhances the aesthetic appeal of the refrigerator, providing a visually striking and modern addition to any kitchen or living space. The mirror's integration on the appliance's exterior elevates its overall appearance, creating a unique and stylish design that enhances the refrigerator's aesthetics while complementing the surrounding environment.

Figure 2 illustrates an array of advanced coating technologies (4, 5, 6) and protective solutions (8) designed to enhance the aesthetic appeal and durability of various products. The depicted coatings include Pu-based organic ink coating, UV-curing ink coating, ceramic-based ink coating, and paint coating (4, 6), each offering unique visual effects and surface finishes for different applications.
The figure 2 showcases a diverse range of metal coatings (5), such as Chromium (Cr), Nickel-Chromium (NiCr), Aluminum (Al), Silver (Ag), Stainless Steel (SS), and Titanium (Ti), known for their exceptional resilience and decorative properties, making them ideal choices for a wide range of products.
In addition, the figure presents a variety of float glass options (7), including Clear, Green, Grey, Bronze, Dark Grey, and Blue float glass with thicknesses ranging from 2mm to 12mm. These glass types offer designers and manufacturers ample choices to create visually appealing and functional products.
To ensure the preservation of the coated surfaces, the patent figure highlights the Plastic Pressure/Heat-Sensitive Surface Protection Film (8), available in thicknesses from 50 microns to 100 microns. This protective film serves as a reliable safeguard against scratches, abrasion, and potential damage, extending the lifespan and maintaining the appearance of the coated products.
Overall, the figure showcases a comprehensive suite of coating and protection technologies that cater to diverse industries and applications, offering versatility, visual enhancement, and long-lasting performance

Figure 3 presents a concise process flow block diagram outlining the sequential steps involved in the application of the advanced coating and protection technologies described in the patent. The diagram illustrates a streamlined workflow that ensures efficient and effective implementation of these technologies across various products and industries.
The process begins with surface preparation (Step 1), where the substrates to be coated are carefully cleaned and primed to optimize adhesion and coating performance. Next, the selected coating technology is applied based on specific product requirements. The options include Pu-based organic ink coating, UV-curing ink coating, ceramic-based ink coating, and traditional paint coating (Step 2). Following the coating application, the metal coating process (Step 3) is shown, featuring a range of metal options such as Chromium (Cr), Nickel-Chromium (NiCr), Aluminum (Al), Silver (Ag), Stainless Steel (SS), and Titanium (Ti). Each metal coating provides distinct properties and aesthetic effects.

The diagram further indicates the incorporation of float glass (Step 4) into the coated products, offering choices such as Clear, Green, Grey, Bronze, Dark Grey, and Blue float glass with varying thicknesses from 2mm to 12mm. To safeguard the coated surfaces, the process includes the final step of applying the Plastic Pressure/Heat-Sensitive Surface Protection Film (Step 5), which ensures long-term preservation against potential damage, providing additional value and durability to the coated products. In overview the present Process Flow Block Diagram (PFBD) showcases a comprehensive and efficient methodology for integrating an array of coating and protection technologies, enabling manufacturers and designers to create visually appealing, long-lasting, and versatile products for a wide range of applications
Figure 4: Description: Figure 15 illustrates the innovative screen printing apparatus designed for achieving precise and uniform ink coating on glass surfaces. The apparatus comprises an aluminum frame (19) supporting a fabric cloth (16) with a mesh size ranging from 66 to 120 microns. The fabric cloth is tightly attached to the frame with a tension of approximately 15 to 24 Nm/cm², enabling controlled ink flow during the printing process. To ensure even ink distribution, a rubber squeegee (18) is mounted on a separate aluminum frame (17) and is employed to spread the ink in a uniform manner over the fabric mesh.
Figure 5: Describes about the screen printing process involves coating the fabric mesh with ink using a to and fro motion. Subsequently, the screen is positioned over the glass surface, and employing the same motion, the ink is transferred onto the glass, creating a consistent and well-defined pattern. For seamless maneuverability during the printing process, hinges (10) are strategically fixed on the table, allowing easy pivotal movement of the screen. The figure also describes the design functionality of this screen printing apparatus, enabling precise and efficient ink application on glass surfaces, thereby enhancing the quality and aesthetics of the printed designs. The apparatus' ability to create uniform coatings with ease contributes to improved productivity and expanded possibilities for glass printing applications across various industries.
Figure 6: Illustrates an advanced Online Curing/Baking System designed for curing printed ink on glass surfaces with meticulous precision. The system comprises a loading section (20) equipped with a roller conveyor, where glass panels are loaded with the ink side facing upward, ready for the curing process.
The curing process commences as the loaded glass moves into the heating section (21). A detailed depiction of the heating section is provided below the main figure. The heating section features a set of heaters in the form of rods (26) utilizing electrical resistance to generate controlled and uniform heat.
The curing process is tailored to meet the specific requirements of the ink used for printing on the glass. By precisely regulating the temperature and duration of heating, the system ensures optimal curing and bonding of the ink to the glass surface.
The online curing/baking system's innovative design and accurate heating control contribute to enhanced efficiency, reduced curing time, and improved print quality. It facilitates high-throughput production of cured glass products with vibrant and long-lasting printed designs, catering to diverse industries such as architectural glass, automotive glass, and decorative glass applications.

