Patent Description:
Document <CIT> discloses a display-equipped multilayer glass with improved visibility of a display image of a transparent display and of the background of the transparent display. The multilayer glass comprises a plurality of glass plates stacked with spacers therebetween, wherein the spacers are provided to the peripheral edges of the plates. Hollow layers are formed between the plurality of glass plates, and a transparent display is disposed on a surface that faces the hollow layer of at least one glass plate of the plurality of glass plates.

Refrigerated display coolers are used in convenience stores, markets, food vending operations, and the like, to keep products, for example beverages and perishable food products, cool. Typically, such display coolers have a refrigerated compartment and an opening that is sealed by a door that can be opened by a consumer to retrieve the desired product.

Refrigerated display coolers consume a considerable amount of electricity during operation. It is therefore desirable to employ technologies that reduce the display cooler's electricity usage to save on operating costs, improve energy efficiency and reduce the CO<NUM> footprint (among others) of the cooler. One method of reducing the electricity usage is to make the refrigerated display cooler, itself, more thermally insulative. For example, more insulation could be added to the refrigerated compartment. However, the physical footprint of a display cooler is often constrained, and thicker insulation would mean reducing the total available storage space inside the cooler, thereby reducing the number of items for sale that can be stocked inside the cooler.

Another mechanism for improving thermal performance is to make the display cooler door more insulative. A typical display cooler door comprises a frame surrounding an insulated glass unit (IGU). An IGU typically comprises two or more sheets of glass sealed at their peripheral edges by a seal. The sheets of glass are spaced apart, and the space between each sheet of glass, once sealed, can be filled with an inert gas, such as argon or krypton. In doing so, the insulative or thermal performance of the display cooler door can be improved.

In addition to improving thermal performance, a display cooler door IGU that is more thermally insulative also needs to meet other design constraints. These constraints include: (<NUM>) minimized mass for stability purposes of the IGU and to reduce weight-based shipping costs; (<NUM>) maximized visible transmittance through the IGU so customers can see displayed products; (<NUM>) minimized door thickness to prevent storage space from being reduced (once the display door is closed) to maintain a constrained cooler footprint and to utilize existing hardware (for improved upgrade and cost control purposes for such potential retrofitting, among others); (<NUM>) robust mechanical design to prevent IGU breakage when the door is cycled during typical consumer interaction and usage thereof; and (<NUM>) minimized manufacturing cost, by using existing hardware, for example. One way of improving the thermal performance of an IGU is to increase the number of glass panes from two to three. Although increasing the number of glass panes used in the IGU can improve the thermal performance of the IGU, conventional triple pane IGUs fail to meet the other design constraints, especially the weight and visibility constraints. Accordingly, a display cooler IGU that has improved thermal insulation properties and that can also satisfy the other design constraints is needed in the industry.

At least one embodiment of the present technology provides an insulated glass unit (i.e., IGU) having at least first, and second glass panes, with at least one glass pane having a thickness of <NUM> or less, alternatively a thickness of <NUM> or less. In some embodiments, the glass panes have thicknesses that differ from one another.

In some aspects, any one or more of the glass panes is strengthened, and any one or more of the glass panes may be coated with a low emissivity coating or other thermally insulative coating. In one or more embodiments, any one or more of the glass panes may form part of an electronic display (e.g., an LCD display), a portion of a back light unit (BLU), function as a waveguide or light guide plate (LGP), form a touch function surface, provide thermal insulation, provide rigidity and/or mechanical structural strength, and combinations thereof.

Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows; the claims; as well as the appended drawings.

Reference will now be made in detail to various non-limiting embodiments of the present technology, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

<FIG> provides an exemplary display cooler door <NUM> comprising a door frame <NUM> surrounding a triple pane insulated glass unit <NUM>. The display cooler door <NUM> can be mounted to a frame which defines an opening in the display cooler. The display cooler door <NUM> can be swung or slid open or closed to alternately seal or unseal the interior space of the display cooler and allow access to items stored in the display cooler.

