Apple recently quietly filed a United States patent application for a special, ultra-thin hydrophobic coating that when applied to electronic components would protect them from water damage if sprayed or submerged.
The appearance of the application is intriguing, particularly because that then raises questions about how Apple might use such a coating. Perhaps the company is experimenting with such a process to use in its iPhones, iPads and other devices to help protect them from spills and accidental drops into puddles, sinks and other water hazards, but at this point it's not certain what the plans are for the research.
The hydrophobic coating is a different approach to making something waterproof or water-resistant. Usually, products include rubber or other flexible membranes that are sandwiched between hard metal, plastic of other parts to seal moisture out of a product by acting as a barrier. That's how many waterproof or water-resistant products are built today.
The hydrophobic coating is innovative, according to the patent application, because it would be applied to components that would essentially repel any invading water. By using such a coating, the case or shell of a product would not have to be built to seal out moisture with special seals and membranes because the delicate electronics would instead be coated and protected on their own.
Today's Apple devices are not waterproof or water-resistant, but some products from competitors include such features. Samsung's Galaxy S5 smartphone last year included special sealing to make it water-resistant, while Sony's Xperia Z2 smartphone boasted a waterproof housing when it was unveiled in February 2014, according to earlier eWEEK reports.
Apple did not immediately respond on March 9 to an email inquiry seeking more details about the patent application and its potential future use in the company's products.
The patent application, which was filed on March 5, covers "methods for shielding electronic components from water" via a hydrophobic coating that can be applied by a plasma-assisted chemical vapor deposition (PACVD) process to a completed circuit board, according to the document.
"Frequently, a fully assembled circuit board can have various components such as electromagnetic interference (EMI) shields which cover water sensitive electronics," the application states. "A method is disclosed for perforating portions of the EMI shields that overlay the water sensitive electronics. Methods of sealing board to board connectors are also disclosed. In one embodiment solder leads of the board to board connectors can be covered by a silicone seal."
The waterproofing methods using hydrophobic coatings might also include the use of special tapes coated with a polyimide film to help seal the components, the application states. The
applied hydrophobic conformal coatings would be between about 1 to 3 microns thick, according to the documentation. The sealing methods also apply to preventing water from leaking into devices through small openings used for charging, earphones and other attachments.
An original patent application related to the technology was filed on Sept. 4, 2013, and the latest application expands the patent with more information and research.
"Immersing electronic devices in water generally has predictably negative results," the latest application states. "Through testing it has been determined that high voltage power components are more likely to short or malfunction after only brief exposure to liquids or moisture. More specifically, exposed metal areas having high voltage differentials in close proximity can easily experience short circuit events when corrosion or water immersion bridges the gap between such areas. By providing an insulating layer or barrier around these highly susceptible parts, water resistance can be substantially increased without obscuring functional openings leading into a device housing of a particular electronic device."
That's where the hydrophobic coatings can help, the application states. Using a plasma-assisted chemical vapor deposition (PACVD) process, the hydrophobic coatings can be bonded to the components, thereby protecting them from water.
"Additionally, when the component is in a fully assembled state, the conformal coating can thoroughly cover substantially all exposed surfaces of the assembled component in a single deposition operation," the application continued.