Figure 7: Describes the results of the elemental composition analysis using X-ray photoelectron spectroscopy show a single layer of chromium deposited on a glass substrate.

Figure 8: Describes the experimental results of taber test (Adhesion test) with and without overcoat layer, with 300 cycles.
Figure 9: presents the baking temperature of printed ink on float glass substrate at 60°C for a duration of 12 minutes. It has revealed that suboptimal curing outcomes and inadequate adhesion properties. This observation is evident from the tape test, where the ink exhibits susceptibility to removal from the glass substrate, adhering predominantly to the glass surface. Additionally, findings from the scratch test indicate that the ink on the printed side is prone to facile scratching, indicative of insufficient curing and a relatively malleable ink state.
Figure 10: presents the baking temperature of printed ink on float glass substrate at 140°C for a duration of 12 minutes conclusively demonstrates complete curing, eliminating any residual softness within the ink composition. Furthermore, visual analysis of the depicted illustration confirms the absence of ink adhesion onto the tape substrate. This substantiates the enhanced adhesive characteristics of the ink.
Figure 11: Modulating the proportions of ink constituents yields diverse outcomes. As depicted in the provided diagram, augmenting the proportion of the solvent within the ink by 10% and subsequently subjecting it to a 140°C baking process lasting 12 minutes reveals compromised ink adhesion, particularly evident when subjected to a cross-cut test. Examination of the test outcomes underscores an elevated rate of paint removal. The ink layer thickness measures below 10 microns.
Figure 12: Iillustrates in the provided figure, maintaining the solvent content within the range of 15% to 20% and subjecting the ink to a 140°C baking process lasting 12 minutes showcases commendable ink adhesion upon undergoing a cross-cut test. The ink layer thickness aligns with the desired specification of being above 10 microns. Evaluation of the test outcomes reveals a noticeable reduction in the extent of ink removal, indicating favorable results

DESCRIPTION OF THE INVENTION:
In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however that it is not intended to limit the disclosure to the specific forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the disclosure.

The invention provides a mirror glass door technology, specifically designed for use in refrigerator doors and other applications. The mirror glass door enhances the aesthetic appeal and durability of refrigerator doors by utilizing tempered glass with a metallic/metal composite layer coated with protective organic paint.
The mirror glass door technology as provided by the present invention is widely applicable in glass door systems, with a primary focus on refrigerator doors. Leveraging these reflective properties, the developed refrigerator door mirror aims to enhance the aesthetic appeal and functionality of refrigerator doors through the use of tempered glass with a metallic/metal composite layer.
The developed product, with its multi-layered coating, has potential applications in various industries, including glass refrigerator doors and decorative mirror products. This patent application aims to protect the innovative process and its resulting coated product, which offers unique advantages over existing methods and products.
The developed mirror glass door technology offers several advantages, including enhanced optical reflectivity, scratch resistance, and corrosion resistance. The door's eco-friendly design promotes the reutilization of glass, reducing the environmental impact of the production process. Additionally, the mirror glass door is versatile and suitable for various glass door applications beyond refrigerators, such as interior glasses, room cabinet separators, and large rear/front view mirrors.
The technology also streamlines the manufacturing process by eliminating multiple manual operations and reducing the likelihood of wrinkling in the metallized plastic. Overall, the developed mirror glass door presents an innovative solution that addresses existing limitations and significantly improves the performance, aesthetics, and eco-friendliness of glass door applications, particularly for refrigerators and other related products.
In an embodiment, the coated glass is subjected to controlled baking at specific temperatures and time intervals to achieve the desired characteristics, providing improved optical reflectivity, scratch resistance, and corrosion resistance. The technology offers a versatile solution suitable for various applications, including refrigerator doors, interior glasses, room cabinet separators, and large rear/front view mirrors. This patent aims to protect the novel process and product, which supersedes traditional plastic/steel/aluminium doors, offering better aesthetics and reduced manufacturing complexity.
In an embodiment, the mirror glass door applications revolutionize conventional plastic, steel, and aluminium doors by streamlining production processes. With the elimination of numerous manual operations and machine forming of the frame from aluminium roll stock, the mirror glass door significantly reduces the likelihood of wrinkling in the metallized plastic. Moreover, by facilitating the reutilization of glass in a recyclable manner during production, this innovative door technology positively impacts the environment.
The smooth peripheral surface of the mirror glass door, raised from the frame surface, offers improved aesthetics, setting it apart from standard doors.
The versatility of the developed technology allows its implementation in various applications beyond refrigerator doors. Interior glasses, room cabinet separators, and large rear/front view mirrors are among the potential use cases that benefit from the advanced mirror glass doors.
In an embodiment, the mirror glass door coating for refrigerator and glass door, comprising atleast a layer of tempered glass present in the thickness ranging from 2 to 8 mm, a metallic/metal composite layer present in the thickness ranging from about 5 -500 Å, a protective organic paint present in the thickness ranging from 1 – 400 micron.
In an embodiment, the mirror glass door coating, comprises:
a) the tempered glass substrate comprises thickness ranging from 2 to 8 mm;
b) metal layer selected from Cr, NiCr, Ag, SS, Al of thickness ranging from 10 to 90nm;
c) Protective overcoat layer selected from Si3N4 or SiO2 present in the thickness ranging from 2 to 40nm;
d) paint layer present in the thickness ranging from 10000 to 800000nm.