The insulated glass unit <NUM> is illustrated in <FIG> and comprises according to the invention three glass panes <NUM>, <NUM>, and <NUM>, respectively. An outermost glass pane <NUM> can be positioned so that its outer surface <NUM> faces the ambient external environment or the "warm side" of the display cooler. An innermost glass pane <NUM> can be positioned so that its outer surface <NUM> faces the interior or "cold side" of the display cooler. A central pane <NUM> is disposed between and spaced apart from the glass pane <NUM> and the glass pane <NUM>. The central pane <NUM> can be positioned substantially parallel to the outer and inner glass panes <NUM>, <NUM> or can be canted away from or towards the outer or inner glass panes <NUM>, <NUM>.

In at least one embodiment of the present technology, the inner surface <NUM> of the outer glass pane <NUM> can be coated with a thermal coating, such as a low emissivity coating <NUM>. Low emissivity coatings are known in the art and include, without limitation, sputter-coated and pyrolytic coatings that provide a high level of thermal performance and a high visible light transmittance. Such coatings can be formed from a variety of metals and/or metal oxides, including silver, titanium, and fluorine doped tin oxide. Suitable low emissivity coatings include, for example, silver and metal oxide coatings.

In at least one alternative embodiment of the presently described technology, the inner surface <NUM> of the inner glass pane <NUM> can also be coated with a low emissivity coating <NUM>. The low emissivity coatings coated on the inner surfaces of the outer glass pane <NUM> and the inner glass pane <NUM> may be the same or different depending upon the desired properties and end use for the insulated glass unit. Combinations of coatings may also be used.

It should be noted that while the glass panes have been referenced here as a single glass sheet, the claims appended herewith should not be so limited as the glass panes can be a glass laminate structure including a glass-polymer laminate structure or a glass-glass laminate structure. Suitable glass-polymer laminate structures include a single sheet of glass laminated to a polymeric film, two sheets of glass having an intermediate polymeric film, and the like. Suitable glass-glass laminate structures include a structure having an inner glass core and one or two outer glass clad layers.

According to the invention, the central glass pane <NUM> is a "thin glass" pane. According to the invention, the outer and/or inner glass panes <NUM> and <NUM> are "thin glass" panes.

The thin glass panes described herein could also be made from soda lime glass using a float process. The float process could be conducted in a manner to obtain a soda lime glass pane having a desired thickness of about <NUM> or less. Alternatively, a conventional soda lime glass pane having a thickness of about <NUM> to about <NUM> could be polished down to a desired thickness of about <NUM> or less.

In some embodiments, using thin glass for the central pane provides several advantages not provided by a conventional display cooler (i.e., IGU) product. For example, thin glass (or thin glass panes) provides a reduced mass and better visibility compared to a conventional triple pane insulated glass unit having a thicker central pane. Thin glass can also provide better thermal insulation compared to a conventional triple insulated glass unit requiring a constrained thickness. In addition, enclosing the thin central pane <NUM> between the thicker outer and inner panes <NUM> and <NUM>, respectively, maintains a robust mechanical design that minimizes IGU breakage while providing enhanced thermal efficiency. According to the invention, the outer and inner panes <NUM> and <NUM> also include thin glass to further reduce weight and exhibit improved optical and strength requirements.

The central glass pane <NUM> and outermost glass pane <NUM> are spaced apart and can define a gap space <NUM> therebetween, and the central glass pane <NUM> and innermost glass pane <NUM> are spaced apart and define a gap space <NUM> therebetween. Both gap spaces are hermetically sealed by sealant assemblies known in the art. Such sealant assemblies can be formed from, for example, polymeric-based seals or other sealing material(s). The gap spaces are filled with an inert gas to improve the thermal performance of the insulated glass unit. Suitable inert gases include, but are not limited to, argon, krypton and xenon. Also, mixtures of inert gases, or mixtures of one or more inert gases and air can be used. Suitable mixtures include a mixture of <NUM>% argon and <NUM>% air, alternatively, a mixture of <NUM>% argon and <NUM>% air, alternatively, a mixture of <NUM>% krypton and <NUM>% air, or alternatively, a mixture of <NUM>% argon, <NUM>% krypton and <NUM>% air. Other ratios of inert gases, or inert gas and air, can also be used depending upon the desired thermal performance and end use of the insulated glass unit.

