Equipment for Forming 3D Features in a Device & Testing the Strength of Sapphire Revealed in Apple Patents
It's always fun to read about new consumer oriented inventions like a wireless charging device that shows a user that charging has begun by levitating an Apple device like an iPhone – or to discover that Apple has begun researching new form factors like a scrollable iPhone. But for some of us, learning about some of the behind the scenes processes that Apple is working on to perfect future products is just as fascinating. Last week the U.S. Patent Office revealed two interesting inventions by Apple. The first covers a new testing device for artificially grown corundum to form sapphire parts and housings while the second invention involves forming recessed features in a ceramic or sapphire component for an electronic device like logos or device housing textures.
Flexural Testing Apparatus
The first patent in this report relates generally to a material testing apparatus and, more particularly, to a flexural testing apparatus designed to stress a material to analyze physical and/or mechanical properties of the stressed material and a method of testing the material.
Apple notes that in order to ensure all sapphire material used to form components of the electronic device meet quality control standards and/or will function substantially similar between each individual device, the sapphire material may undergo conventional material testing processes. Such material testing processes may include ring-on-ring material testing or ball-on-ring material testing. These tests may apply a force to the sapphire material until the material flexes or breaks.
However, because of the unique chemical or physical characteristics of sapphire material and/or the discrepancies that may form in the material, conventional material testing processes may be inadequate. For example, the ring-on-ring and ball-on-ring material testing processes may only form a contact area on the tested sapphire material where the ring or ball contact the material. As such, the ring or ball may only apply a force in the contact area of the sapphire material during the test. This may result in inaccurate measurements of force required to flex and/or break the sapphire; during testing, the ring or ball may not contact areas of the sapphire in which faults or flaws exist and so the effect of such faults or flaws may not be determined by conventional tests.
Apple's patent FIG. 1 noted below shows us an illustrative perspective view of a sapphire structure #100 that may be a wafer of artificially grown corundum to be further processed and used in an electronic device.
The artificially grown corundum used to form the sapphire structure may be grown using any conventional growth process including, but not limited to: hydrothermal growth; vertical horizontal gradient freezing ("VHGF"); edge-defined film-fed growth ("EFG"); horizontal moving growth (e.g., Bridgman growth); and Kyropoulos growth.
The sapphire structure may be singulated or otherwise formed into individual pieces or components that may be utilized as a variety of components of many, distinct electronic devices. In non-limiting examples, processed components formed from the sapphire structure may include cover glasses, buttons, caps, housings or enclosures and the like for an electronic device.
The sample electronic devices whose housing may use sapphire take the form of a tablet computing device, phone, personal digital assistant, computer, wearable electronic device (e.g., smart watch), digital music player and so on.
Apple's patent FIG. 8 noted above depicts a stress-graph illustrating the actual stress experienced by the sapphire structure of FIG. 1 to deflect the sapphire structure to a maximum, calculated flexion point.
It appears that Apple is determined to continue their work with artificially grown corundum / sapphire despite ending their relationship with GT Advanced Technologies. Other patents surfacing after the GTAT breakup include laser polishing ceramic and sapphire and a laser system to color sapphire materials for a future iPhone.
Apple's patent application was filed back in Q3 2015. To review the details about this invention, click here. Considering that this is a patent application, the timing of such a product to market is unknown at this time. The inventors on this patent are Dale Memering, Manager of Product Design Materials and product design engineer Victor Luzzato.
Method for Forming a 3D Feature in a Cover Surface
Materials such as metal or glass, sapphire, or other ceramics may be finished using a variety of different abrading or other material removal processes. For example, polishing may rub a surface of a part using a tool (such as a bristle brush) to achieve a particular surface finish. In many cases, polishing is performed on flat or planar surfaces using flat rotatory brushes. Such a process may work well for polishing flat surfaces, but may not create as uniform a polished finish for three-dimensional features.
Apple's invention relates to finishing three-dimensional features using abrading and/or other processes that remove material. More particularly, the present embodiments relate to forming recessed features in a ceramic component for an electronic device.
A three-dimensional feature may be formed in a surface of a component. Material may be removed from the component by rotating an abrading tool about a first axis. While the abrading tool is rotated, the component may be rotated on a second axis. The second axis may be transverse to the first axis and may run through a center of the three-dimensional feature. The abrading tool may correspond to the three-dimensional feature.
For example, the abrading tool may be configured to contact an entirety of an exterior of the three-dimensional feature during the removal operation, fill the three-dimensional feature during the removal operation, and/or have a shape that corresponds to the shape of the three-dimensional feature in two planes that are normal to each other. In this way, material may be removed from portions of the three-dimensional feature in a first direction and subsequently material may be removed from the same portions in one or more additional directions. This may prevent, reduce, and/or ameliorate streaks, brush lines or other artifacts related to the material removal.
In some examples, the operation of removing the material may form the three-dimensional feature in a flat area of the surface. In various examples, the three-dimensional feature may have a concave dome shape and the abrading tool may have a convex shape matching the concave dome shape. In some examples, the three-dimensional feature may be a dish.
Apple's patent application was originally filed on September 2, 2015. To review the details behind Apple's invention, click here. The inventors listed for this invention are Jeremy Franklin, Product Design Manager who came from MIT, and Kristina Babiarz, Product Design Engineer.
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