In an embodiment, the developed layer stack has two process of coatings one which physical vapour deposition technique (large area magnetron sputtering) and the other with screen/ spray painting technology. The developed metallic/metal layer will be used any transition metallic layer and its composite in the periodic table. The developed metallic layers mainly consists of any one of the metal layer among the materials Cr, NiCr, Ag, SS, Al.
In an embodiment, the developed layer contains a protective overcoat layer with Si3N4, or SiO2.
In an embodiment, apart from that metal layer coating, the product is printed with screen/spray printing technology with organic materials for protecting the coated film surface. Finally the finished product is protected with surface protection film to avoid the scratches on the surface of the glass.
In an embodiment, the mirror glass door for refrigerator and glass door applications, comprises:
• a tempered glass substrate with a thickness ranging from 2.0 to 5 mm or 2 to 8 mm or 2.0 to 3.5 mm;
• a metallic/metal composite layer deposited on the surface of the tempered glass substrate using Physical Vapour Deposition (PVD) technique, wherein the metallic/metal composite layer comprises one or more metals selected from the group consisting of Cr, NiCr, Ag, SS, and Al;
In an embodiment, a protective overcoat layer deposited by using the materials si3N4 or SiO2, which is used to protect the metallic layer against the scratches and improves the durability of coating.
In an embodiment, a protective organic paint layer applied over the metallic/metal composite layer to enhance optical reflectivity, scratch resistance, and corrosion resistance of the mirror glass door.
In an embodiment, the metallic/metal composite layer is deposited using large-area magnetron sputtering in a high vacuum environment at a pressure of 10 x E-6 mbar.
In an embodiment, the mirror glass door as described above, wherein the metallic/metal composite layer is deposited at room temperature.
In an embodiment, the mirror glass door of any preceding claim, further comprising a screen/spray-printed metallic shade logo on the tempered glass substrate, wherein the logo is baked at a temperature ranging from 70 to 150 or 80 to 120 or 100 to 120 degrees Celsius for a time interval of 10 to 15 minutes.
In an embodiment, the mirror glass door of any preceding claim, wherein the protective organic paint layer is applied using screen/spray printing technology.
In an embodiment, the mirror glass door of any preceding claim, further comprising a final top black paint layer screen/spray-printed over the metallic/metal composite layer to enhance aesthetic appeal and durability.
In an embodiment, the mirror glass door of any preceding claim, further protected with a surface protection film applied to the tempered glass substrate to prevent scratches and fingerprints during transportation.
In an embodiment, the method for manufacturing a mirror glass door, comprises the steps of:
a) Printing a metallic shade logo on a tempered glass substrate using screen printing technology;
b) Baking the printed logo at a temperature ranging from 70 to 150 or 80 to 120 or 100 to 120 degrees Celsius for a time interval of 10 to 15 minutes;
c) Depositing a metallic/metal composite layer on the tempered glass substrate using Physical Vapour Deposition (PVD) technique, wherein the metallic/metal composite layer comprises one or more metals selected from the group consisting of Cr, NiCr, Ag, SS, and Al;
d) Applying a protective organic paint layer over the metallic/metal composite layer using screen/spray printing technology;
e) Applying a final top black paint layer over the metallic/metal composite layer using screen/spray printing technology;
f) Applying a surface protection film on the tempered glass substrate to protect the mirror glass door from scratches and fingerprints during transportation.
In an embodiment, the deposition of the metallic/metal composite layer is performed in a high vacuum environment at a pressure of 10 x E-6 mbar using large-area magnetron sputtering.
In an embodiment, the metallic/metal composite layer is deposited at room temperature.
In an embodiment, the monolithic coated glass deposited with a single layer of metallic film will have a visible light transmission (Tr y) ranging between 15 % and 35 %
In an embodiment, the monolithic coated glass deposited with a single layer of metallic film followed by overcoat will have a visible light transmission (Tr y) ranging between 15 % and 35 %
In an embodiment, monolithic coated glass deposited with a single layer of metallic film followed by overcoat and paint layer will have a visible light reflection (Rg y) ranging between 18 % to 35 %; Rf y ranging between 2 % and 40 %
In an embodiment, the monolithic coated glass deposited with a single layer of metallic film followed paint layer will have a visible light reflection (Rg y) ranging between 18 % to 35 %; Rf y ranging between 2 % and 40 %
In an embodiment, the monolithic coated glass deposited with a single layer of metallic film will have a visible light reflection (Rg y) ranging between 18 % to 35 %; Rf y ranging between 2 % and 40 %
In an embodiment, the Coated glass article as claimed in any of the preceding claims is a monolithic mirror with back painted for the applications related to refrigerator glass door, interior decorative applications.
In an embodiment, the metallic coated article measured monolithically has a visible light transmission a* value from -1 to -8 and b* value from -1 to -8; glass side reflective a* value of from -1 to -8 and b* value from 1 to -8; film side reflective a* value -1 to -8 and b* value from 1 to -8
In an embodiment, the metallic coated article with back paint measured monolithically has a visible light transmission a* value from -1 to -8 and b* value from -1 to -8; glass side reflective a* value of from -1 to -8 and b* value from 1 to -8; film side reflective a* value -1 to -8 and b* value from 1 to -8
In an embodiment, the metallic coated article with overcoat measured monolithically has a visible light transmission a* value from -1 to -8 and b* value from -1 to -8; glass side reflective a* value of from -1 to -8 and b* value from 1 to -8; film side reflective a* value -1 to -8 and b* value from 1 to -8
In an embodiment, the metallic coated article with overcoat followed by back paint measured monolithically has a visible light transmission a* value from -1 to -8 and b* value from -1 to -8; glass side reflective a* value of from -1 to -8 and b* value from 1 to -8; film side reflective a* value -1 to -8 and b* value from 1 to -8
In an embodiment, the metallic layer thickness is from about 5 -500 Å

