The proliferation of low power, large capacity, small form factor, external hard disk drives into consumer electronic products will be the largest growth areas over the next few years according to market analysts. These go-anywhere, high-capacity and ultra-low power ultra-mobile storage devices are ideal for capturing, viewing, archiving, sharing and managing digital audio and video files easily. Camcorders, PDA’s, audio and video players, televisions, automobiles and personal video recorders are among the emerging applications for these new storage platforms. To meet this demand, a new paradigm has emerged for the design and manufacturing of mobile hard disk storage devices that combine high storage capacity and performance with ultra-low power consumption and are able to operate in a wide range of environments including space and under water.
This paradigm is:
“Mobile Hermetically Sealed Storage”
High Performance and high power consumption are synonymous with Hard Disk Drives (HDDs) in part, due to the viscous drag of the surrounding air on the magnetic disks during high speed angular rotation. This drag is directly proportional to the air density of the gas surrounding the disks and can lead to excessively high temperatures within the HDD.
In addition, air contains oxygen and water, both of which are detrimental to the long term reliability of the drive. The disks, magnetic heads and permanent magnets react with oxygen and must be protected in some way. The water in the air limits the operating temperature of the drive to above freezing which is unacceptable for drives that must be mobile and operate over a wide range of temperatures.
The last, but by no means the least, is the “flying height” of the magnetic head that records and reads data to and from the magnetic disk. This has been identified as the major problem confronting the trend of increasing areal density toward and beyond 1 terabit per square inch.
To resolve these problems, we will place the head/disk assembly in hermetically sealed chambers, and replace the air with Nitrogen at a pressure between 0.1 and 0.2 atmospheres (1.0 to 3.0 psi). This accomplishes the following.
1. Aerodynamic power consumption reduced by ratio of gas pressure in Head Disk Assembly (HDA) and atmospheric pressure (PHDA/Pa).
2. Flying height reduced by ratio of gas pressure in HDA to atmospheric pressure
3. Contact start/stop becomes possible again with glass substrates thus avoiding the “ramp” load/unload methods used into today’s drives.
4. Since the inert gas is “water” free, the operation temperature range can be extended to below freezing temperatures
The drives are manufactured in accordance with US Patent 7,643,244 entitled “Integrated Battery Powered Hard Disk Drive” in which the key and enabling component of the drive is the Ceramic Base which was manufactured by processes and equipment common to the semiconductor industry.