MEMS (Micro-Electro-Mechanical Systems) are becoming more prevalent in the electronics we use today and will play an even bigger role in technology being developed for the near future. The tiny nano-sized (1 to 100 micrometers in size) devices usually incorporate its own microprocessor along with several components that are designed for interaction in its immediate surroundings. They can be found in mobile devices (smartphones and tablets) as sensors such as accelerometers, which can also be found in some game controllers as well, such as Nintendo’s Wii-mote. We can also see them being used for piezoelectric devices (found in inkjet printers and energy collection systems), displays (interferometric modulator display) for mobile devices and even biosensors and chemo-sensors used in the medical fields. As with all electronics, they require some level of protection and as devices continue to shrink in size and become mobile, that protection needs to increase as well. Electronics companies routinely perform a series of ‘damage’ tests (drop testing and simulation) on their products to see how robust they are and then adjust the design accordingly to lessen that damage. Typically, these include a robust protective casing usually made of polymer, rubber or both, which protects electronics from minor impacts.
Uniformity and the ability to get at those "hard to reach places" is key to Parylene coating. The difference between the correct way and good enough. (via Diamond MT)
Otterbox, Body Glove and LifeProof (among a host of others) all provide cases for mobile devices, which usually incorporate a screen-protector, rubberized shroud along with a polymer outer casing to lessen impact usually dropped from just a few feet. While impact resistance is great for mobile devices and ruggedized laptops and notebooks (military grade), they don’t really protect those devices and their delicate electronics from the elements or other adverse conditions. Some companies have turned to protecting those electronics from the inside rather than focusing on the outside, in the form of conformal coating. The coating (silicone, epoxy, acrylic, polyurethane, etc.) is applied directly to the electronics PCB board along with the components connected to it, including embedded MEMS devices, in order to protect the device from moisture, dust, chemicals as well as temperature extremes (electronics have temperature threshold limits before the malfunction). There are many popular conformal coating solutions on the market today including offerings, from NeverWet and Liquipel, that offer protection for mobile and electronic devices. However, the results can vary and are sometimes ‘spotty’ at best.
When it comes to protective coatings for devices on a nano-scale such as sensors, actuators and mechanical structures, the coating needs to be impermeable against contaminants at the submicron levels. This is where Diamond-MT’s Parylene conformal coating shines, as the material offers superior protective properties than that of its competitors. The material is applied by vapor deposition inside of a vacuum and therefore can penetrate crevices down to an astonishing 0.01mm. This results in a tighter-fitting conformal layer than those applied by other methods such as spraying or dipping, which can result in an uneven layer and thereby negate the protective properties. The material is hydrophobic, making it water and liquid repellant on a very small scale free of pinholes. Parylene also features a low dielectric constant (electric insulator) as well as low current leakage (electrostatic lines are not impeded), which makes it ideal for incredible small electronics such as MEMS. Temperature almost becomes a non-issue using Parylene, as the material is able to retain its protective properties without degradation for 10-years at 800C and has a temperature threshold of an astounding 2000C! The polymer applies clear and stays clear while providing protection against UV rays that can damage sensitive electronics and optics. It’s no wonder that Diamond-MT has been coating sensitive MEMS-based electronics for the last ten years, as their Parylene coating is far superior to the other conformal coatings currently on the market.
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