In an embodiment, the overcoat protective layer thickness is from about 5 -500 Å

In an embodiment, the back painted layer thickness is from about 1 – 400 micron.
In an embodiment, the screen printing on the float glass substrate is performed by paint, hardener and thinner, wherein paint is present in an amount of 1kg, hardener is present in an amount of 1 to 50% of the amount of the paint and thinner is present in an amount of 1 to 50% of the amount of the paint.

The Invention is further described with the help of non-limiting examples:
Example 1:
Development of Mirror Glass Door:
The mirror glass door is constructed using temperable glass, harnessing its heat-strengthening properties to enhance structural integrity beyond that of standard glass. The raw glass materials employed in this innovative product vary in thickness, ranging from 2.0 to 5 mm or 2 to 8 mm, or 2.0 to 3.5 mm, offering flexibility in design and application.
First the metallic shade logo is printed on the tempered glass after that the printed logo will be baked in the oven at 70 to 150 or 80 to 120 or 100 to 120 degrees temperature for a time interval 10 to 15 minutes. Further, the metallic/metal composite layer, specifically designed for refrigerator door applications, is expertly coated onto the tempered or non-tempered glass surface. To enable the reflective property, a protective organic ink/paint is meticulously applied over the coated layer. This assembly undergoes a carefully controlled thermal process, subjecting the coated glass to temperatures between 50 to 200 or 70 to 150 or 80 to 140 degrees, for varying time intervals ranging from 10 to 60 or 20 to 40 or 40 to 50 minutes, ensuring the desired characteristics are achieved.
Example 2:
Process steps involved in the development of the product
The present document pertains to a patent application for a novel fabrication process of a developed product using 4 ways.
Step 1: The tempered glass coated with chrome metallic shade by using the screen printing technology
Step 2: By using the Physical Vapour Deposition (PVD) technique with large area RF/DC magnetron sputtering the deposition process is carried out. The unique coating system utilized in the process involves a sequential layer method, and the entire procedure takes place in a high vacuum environment at a pressure of 10×E-6 mbar. The coating process is carried out on a glass substrate at room temperature using transition metals from the periodic table, such as Cr, NiCr, SS, Ag, Al layers with and without protection layers using Si3N4 or SiO2.
To achieve the required vacuum pressure, a combination of low and high-pressure pumps, including roots and rotary pumps for low pressure (10×E-3 mbar) and a turbo molecular pump for high vacuum (10×E-6 mbar), is employed. The deposition of each layer is facilitated by creating a 4th state of matter plasma using Argon gas, where the neutral argon atoms are ionized and accelerated towards the negatively charged target.
Step 3: Furthermore, the product's aesthetic appeal and durability are enhanced by applying a final top black paint layer using screen/spray printing technology. This screen-printed layer adds a visually appealing finish to the coated glass and ensures enhanced durability.
Step 4: finally the developed product will be protected by applying the Protective film on the surface of the glass to avoid the scratches, finger prints during the transportation.
Example 3:
Experimental results
Table 1: Presents the thickness of the single layer in the figure 1 and 2 embodiment
Layer General
Thickness (nm) Preferred Thickness (nm) Most Preferred Thickness (nm)
Cr 10-90 10-70 10-45
Glass 2 – 12 mm 2 -6 mm 2- 4 mm