It should be appreciated by those skilled in the art utilizing the presently described technology that the gas pressure in the gap space <NUM> can differ from the gas pressure in the gap space <NUM>, in at least some embodiments. This could be due to a difference in the average gas temperature between the two spaces, since the gap space <NUM> is on the ambient, or warm, side of the insulated glass unit, while the gap space <NUM> is on the "cold" side, closer to the display cooler interior. The differential pressure could be sufficient to bow an exemplary thin central glass pane <NUM>. To prevent bowing from occurring, at least one channel or opening in the central pane <NUM> is provided to allow the gas in the gap space <NUM> to contact the gas in the gap space <NUM>. Although it is possible to drill one or more holes in the central glass pane <NUM> to provide the gas communication between the gap spaces, such drilling can be difficult with a thin glass pane and can result in cracks or breakage. One convenient way to allow the gases to come into contact is to change the outer perimeter shape of the central pane, such as by clipping one or more corners of the central pane, as shown in <FIG>. Changing the outer perimeter by removing or clipping a portion of the central pane results in a stronger central pane and less chance of cracks or breakage. When the central pane is sealed into the insulated glass unit, a clipped corner <NUM> can allow gas from the warm side gap space <NUM> to contact gas in the cold side gap space <NUM>. This contact removes the potential for differential pressure between the gap spaces and thereby minimizes or eliminates bowing.

It should also be appreciated by those skilled in the art that the thickness of the gap spaces <NUM> and <NUM> can be varied and can range from about <NUM> to about <NUM>. In some embodiments, any one or more of the gap spaces <NUM> and <NUM> (or any other gap spaces) may have a thickness in the range from about <NUM> to about <NUM>, or about <NUM>. In some embodiments, the thickness of the gap spaces <NUM>, <NUM> can be different. The total thickness of the insulated glass unit <NUM> can be about <NUM> or less, preferably about <NUM> or less, but can be at least about <NUM>. Desirable low U-values can be obtained when the gap spaces are in the range of about <NUM> to about <NUM> and the total thickness of the insulated glass unit is about <NUM> to about <NUM>. In some embodiments, for example where the footprint of the display cooler is constrained, the total thickness of the insulated glass unit can be about <NUM> to about <NUM>. A further benefit of having a thin glass central pane, especially for insulated glass units requiring a constrained thickness is that it allows for wider gap spaces. One drawback of constrained insulated glass units having narrow gap spaces is that there is a risk that contraction of the gasses in the gap spaces can cause the outer panes to bow and make contact with the central pane. This result is not only cosmetically unacceptable, it is unacceptable from an energy standpoint since it permits the direct conduction of heat into the cooler. Use of thinner glass panes allows for wider gaps and therefore reduces the risk of this problem.

In an example not according to the invention, at least one alternative insulated glass unit of the present technology is shown in <FIG>. This example is similar to the embodiment shown in <FIG> except that the insulated glass unit <NUM> comprises four glass panes instead of three: an outer glass pane <NUM>, an inner glass pane <NUM>, and two central glass panes <NUM> and <NUM> intermediate the outer glass pane <NUM> and the inner glass pane <NUM>. In one example, the outer and inner glass panes <NUM> and <NUM> can be formed from thick glass, for example, soda lime glass, and each can have a thickness in the range of about <NUM> to about <NUM>. In another example, the central glass panes are thin glass, having a thickness in the range from about <NUM> to about <NUM>, alternatively, from about <NUM> to about <NUM>. Alternatively or additionally, any one or more of the outer and inner glass panes <NUM> and <NUM> can be formed from thin glass panes, as described herein.

