On May 22, 2014, the US Patent & Trademark Office published a patent application from Apple that reveals more details relating to sapphire cover glass for future iDevices. Today, Apple's Home Button uses laser cut Sapphire. In the future, it may simply be an extension of the cover glass that will also cover any bezel construction. The use of sapphire cover glass may extend to many products including the iPhone, an iMac, a MacBook (Pro or Air), ultraportable computers and monitor display devices.

Apple's Patent Background

Electronic devices generally include a variety of different display and cover components, including front and back glasses (or cover glasses), display windows, touch screens, track pads, camera and lens covers, and other internal and external cover components where optical features, durability and reliability are design issues. In use, these components are subject to a wide range of different environmental effects, including physical and electrical contact, temperature extremes, scratching, and impact.

These effects raise a number of design issues, particularly where internal and external components are subject to different combinations of environmental conditions and performance requirements. Associated design and engineering considerations include tradeoffs between shock and impact resistance, machinability, temperature stability, and thermal and electromagnetic properties including resistance, conductance, and permeability.

Apple's Invention Relates to Methods of Making Sapphire based Display Cover Glass

Apple's patent generally relates to display and cover glass components for electronic devices. In particular, the invention relates to laminated materials suitable for use in display and cover glass components for electronic devices, including, but not limited to, cellular phones, tablet computers, personal computers, personal digital assistants, media players, and other stationary and portable electronic devices.

Apple's patent relates to cover glass and display components for electronic devices, methods of making the cover glass, and electronic devices incorporating the cover glass and display components.





Apple notes that the cover glasses 12A and 12B above representing both the back and front cover glass of an iPhone may also include or accommodate additional features, including, but not limited to, additional control features 20 (e.g., a home button or other control device), audio features 22 (e.g., a speaker or microphone), sensors 24A and 24B (e.g., cameras or infrared sensors), and lighting or indicator features 26 (e.g., a flash unit, light emitting diode or other indicator, display or illumination device). Depending on design requirements, additional cover glass components may be provided for one or more of these features, for example a separate lens cover glass element 12C for camera 24B, as provided within back cover glass 12B.

In various examples and embodiments, the cover glass includes a plurality of layers of substantially single-crystal sapphire, each of the layers having a substantially single crystal plane orientation, with adjacent layers having different orientations. One or more interface layers are defined between adjacent sapphire layers, bonding the layers together. A display window is defined in the cover glass, and configured for viewing the electronic display through the sapphire and interface layers.

Depending on configuration, the adjacent layers of substantially single crystal sapphire may have substantially orthogonal crystal plane orientations, for example alternating A and C plane orientations defined substantially along the one or more interface layers.

One or more of the sapphire layers may also include a metal component selected for physical properties including color, hardness, thermal or electrical conductivity and resistivity, and magnetic permeability.

The cover glass may include a display window layer comprising substantially opaque border portions and a substantially transparent window portion configured to define the display window in the cover glass. The display window layer can be provided between two of the layers of substantially single-crystal sapphire material, or in a top or bottom layer of the cover glass.

The one or more interface layers may define adhesive bonds or hydrogen bonds between the adjacent sapphire layers. Alternatively, the one or more interface layers may be fused together across the one or more interface layers, for example by fusing a polycrystalline or amorphous aluminum oxide material between the adjacent sapphire layers. Depending on manufacturing method, the cover glass can be formed by compressively loading the adjacent sapphire layers during thermal fusion, for example at a fusion temperature between about 2000.degree. C. and about 2100.degree. C.

Apple further notes that a substantially transparent display window is defined in the front glass, and configured for viewing the display through the plurality of sapphire layers. For example, the device may include a display layer disposed between two of the sapphire layers, where the display layer includes substantially opaque side portions and a substantially transparent window portion to define the display window in the front glass.

The sapphire based cover glass could apply to a mobile telephone and computing devices with media player capabilities, remote controls and game players, global positioning and telecommunications devices, and laptop, desktop, notebook, handheld or ultraportable computer and monitor display devices.

The cover glass incorporates a laminated sapphire, crystalline aluminum oxide or sapphire glass construction, as configured for improved hardness, durability, impact and scratch resistance or other performance features selected for the particular characteristics of electronic device #10.

Particular examples of cover glass include, but are not limited to, front glass 12A, back glass 12B, specialty (e.g., camera or lens) cover glass or a glass insert, inset or inlay element.

Depending on embodiment, the cover glass may include display window and one or more additional control features including the Home Button #20 as well as volume, ringer, and hold switches, buttons and other control features.

In Apple's patent FIG. 7A noted below we're able to see sapphire layers 50A-50D that could also be doped or implanted with a range of different materials to provide desired physical properties, including, but not limited to, color, density, hardness, thermal or electrical conductivity and resistivity, and magnetic permeability or reluctance.

In particular, any one or more of single-crystal sapphire layers 50A-50D may include one or more iron, titanium, chromium, copper, magnesium or other metal components, dopants, or impurities, in order to provide a desired tint or color cast, such as red, orange, yellow, green, blue, violet or purple, or a combination thereof. Where chromium impurities are present, for example, sapphire layers 50A-50D may also be referred to a ruby layers, and the cover glass may be referred to as a ruby glass or ruby cover glass component.

Patent Credits

Apple credits Kelvin Kwong as the sole inventor of patent application 20140139978 which was originally filed in Q4 2012. Considering that this is a patent application, the timing of such a product to market is unknown at this time.

A Second Sapphire Related Patent

In a secondary patent filing under number 20140138221 we see patent FIGS 5A and 5B as noted below. Apple's patent FIG. 5A is a cross-sectional view of control mechanism 50 (Apple's Home Button) for an electronic device. The control mechanism includes a single crystal aluminum oxide (sapphire) control button or switch control member #52, positioned within control aperture #54, as defined in housing or cover component #56. The housing may comprise a bottom, top, front, side or back housing or a front or back cover glass. The control mechanism may comprise control member #52 for a pushbutton, rocker, or slide switch control mechanism.

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