Table 2: Presents the color/ optical performance parameter values of the single layer for the figure 1 and 2 embodiment
Color/ optical performance parameter values (monolithic substrate)
General Preferred Most preferred
TR Y 40-10 35-10 30-10
L* 90-30 75-45 65-50
a* 1-(-8) 1-(-5) 1-(-2)
b* 1-(-8) 1-(-5) 1-(-2)
RG Y 70-10 55-12 35-15
L* 90-30 75-45 65-50
a* 1-(-8) 1-(-5) 1-(-2)
b* 1-(-8) 1-(-5) 1-(-2)
RF Y 80-10 65-15 45-25
L* 90-30 85-45 75-50
a* 1-(-8) 1-(-5) 1-(-2)
b* 1-(-8) 1-(-5) 1-(-2)

Table 3: Presents the experimental values of single layer coated layer (monolithic substrate) by using large area magnetron sputter coating
Example 1
TR L* 51.46
a* -0.09
b* -1.03
X 18.63
Y 19.67
Z 21.67
RG L* 51.23
a* -2.3
b* 0.76
X 18.02
Y 19.46
Z 20.48
RF L* 66.62
a* -0.76
b* 1.1
X 34.04
Y 36.14
Z 37.89

Table 4: Presents the thickness of the coated layers in the figure 1 and 2 embodiment
Material General Thickness (nm) Preferred Thickness (nm) Most Preferred Thickness (nm)
Glass 2 – 12 mm 2 -6 mm 2- 4 mm
Cr 10-90 10-70 10-45
Paint 10000-800000 10000-500000 10000-250000

Table 5: Presents the color/ optical performance parameter values of the coated layers with back painting for the figure 1 and 2 embodiment
Color/ optical performance parameter values (monolithic substrate)
General Preferred Most preferred
TR Y 0-10 0-5 0-2
L* 0-10 0-5 0-2
a* 1-(-8) 1-(-5) 1-(-2)
b* 1-(-8) 1-(-5) 1-(-2)
RG Y 70-10 55-12 35-15
L* 90-30 75-45 65-50
a* 1-(-8) 1-(-5) 1-(-3)
b* 1-(-8) 1-(-5) 1-(-2)
RF Y 0-10 0-5 0-3
L* 0-10 0-5 0-2
a* 1-(-8) 1-(-5) 1-(-2)
b* 1-(-8) 1-(-5) 1-(-2)

Table 6: Presents the experimental values of single layer coated layer (monolithic substrate) by using large area magnetron sputter coating and with back painting

Example 2
TR L* 0.06
a* 0.1
b* -0.11
X 0.01
Y 0.01
Z 0.02
RG L* 56.09
a* -2.59
b* 0.12
X 22.19
Y 24
Z 25.68
RF L* 23.27
a* -0.45
b* -0.93
X 3.65
Y 3.88
Z 4.34

Table 7: Presents the thickness of the coated layers, with protective overcoat in the figure 1 and 2 embodiment
Material General Thickness (nm) Preferred Thickness (nm) Most Preferred Thickness (nm)
Cr 10-90 10-70 10-45
Si3N4 2-40 5-30 5-20

Table 8: Presents the color/ optical performance parameter values of the coated layers with overcoat for the figure 1and 2 embodiment
Color/ optical performance parameter values (monolithic substrate)
TR General Preferred Most preferred
Y 40-10 35-10 30-10
L* 90-30 75-45 65-50
a* 1-(-8) 1-(-5) 1-(-2)
RG b* 1-(-8) 1-(-5) 1-(-2)
Y 70-10 55-12 35-15
L* 90-30 75-45 65-50
a* 1-(-8) 1-(-5) 1-(-2)
RF b* 1-(-8) 1-(-5) 1-(-2)
Y 80-10 65-15 45-25
L* 90-30 85-45 75-50
a* 1-(-8) 1-(-5) 1-(-2)
b* 1-(-8) 1-(-5) 1-(-2)

