Embodiments generally relate to electronic display assemblies.
Electronic display assemblies are known to be very thin and over time these displays can warp outwardly, towards a transparent protective plate or glass assembly. If the display contacts the protective plate, it can produce visual anomalies in the image and may even wet bond the display surface to the protective plate.
Exemplary embodiments disclosed herein provide a glass assembly having a bottom sheet of glass which is substantially planar, bonded to a top sheet of glass which is substantially concave. A layer of adhesive is preferably interposed between the bottom and top sheets of glass. In an exemplary embodiment, the amount of adhesive used would be less than the amount required to hold both sheets of glass in a parallel planar arrangement. The layer of adhesive may be contained between the two sheets of glass by a perimeter of adhesive tape, also interposed between the top and bottom sheets of glass. The assembly can be used with an electronic display where the display is positioned adjacent to the top sheet of glass, and due to its concavity, the electronic display can bow towards the top sheet of glass without actually contacting the glass.
Exemplary embodiments disclosed herein provide a glass assembly having a bottom sheet of glass which is substantially planar, bonded to a top sheet of glass which is substantially concave. A layer of adhesive is preferably interposed between the bottom and top sheets of glass. In an exemplary embodiment, the amount of adhesive used would be less than the amount required to hold both sheets of glass in a parallel planar arrangement. The layer of adhesive may be contained between the two sheets of glass by a perimeter of adhesive tape, also interposed between the top and bottom sheets of glass. The assembly can be used with an electronic display where the display is positioned adjacent to the top sheet of glass, and due to its concavity, the electronic display can bow towards the top sheet of glass without actually contacting the glass.
A better understanding of an exemplary embodiment will be obtained from a reading of the following detailed description and the accompanying drawings wherein identical reference characters refer to identical parts and in which:
The invention is described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Embodiments of the invention are described herein with reference to illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of the invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The display subassembly 375 preferably contains a ledge 376 which runs around the perimeter of the display 300. The front glass assembly 150 is preferably sandwiched in between the ledge 376 and a corresponding ledge 121 on the frame 120, which should be sized as small as possible so that each display assembly 100 could be mounted as close as possible to one another, giving the appearance of a large seamless display. In some embodiments, the front glass assembly 16 is a single piece of glass. However, in an exemplary embodiment the front glass assembly comprises a front sheet of glass 16 which is laminated to a rear sheet of glass 15 with a layer of adhesive 18, preferably an optical adhesive.
There is preferably a small gap 350 defined between the rear surface of the glass assembly 150 and the front surface of the electronic display 300. It has been found that in some applications the electronic display 300 is a relatively thin and flexible, and over time can sag or bow outward. This phenomenon is illustrated in
An exemplary anti-reflective glass could be Pilkington OptiView™ glass which is commercially available from Pilkington Building and Specialty Glass Products of Toledo, Ohio (herein ‘OptiView glass’). www.pilkington.com The document “Pilkington OptiView™ Anti-Reflective Glass,” Form No. 4483, is herein incorporated by reference in its entirety.
It should be noted, that any glass which meets the performance characteristics set by the OptiView glass would fall within the exemplary embodiments. OptiView glass was simply selected for exemplary purposes. Chart 1 provides typical performance characteristics for two pieces of glass, each with an anti-reflective pyrolytic coating on one side, where the two pieces of glass are laminated or bonded together. Currently, Pilkington Glass does not provide this dual-layered glass with two pyrolytic coatings. Users must purchase single pieces of glass with a single pyrolytic coating and laminate or bond the pieces themselves. See the Chart 1 Notes for specifics.
Adhesive 18 is used to bond the glass layers 15 and 16. An optical adhesive is preferably used to bond the glass together. Even more preferably, an index-matched optical adhesive may be used. Exemplary embodiments may utilize Uvecol® S adhesive, commercially available from Cytec Surface Specialties, Inc. of Smyrna, Ga. www.cytec.com. The document “Uvecol® S UV Curable Glass Laminating System,” May 4, 2006, is herein incorporated by reference in its entirety. Embodiments may alternatively utilize Uvecol® A adhesive. In an exemplary embodiment, the glass layers 15 and 16 are laminated together by UV-curing the adhesive 18.
Very High Bond (VHB) tape 17 may be used to seal around the edges of the glass 15 and 16. In an exemplary embodiment, the VHB tape 17 would be a clear acrylic tape in a thickness between 0.5 mm and 3.0 mm.
An exemplary front glass assembly for small displays may utilize glass panels of thickness between 3.0-3.5 mm and VHB tape of thickness between 0.8-1.2 mm. An exemplary front glass assembly for larger displays may utilize glass panels of thickness between 6.0-6.5 mm and VHB tape of thickness between 1.0-1.5 mm.
However, in an exemplary embodiment of the special bonding method, a smaller amount of adhesive 18 is purposefully used so that during the curing process the rear sheet 15 will bow inwards towards the front sheet 16.
As can be observed, the rear sheet 15 has bowed inwards towards the front sheet 16, which now provides additional space for the electronic display 300 to bow forwards without contacting the rear surface of the rear sheet 15. The precise amount of bowing can be controlled based on the thickness of the VHB tape 17 and the reduction in the amount of adhesive 18 used. In some embodiments, the amount of bowing can be between 0.5 mm and 2 mm, but again this could be any amount that is desired. While it is preferable for the front sheet 16 to remain flat so that the resulting glass assembly 150, when viewed from the perspective of a viewer of the electronic display, the glass assembly 150 does not appear warped or cause any optical deficiencies as the front sheet 16 is flat, or substantially planar.
When oriented in this fashion (where the rear sheet 15 is on top and the front sheet 16 is on the bottom) it can be said that the rear sheet 15 transforms from a planar sheet to a concave sheet during the adhesive curing process. Alternatively, the cross-section, taken near the center of the resulting assembly as shown in
Another way of describing the rear sheet from an exemplary embodiment would be to describe it as a three-dimensional catenary, produced by supporting only the perimeter of the rear sheet and allowing the center to bow due to (1) the natural weight of the sheet due to gravity and (2) forces due to the curing of the adhesive and the fact that the amount of adhesive used is preferably less than what would be required to produce a substantially planar rear sheet. In an exemplary embodiment, the amount of adhesive used may be reduced by 5%-25% when compared to the amount of adhesive required to produce a planar rear sheet with no excess adhesive wasted. The amount of adhesive could be measured by volume or weight.
Having shown and described a preferred embodiment of the invention, those skilled in the art will realize that many variations and modifications may be made to affect the described invention and still be within the scope of the claimed invention. Additionally, many of the elements indicated above may be altered or replaced by different elements which will provide the same result and fall within the spirit of the claimed invention. It is the intention, therefore, to limit the invention only as indicated by the scope of the claims.
This application claims priority to U.S. Provisional Application No. 61/786,984, filed on Mar. 15, 2013 and herein incorporated by reference in its entirety.
Number | Date | Country | |
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61786984 | Mar 2013 | US |