Alternatively or additionally, any one or more of the central glass panes may be thick glass panes.

In at least one example, any one or more of the glass panes (e.g., <NUM>, <NUM>, <NUM>, <NUM>) can be strengthened by thermal tempering, chemical strengthening or another suitable strengthening process. The inner surface <NUM> of the outer pane <NUM> of this embodiment can be coated with a thermal coating, such as a low emissivity coating <NUM>. In some embodiments, the inner surface <NUM> of the inner pane <NUM> may also be coated with a low emissivity coating <NUM>. The low emissivity coatings selected for the inner surface <NUM> and the inner surface <NUM> may be the same or different. Combinations of coatings may also be used, depending upon the desired thermal performance and end use of the insulated glass unit. Suitable low emissivity coatings are described above in connection with the <FIG> embodiment.

Gap spaces <NUM>, <NUM>, and <NUM> are, respectively, defined between the outer glass pane <NUM> and the central glass pane <NUM>, between the two central glass panes <NUM> and <NUM>, and between the central glass pane <NUM> and the inner glass pane <NUM>. Each of the gap spaces can be sealed with a sealing assembly, as known in the art, and filled with an inert gas, air, or a mixture of inert gas and air. Suitable inert gases include, for example, argon, krypton, and xenon.

To minimize or prevent the central glass panes from bowing, at least one channel or opening can be provided in each of the central panes <NUM> and <NUM> to allow contact between gases in the gap spaces, thereby removing the potential for differential pressures. In some examples, the channel is provided by changing the shape of the outer perimeter of the central panes, such as by clipping at least one corner of each of the central panes. The clipped corners can be the same corner for each central pane or can be different corners.

The thickness of the gap spaces <NUM>, <NUM> and <NUM> can be varied and can range from about <NUM> to about <NUM>. In some embodiments, the thickness of the gap spaces <NUM>, <NUM>, and/or <NUM> can be different. The total thickness of the four pane embodiment of the insulated glass unit <NUM> is about <NUM> or less, preferably about <NUM> or less, but can be at least about <NUM>. Desirable low U-values can be obtained when the gap spaces are in the range of about <NUM> to about <NUM> and the total thickness of the insulated glass unit is about <NUM> to about <NUM>.

In one or more embodiments, any one or more of the glass panes may form part of a display (e.g., LCD display), provide thermal insulation, form a back light unit (BLU), form a touch-enabled surface and combinations thereof. <FIG> illustrates an embodiment that is similar to the example not according to the invention shown in <FIG> except that the insulated glass unit <NUM> comprises four glass panes where at least one of the glass panes forms part of a display unit, and a touch-enabled surface. As shown in <FIG>, the insulated glass unit <NUM> includes an outer glass pane <NUM>, an inner glass pane <NUM>, and two central glass panes <NUM> and <NUM> intermediate the outer glass pane <NUM> and the inner glass pane <NUM>. Gap spaces <NUM> and 254are, respectively, defined between the inner glass pane <NUM> and the central glass pane <NUM>, and between the two central glass panes <NUM> and <NUM>. Each of the gap spaces can be sealed with a sealing assembly, as known in the art, and filled with an inert gas, air, or a mixture of inert gas and air. Suitable inert gases include, for example, argon, krypton, and xenon.

In the embodiment shown, there is no gap space between central glass pane <NUM> and the outer glass pane <NUM> and, instead, the central glass pane <NUM> and the outer glass pane <NUM> form part of an LCD transparent display <NUM>. In the embodiment shown, the outer glass pane <NUM> also includes a touch-enabled surface and may include a touch foil <NUM> or other structure providing touch functionality disposed on a surface thereof (e.g., inner surface <NUM>). The inner glass pane <NUM> includes an inner surface <NUM>, which may optionally include a coating (e.g., a low emissivity coating or other thermally insulative coating <NUM>).