Table 9: Presents the experimental values of coated layer with overcoat (monolithic substrate) by using large area magnetron sputter coating

Example 3
TR L* 49.25
a* -0.04
b* -3.04
X 16.86
Y 17.79
Z 56.34
RG L* 65.25
a* -2.5
b* 1.17
X 24.25
Y 25.3
Z 22.65
RF L* 24.27
a* -0.39
b* 6.02
X 34.36
Y 32.32
Z 37.89

Table 10: Presents the thickness of the coated layers, with protective overcoat with back painting in the figure 1 and 2 embodiment
Material General Thickness (nm) Preferred Thickness (nm) Most Preferred Thickness (nm)
Glass 2 – 12 mm 2 -6 mm 2- 4 mm
Cr 10-90 10-70 10-45
Si3N4 or SiO2 2-40 5-30 5-20
Paint 10000-800000 10000-500000 10000-250000

Table 11: Presents the color/ optical performance parameter values of the coated layers with overcoat and back painting for the figure 1and 2 embodiment
Color/ optical performance parameter values (monolithic substrate)
General Preferred Most preferred
TR Y 0-10 0-5 0-2
L* 0-10 0-5 0-2
a* 1-(-8) 1-(-5) 1-(-2)
b* 1-(-8) 1-(-5) 1-(-2)
RG Y 70-10 55-12 35-15
L* 90-30 75-45 65-50
a* 1-(-8) 1-(-5) 1-(-3)
b* 1-(-8) 1-(-5) 1-(-2)
RF Y 0-10 0-5 0-3
L* 0-10 0-5 0-2
a* 1-(-8) 1-(-5) 1-(-2)
b* 1-(-8) 1-(-5) 1-(-2)

Table 12: Presents the experimental values of coated layer with overcoat and back painting (monolithic substrate) by using large area magnetron sputter coating

Example 4
TR L* 0.08
a* 0.15
b* -0.13
X 0.01
Y 0.01
Z 0.01
RG L* 61.2
a* -2.79
b* 0.53
X 26.62
Y 28.79
Z 30.5
RF L* 21.9
a* -0.08
b* 3.99
X 2.08
Y 2.1
Z -1.23

Table 9A: Adhesion test, Presents the experimental test values with 300 cycles of coated layer (monolithic substrate) deposited by using large area magnetron sputter coating

colors values (before taber) color values
(After taber) Deviation Remark
TR L* 51.46 59.76 8.3 Fail
a* -0.09 -0.02 0.07
b* -1.03 -0.73 0.3
X 18.63 26.41 7.78
Y 19.67 27.86 8.19
Z 21.67 30.41 8.74

Table 10A: Adhesion test, Presents the experimental test values with 300 cycles of coated layer with protective overcoat layer (monolithic substrate) deposited by using large area magnetron sputter coating
colors values (before taber) color values
(After taber) Deviation Remark
TR L* 49.25 50.46 1.21 Pass
a* -0.04 -0.06 -0.02
b* -3.04 -3.4 -0.36
X 16.86 17.82 0.96
Y 17.79 18.8 1.01
Z 20.69 22.03 1.34

Example 3:
The experiments for various tests, were performed to evaluate the importance of the baking temperature while printing ink on the float glass substrate. The results are mentioned below:
Figure 9: presents the baking temperature of printed ink on float glass substrate at 60°C for a duration of 12 minutes. It has revealed that suboptimal curing outcomes and inadequate adhesion properties. This observation is evident from the tape test, where the ink exhibits susceptibility to removal from the glass substrate, adhering predominantly to the glass surface. Additionally, findings from the scratch test indicate that the ink on the printed side is prone to facile scratching, indicative of insufficient curing and a relatively malleable ink state.
Figure 10: presents the baking temperature of printed ink on float glass substrate at 140°C for a duration of 12 minutes conclusively demonstrates complete curing, eliminating any residual softness within the ink composition. Furthermore, visual analysis of the depicted illustration confirms the absence of ink adhesion onto the tape substrate. This substantiates the enhanced adhesive characteristics of the ink.
Figure 11: Modulating the proportions of ink constituents yields diverse outcomes. As depicted in the provided diagram, augmenting the proportion of the solvent within the ink by 10% and subsequently subjecting it to a 140°C baking process lasting 12 minutes reveals compromised ink adhesion, particularly evident when subjected to a cross-cut test. Examination of the test outcomes underscores an elevated rate of paint removal. The ink layer thickness measures below 10 microns.
Figure 12: Iillustrates in the provided figure, maintaining the solvent content within the range of 15% to 20% and subjecting the ink to a 140°C baking process lasting 12 minutes showcases commendable ink adhesion upon undergoing a cross-cut test. The ink layer thickness aligns with the desired specification of being above 10 microns. Evaluation of the test outcomes reveals a noticeable reduction in the extent of ink removal, indicating favorable result.
Example 4:
Table 12: The below table shows variation in the properties of the final glass coating with respect to the change in the thickness of the metal layer (like Cr, NiCr, Ag, SS, Al). It is seen that the best properties are being achieved when the metallic layer is present in the thickness of 30nm. However, the other metal layers are also working satisfactorily.
Example 1 Example 2 Example 3 Example 4 Example 5
Thickness (nm) 10.00 30.00 50.00 70.00 80.00
Cathode Power (Kwh) 3.83 11.50 19.17 26.83 30.67

