Patent Application
20080013206
The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention:
The drawings referred to in this description should not be understood as being drawn to scale except if specifically noted.
Reference will now be made in detail to various embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with these embodiments, it will be understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. In other instances, well-known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the present invention.
There are several problems with the conventional air filter 172 as depicted in
Second, it is important that the actuator 140 be stable as the actuator is reading data or writing data. A measurement commonly known as tracks misregistration (TMR) is used for determining how far the read write head misses a track on a disk during a read or write operation. As can be seen, the more stable the actuator 140 is, the lower the TMR will be, and therefore data can be stored on a disk 112 at a higher density. However, since a conventional filter 172 causes turbulent air flow patterns, for example by causing too much turbulent air to pass by the actuator as described herein, the voice coil motor 150 has to work harder to keep the actuator 140 on track. This can result in a moderate increase in heat, for example, in a server farm with a hundred or more disk drives.
Third, the conventional filter 172 is typically limited in its ability to cleanup the environment inside of the disk drive 110. For example, the larger that the filter 172 is the better and the more quickly it 172 can clean up the environment inside of the disk drive 110. However, the space inside of a disk drive 110 is limited therefore the size of the filter 172 is limited. Further, the larger the filter obstruction of the bypass channel the harder the disk drive 110 will have to work to force the air through the filter 172. It has been found that the time constant effectiveness of a conventional filter 172 is limited to approximately 60 to 90 seconds due to the size restrictions of the conventional filter 172.
Therefore, there is a need for a disk drive filtering system that reduces the obstruction of air flow through a bypass channel associated with a disk drive and that does a better job of cleaning up the environment inside of the disk drive than the conventional filter 172. According to one embodiment, a filter is associated with a disk drive in a manner that the flow of air is substantially unobstructed, as will become more evident.
According to one embodiment, filter 200 is a pass-by filter because air can freely flow across the filter 200 rather than being forced through the filter 200. Therefore, as will become more evident, filter 200 can provide considerably more surface area for cleaning the environment.
Filter 200 can include a carrier 202, such as clean room paper. The filter 200 can have adhesive, such as pressure sensitive (PSA), on one or both sides. According to one embodiment, one of the adhesive sides can be used to attach the filter 200 to the disk drive. According to another embodiment, the filter 200 can be attached to the disk drive using slots or tabs instead of adhesive. Adhesive, slots and tabs are examples of holding structures that enable the filter to be attached to the disk drive.
Various filtering materials 204 such as material for filtering chemicals, electrostatic media and impact media can be associated with the filter 200. The impact media can be used for filtering relatively large particles that will collide into the filter 200. The electrostatic media can be used for filtering particles that are too small to cause collision. Typically electrostatic media has negative and positive charges. Therefore, the electrostatic media can attract negatively or positively charged particles that are too small to otherwise collide with the filter 200. Material for filtering chemicals, such as activated carbon, can filter chemical vapors such as hydrocarbons or fluorocarbons. The various filtering materials 204 can be attached to one of the adhesive sides of the filter 200 and the other adhesive side can be attached to the disk drive, as will become more evident. In another embodiment, various filtering materials 204 can be fused to the carrier 202 instead of using an adhesive.
In yet another embodiment, the filter 200 does not include a carrier 202, such as clean room paper. Instead the filtering materials 204 can be used to create the structure of the filter 200 for example by weaving the filtering materials together or by fusing the filtering materials together using heat and pressure. In still another embodiment, the filtering materials are fused together only at the outer edges so that the filter's middle is highly porous.
In contrast,
Portions of air 310 and 330 are filtered by the filters 200, for example, as the portions of air 310, 330 flow through or proximate to the filtering materials 204 associated with the filters 200. The filter free region 308 is disposed proximate to the pass-by filters 200. Another portion of air 320 is allowed to flow substantially unobstructed through the filter free region 308 that is disposed within the selective filtering region 302.
Although the portions of air 310, 320, 330 are depicted with straight arrows, air typically swirls around as it flows within a bypass channel 168. Therefore, one set of air particles maybe in the filter free region 302 at one point in time and then be in a filtering region 304 at another point in time. However, it should still be evident to one of ordinary skill in the art that various embodiments of the present invention provide for air flow that is substantially unobstructed.
Although
The air is not obstructed at position 174, as depicted in
The filters 200, according to one embodiment, can be attached to the bypass channel 168 in various ways so that the air does not have to flow through the filters 200. As depicted in
As already stated, the effectiveness of a filter to cleanup the environment inside of a disk drive is directly proportional to the size of the filter. Further, the space inside of a disk drive is limited. Therefore, the size of a conventional filter 172 as depicted in
All of, or a portion of, the embodiments described by flowchart 500 can be implemented using computer-readable and computer-executable instructions which reside, for example, in computer-usable media of a computer system or like device. As described above, certain processes and steps of the present invention are realized, in one embodiment, as a series of instructions (e.g., software program) that reside within computer readable memory of a computer system and are executed by the computer system. When executed, the instructions cause the computer system to implement the functionality of the present invention as described below.
In step 505, the process begins.
In step 510, a bypass channel is created for the disk drive. For example, a bypass channel 168 is created by creating an enclosure for the disk drive 400 with a shape that provides the bypass channel 168. Further, various components such as the voice coil motor 157, the motor hub assembly 150 and the disks 135 are assembled in the disk drive 400 in a manner that provides for the demarcation of the bypass channel 168. Air can flow 170 through the bypass channel 168.
In step 515, a pass-by filter is created. For example, assume that a filter 200 includes a carrier 202, such as clean room paper, has adhesive on both sides, and filtering materials 204 are attached to one of the adhesive sides.
In step 520, the pass-by filter can be associated with a selective filtering region within the bypass channel. For example, the other adhesive side of the filter 200 can be used to attach the filter to the bypass channel 168. Referring now to
In step 525, the process ends.
According to various embodiments of the present invention, pass-by filters can be used to allow air to flow substantially unobstructed through a bypass channel of a disk drive. Therefore, less heat is generated, the TMR is lowered so more data can be stored on a disk drive, and the environment of a disk drive can be cleaned more quickly and remain cleaner, among other things, than is the case with disk drives using conventional filters. The reduction in heat and the cleaner environment results in a longer life time for a disk drive and a lower probability of losing data, among other things. Further, a company that can manufacture disk drives with higher reliability, longer life time, or a higher density of data is positioned to be more profitable and deliver a more competitive product.
The conventional filter 172 has been used for a long time without significant changes in its design other than varying its size. Therefore, there has been a long felt need for the reduction in generated heat, the higher density of stored data, and the cleaner environment provided by a filter manufactured according to various embodiments of the present invention.
Further, the results provided by a filter manufactured according to various embodiments of the present invention are evident by experiment or simulation. Typically, the industry has provided a cleaner environment inside of a disk drive by making the conventional filter 172 bigger. However, this resulted in taking up valuable space inside of the disk drive and in further obstruction of the air flow 170. Therefore, the industry has had a difficult time finding a way to simultaneously solve all of the problems that can be solved by filters manufactured according to various embodiments of the present invention.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and many modifications and variations are possible in light of the above teaching. The embodiments described herein were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.