It should be noted that the inner glass pane <NUM> may form part of the LCD display and the touch-enabled surface. In one or more examples, the inner glass pane <NUM> and/or the outer glass pane <NUM> may be a thin glass pane as described herein, which may optionally be chemically strengthened. The central glass pane <NUM> may include a thin or thick glass pane, which may be optionally chemically strengthened. The central glass pane <NUM> may optionally include a thermally insulative coating. The central glass pane <NUM>, which forms part of the LCD display <NUM> may provide a back light unit. In some examples, the central glass pane <NUM> may include a waveguide. The waveguide may be utilized to provide a backlight.

<FIG> illustrates an embodiment that is similar to the embodiment shown in <FIG> except that the insulated glass unit <NUM> comprises an inner (cold) surface <NUM>, an outer (warm) surface <NUM> and three glass panes where at least one of the glass panes forms part of a display unit, and a touch-enabled surface. As shown in <FIG>, the insulated glass unit <NUM> includes an outer glass pane <NUM>, an inner glass pane <NUM>, and a central glass pane <NUM> intermediate the outer glass pane <NUM> and the inner glass pane <NUM>. Gap spaces <NUM> and <NUM> are, respectively, defined between the inner glass pane <NUM> and the central glass pane <NUM>, and between the central glass pane <NUM> and the outer glass pane <NUM>. Each of the gap spaces is sealed with a sealing assembly, as known in the art, and filled with an inert gas, air, or a mixture of inert gas and air. Suitable inert gases include, for example, argon, krypton, and xenon.

In the embodiment shown, there is a gap space <NUM> between central glass pane <NUM> and the outer glass pane <NUM>, even though the outer glass pane <NUM> forms part of an LCD transparent display <NUM>. It should be understood that while the embodiments illustrated have been shown with two or more gap spaces and including a display, the claims appended herewith should not be so limited as exemplary embodiments can include an IGU with a single gap and an electronic display. Accordingly, in some embodiments, a single gap space may be utilized, in combination with an electronic display. For example, in <FIG>, the gap space <NUM> may be eliminated and only a single gap space (<NUM>) may be present, with central glass pane <NUM> and outer glass pane <NUM> forming at least part of an electronic display.

In the embodiment shown, the outer glass pane <NUM> also includes a touch-enabled surface and may include a touch foil <NUM> or other structure providing touch functionality disposed on a surface thereof (e.g., inner surface <NUM>). The inner glass pane <NUM> includes an inner surface <NUM>, which may optionally include a coating <NUM> (e.g., a low emissivity coating or other thermally insulative coating). It should be noted that the inner glass pane <NUM> may form part of the LCD display and the touch-enabled surface, instead of or in addition to the outer glass pane <NUM>.

Claim 1:
An insulated glass unit (<NUM>) comprising:
a first glass pane (<NUM>) having an outer surface (<NUM>) and an inner surface (<NUM>);
a second glass pane (<NUM>) having an outer surface (<NUM>) and an inner surface (<NUM>), wherein the second glass pane (<NUM>) comprises a laminate structure; wherein any one or more of the first glass pane (<NUM>) and the second glass pane (<NUM>) is fusion-formed and has a thickness of <NUM> to not greater than <NUM>,
a third glass pane (<NUM>) disposed between the first and second glass panes (<NUM>, <NUM>), wherein the third glass pane (<NUM>) is fusion-formed and comprises a thickness of at least <NUM> to not greater than <NUM>,
a first sealed gap space defined between the first glass pane (<NUM>) and the second glass pane (<NUM>);
a second sealed gap space (<NUM>) defined between the first glass pane (<NUM>) and the third glass pane (<NUM>);
a third sealed gap space (<NUM>) defined between the second glass pane (<NUM>) and the third glass pane (<NUM>); wherein the sealed gap spaces are filled with an inert gas; and
wherein the third glass pane (<NUM>) has a channel or opening allowing the gas in the second sealed gap space (<NUM>) to contact the gas in the third sealed gap space (<NUM>).