Tr Y 44.65 17.97 8.87 4.23 2.84
L* 72.63 49.39 35.60 24.22 19.21
a* -0.21 0.14 0.69 1.57 1.90
b* 1.12 2.14 4.56 6.57 6.94
Rg Y 6.78 22.99 28.71 25.80 24.15
L* 31.30 55.06 60.52 57.85 56.24
a* -0.41 -1.00 -0.28 0.68 0.69
b* -0.38 0.96 4.67 6.04 5.24
Rf Y 20.82 38.76 41.04 37.05 35.62
L* 52.75 68.58 70.21 67.32 66.23
a* -0.31 -0.03 0.78 1.38 1.25
b* -0.65 1.62 5.07 5.42 4.55

Example 5:
Table 13: Describes the baking conditions and finalizing the standard temperature for proper curing of deposited screen printing ink on the float glass substrate
Trial No. Temperature (°C) Time (min) Result
Exp 1 60 12 Fail
Exp 2 80 12 Acceptable
Exp 3 100 12 Acceptable
Exp 4 120 12 Pass
Exp 5 140 12 Pass
Exp 6 180 12 Pass
Exp 7 200 12 Pass

Example 6:
Table 14: Describes the ratio of paint, hardener, and thinner for finalizing the standard ratio to print the screen printing process on the float glass substrate
Trial No. Ink / Paint(Kg) Hardener (% of Ink) Thinner (% of Ink) Result Remark
Exp 1 1 5 5 Fail Time to cure > 12 hours, Thick mixture chokes the screen
Exp 2 1 10 10 Fail Time to cure ~ 12 hours, Thick mixture chokes the screen
Exp 3 1 15 15 Acceptable Time to cure < 8 hours, need to increase flow ability of ink
Exp 4 1 20 20 Acceptable Time to cure < 4 hours
Exp 5 1 25 20 Pass Time to cure < 2 hours
Exp 6 1 30 20 Pass Time to cure < 1 hour
Exp 7 1 40 30 Fail Ink dries out very quickly, Cross-cut test: fail

Example 7:
The method of manufacturing the mirror glass door coating as described above, comprises the steps of:
a) printing a metallic shade logo on a tempered glass substrate using screen printing technology ;
b) baking the printed logo at a temperature ranging from 70 to 150 or 80 to 120 or 100 to 120 degrees Celsius for a time interval of 10 to 15 minutes;
c) depositing a metallic/metal composite layer on the tempered glass substrate using Physical Vapour Deposition (PVD) technique, wherein the metallic/metal composite layer comprises one or more metals selected from the group consisting of Cr, NiCr, Ag, SS, and Al;
d) applying a protective organic paint layer over the metallic/metal composite layer using screen/spray printing technology;
e) applying a final top black paint layer over the metallic/metal composite layer using screen/spray printing technology;
f) applying a surface protection film on the tempered glass substrate to protect the mirror glass door from scratches and fingerprints during transportation.

Example 8:
The method as claimed in claim 3, wherein the method also comprises the steps of:
a) Cleaning and applying primer to the surface to be coated;
b) coating the surface by epoxy based or Pu-based organic/ inorganic ink coating, UV-curing ink coating or ceramic-based ink coating or traditional paint coating
c) baking at the temperature ranging from 70 to 150 or 80 to 120 or 100 to 120 degrees Celsius for a time interval of 10 to 15 minutes;
d) performing metal coating on the surface obtained in step (c) wherein the metal comprises Chromium (Cr), Nickel-Chromium (NiCr), Aluminum (Al), Silver (Ag), Stainless Steel (SS), and Titanium (Ti), wherein the metallic/metal composite layer is deposited using large-area magnetron sputtering in a high vacuum environment at a pressure of 10 x E-6 mbar, at room temperature;
g) incorporating the float glass into the coated surface, wherein the float glass comprises Clear, Green, Grey, Bronze, Dark Grey, and Blue float glass with varying thicknesses from 2mm to 12mm;
h) applying the Plastic Pressure/Heat-Sensitive Surface Protection Film.

