News Column

"Mobile Electronic Device Comprising an Ultrathin Sapphire Cover Plate" in Patent Application Approval Process

June 5, 2014

By a News Reporter-Staff News Editor at Politics & Government Week -- A patent application by the inventors Zahler, James M. (Winchester, MA); Petti, Christopher J. (Mountain View, CA), filed on November 14, 2013, was made available online on May 22, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application is assigned to Gtat Corporation.

The following quote was obtained by the news editors from the background information supplied by the inventors: "The present invention relates to a mobile electronic device comprising a sapphire cover plate.

"There are many types of mobile electronic devices currently available which include a display window assembly that is at least partially transparent. These include, for example, handheld electronic devices such media players, mobile telephones (cell phones), personal data assistants (PDAs), pagers, and laptop computers and notebooks. The display screen assembly may include multiple component layers, such as, for example, a visual display layer such as a liquid crystal display (LCD), a touch sensitive layer for user input, and at least one outer cover layer used to protect the visual display. Each of these layers are typically laminated or bonded together.

"Many of the mobile electronic devices used today are subjected to excessive mechanical and/or chemical damage, particularly from careless handling and/or dropping, from contact of the screen with items such as keys in a user's pocket or purse, or from frequent touch screen usage. For example, the touch screen surface and interfaces of smartphones and PDAs can become damaged by abrasions that scratch and pit the physical user interface, and these imperfections can act as stress concentration sites making the screen and/or underlying components more susceptible to fracture in the event of mechanical or other shock. Additionally, oil from the use's skin or other debris can coat the surface and may further facilitate the degradation of the device. Such abrasion and chemical action can cause a reduction in the visual clarity of the underlying electronic display components, thus potentially impeding the use and enjoyment of the device and limiting its lifetime.

"Various methods and materials have been used in order to increase the durability of the display windows of mobile electronic devices. For example, polymeric coatings or layers can be applied to the touch screen surface in order to provide a barrier against degradation. However, such layers can interfere with the visual clarity of the underlying electronic display as well as interfere with the touch screen sensitivity. Furthermore, as the coating materials are often also soft, they can themselves become easily damaged, requiring periodic replacement or limiting the lifetime of the device.

"Another common approach is to use more highly chemically and scratch resistant materials as the outer surface of the display window. For example, touch sensitive screens of some mobile devices may include a layer of chemically-strengthened alkali aluminosilicate glass, with potassium ions replacing sodium ions for enhanced hardness, such as the material referred to as 'gorilla glass' available from Corning. However, even this type of glass can be scratched by many harder materials, and, further, as a glass, is prone to brittle failure or shattering. Sapphire has also been suggested and used as a material for either the outer layer of the display assembly or as a separate protective sheet to be applied over the display window. However, sapphire is relatively expensive, particularly at the currently available thicknesses, and is not readily available as an ultrathin layer.

"Thus, while materials are available which can enable the display of a mobile electronic device to be relatively resistant to damage, there remains a need in the industry for materials and methods for providing improved mechanical toughness and scratch resistance without reducing transmittance."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "The present invention relates to an electronic device comprising a cover plate having at least one transparent display region. The cover plate comprises one or more sapphire layers having a thickness of less than 50 microns, such as less than 30 microns, less than 25 microns, and less than 15 microns. The cover plate may be a single, free-standing sapphire layer or may comprise more than one sapphire layer, each having a thickness of less than 50 microns such as less than 30 microns. The cover plate can be affixed to the surface of a display element of the electronic device, or it may be a protective layer that is removably positioned or placed on top of the display element. Preferably the thin sapphire layer is the front surface of the cover plate. The present invention further relates to the cover plate comprising one or more sapphire layers having a thickness of less than 50 microns, as well as to the ultrathin sapphire layer.

"The present invention further relates to a method of preparing a cover plate of an electronic device, and preferably the cover plate of the present invention is prepared by this method. In particular, the method comprises the steps of providing a donor body of sapphire, implanting through the top surface of the donor body with an ion dosage to form a cleave plane beneath the top surface, exfoliating the sapphire layer from the donor body along the cleave plane, and forming the cover plate comprising this sapphire layer, which has a thickness of less than 50 microns. Preferably, the ion dosage comprises hydrogen or helium ions.

"It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the present invention, as claimed.


"FIG. 1, FIG. 2, and FIG. 3 show various embodiments of the cover plate of the electronic device of the present invention."

URL and more information on this patent application, see: Zahler, James M.; Petti, Christopher J. Mobile Electronic Device Comprising an Ultrathin Sapphire Cover Plate. Filed November 14, 2013 and posted May 22, 2014. Patent URL:

Keywords for this news article include: Gtat Corporation.

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Source: Politics & Government Week

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