The metal layer comprises chromium layer of thickness ranging from 10 to 90nm. The protective organic paint layer is applied using screen/spray printing technology. The desired vacuum pressure is obtained by the combination of low and high-pressure pumps, including roots and rotary pumps for low pressure (10×E-3 mbar) and a turbo molecular pump for high vacuum (10×E-6 mbar). The deposition of each layer is facilitated by creating a 4th state of matter plasma using Argon gas, where the neutral argon atoms are ionized and accelerated towards the negatively charged target. The screen printing on the float glass substrate is performed by paint, hardener and thinner, wherein paint is present in an amount of 1kg, hardener is present in an amount of 1 to 50% of the amount of the paint and thinner is present in an amount of 1 to 50% of the amount of the paint.
, Claims:We Claim:
1. A mirror glass door coating for refrigerator and glass door, comprising atleast a layer of tempered glass present in the thickness ranging from 2 to 8 mm, a metallic/metal composite layer present in the thickness ranging from about 5 -500 Å, a protective organic paint present in the thickness ranging from 1 – 400 micron.

2. The mirror glass door coating as claimed in claim 1, wherein:
a) the tempered glass substrate comprises thickness ranging from 2 to 8 mm;
b) metal layer selected from Cr, NiCr, Ag, SS, Al of thickness ranging from 10 to 90nm;
c) Protective overcoat layer selected from Si3N4 or SiO2 present in the thickness ranging from 2 to 40nm;
d) paint layer present in the thickness ranging from 10000 to 800000nm.

3. A method of manufacturing the mirror glass door coating as claimed in claim 1, comprising the steps of:
a) printing a metallic shade logo on a tempered glass substrate using screen printing technology ;
b) baking the printed logo at a temperature ranging from 70 to 150 or 80 to 120 or 100 to 120 degrees Celsius for a time interval of 10 to 15 minutes;
c) depositing a metallic/metal composite layer on the tempered glass substrate using Physical Vapour Deposition (PVD) technique, wherein the metallic/metal composite layer comprises one or more metals selected from the group consisting of Cr, NiCr, Ag, SS, and Al;
d) applying a protective organic paint layer over the metallic/metal composite layer using screen/spray printing technology;
e) applying a final top black paint layer over the metallic/metal composite layer using screen/spray printing technology;
f) applying a surface protection film on the tempered glass substrate to protect the mirror glass door from scratches and fingerprints during transportation.

4. The method as claimed in claim 3, wherein the method also comprises the steps of:
a) Cleaning and applying primer to the surface to be coated;
b) coating the surface by epoxy based or Pu-based organic/ inorganic ink coating, UV-curing ink coating or ceramic-based ink coating or traditional paint coating
c) baking at the temperature ranging from 70 to 150 or 80 to 120 or 100 to 120 degrees Celsius for a time interval of 10 to 15 minutes;
d) performing metal coating on the surface obtained in step (c) wherein the metal comprises Chromium (Cr), Nickel-Chromium (NiCr), Aluminum (Al), Silver (Ag), Stainless Steel (SS), and Titanium (Ti), wherein the metallic/metal composite layer is deposited using large-area magnetron sputtering in a high vacuum environment at a pressure of 10 x E-6 mbar, at room temperature;
g) incorporating the float glass into the coated surface, wherein the float glass comprises Clear, Green, Grey, Bronze, Dark Grey, and Blue float glass with varying thicknesses from 2mm to 12mm;
h) applying the Plastic Pressure/Heat-Sensitive Surface Protection Film.

5. The method as claimed in claim 3, wherein the metal layer comprises chromium layer of thickness ranging from 10 to 90nm.
6. The method as claimed in claim 3, wherein the protective organic paint layer is applied using screen/spray printing technology.
7. The method as claimed in claim 3, wherein the desired vacuum pressure is obtained by the combination of low and high-pressure pumps, including roots and rotary pumps for low pressure (10×E-3 mbar) and a turbo molecular pump for high vacuum (10×E-6 mbar).
8. The method as claimed in claim 3, wherein the deposition of each layer is facilitated by creating a 4th state of matter plasma using Argon gas, where the neutral argon atoms are ionized and accelerated towards the negatively charged target.
9. The method as claimed in claim 3, wherein the screen printing on the float glass substrate is performed by paint, hardener and thinner, wherein paint is present in an amount of 1kg, hardener is present in an amount of 1 to 50% of the amount of the paint and thinner is present in an amount of 1 to 50% of the amount of the paint.