The present invention relates to the field of electrical interconnect, and more particularly to an electrical lead suspension having partitioned air slots.
Hard disk drives are used in almost all computer system operations. In fact, most computing systems are not operational without some type of hard disk drive to store the most basic computing information such as the boot operation, the operating system, the applications, and the like. In general, the hard disk drive is a device which may or may not be removable, but without which the computing system will generally not operate.
The basic hard disk drive model was established approximately 50 years ago and resembles a phonograph. That is, the hard drive model includes a storage disk or hard disk that spins at a standard rotational speed. An actuator arm with a suspended slider is utilized to reach out over the disk. The arm carries a head assembly that has a magnetic read/write transducer or head for reading/writing information to or from a location on the disk. The complete head assembly, e.g., the suspension and head, is called a head gimbal assembly (HGA).
In operation, the hard disk is rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are tracks evenly spaced at known intervals across the disk. When a request for a read of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head writes the information to the disk.
Over the years, the disk and the head have undergone great reductions in their size. Much of the refinement has been driven by consumer demand for smaller and more portable hard drives such as those used in personal digital assistants (PDAs), MP3 players, and the like. For example, the original hard disk drive had a disk diameter of 24 inches. Modern hard disk drives are much smaller and include disk diameters of less than 2.5 inches (micro drives are significantly smaller than that). Advances in magnetic recording are also primary reasons for the reduction in size.
However, the decreased track spacing and the overall reduction in HDD component size and weight have resulted in problems with respect to the electrical lead suspension (henceforth referred to as ELS), used in a Data Access Storage Device (DASD), e.g., a hard disk drive (HDD). For example, a typical ELS is formed from a laminate comprised of at least three layers of material. These laminate layers may include a signal-conductor layer from which signal traces are formed, a dielectric layer for insulation supporting the signal-conductor layer, and a conductive base-metal layer supporting the dielectric layer.
Prior Art
An electrical lead suspension (ELS) having partitioned air slots. The ELS includes a laminate. A first plurality of signal traces and a second plurality of traces are in a first formed layer of the laminate. The second plurality of traces may be signal traces or power traces. The laminate has a dielectric layer between the first formed layer and a second formed layer. A plurality of partitioned air slots is in the second formed layer of the laminate. The portion of the ELS having a plurality of partitioned air slots supporting the at least the first plurality of signal traces and the portion of the ELS having a second plurality of partitioned air slots or patterns supporting the second plurality of traces. The supporting of the first plurality of signal traces separate from the second plurality of traces reduces write-to-read cross talk and signal loss. Offsetting the first plurality of air slots from second plurality of air slots further reduces cross talk and signal loss and restores some of the structural rigidity lost due to in line (e.g., aligned) slots.
Prior Art
a is a top view of a portion of an ELS having read and write traces supported individually by aligned a first air slot pattern and a second air slot pattern, respectively, of a dual partitioned air slot pattern, in accordance with one embodiment of the present invention.
b is a top view of a portion of an ELS having read and write traces supported individually by a first offset air slot pattern misaligned with a second offset air slot pattern, respectively, of a dual offset air slot pattern, in accordance with one embodiment of the present invention.
a is a bottom plan view of ELS 127 showing an aligned dual partitioned air slot pattern support as it traverses the hinge area of ELS 127, in accordance with an embodiment of the present invention.
b is a bottom plan view of ELS 127 showing a misaligned dual offset air slot pattern support as it traverses the hinge area of ELS 127, in accordance with an embodiment of the present invention.
Reference will now be made in detail to the alternative embodiment(s)s of the present invention, an electrical lead suspension having partitioned air slots. While the invention will be described in conjunction with the alternative embodiment(s), 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 detailed description of the present invention, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be recognized by one of ordinary skill in the art that the present invention may be practiced without these specific details. 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.
The discussion will begin with an overview of an electrical lead suspension (ELS) in conjunction with its operation within a hard disk drive and components connected therewith. The discussion will then focus on embodiments of a method for an electrical lead suspension having partitioned air slots in particular.
With reference now to
In the embodiment shown, each arm 125 has extending from it at least one cantilevered load beam and electrical lead suspension (ELS) 127. It should be understood that ELS 127 may be, in one embodiment, an integrated lead suspension (ILS) that is formed by a subtractive process. In another embodiment, an additive process, such as a Circuit Integrated Suspension (CIS), may form ELS 127. In yet another embodiment, ELS 127 may be a Flex-On Suspension (FOS) attached to base-metal or it may be a Flex Gimbal Suspension Assembly (FGSA) that is attached to a base-metal layer. The ELS may be any form of lead suspension that can be used in a Data Access Storage Device, such as a HDD. A magnetic read/write transducer or head is mounted on a slider 129 and secured to a flexure that is flexibly mounted to each ELS 127. The read/write heads magnetically read data from and/or magnetically write data to disk 115. The level of integration called the head gimbal assembly is the head and the slider 129, which are mounted on ELS 127. The slider 129 is usually bonded to the end of ELS 127.
ELS 127 has a spring-like quality, which biases or presses the air-bearing surface of the slider 129 against the disk 115 to cause the slider 129 to fly at a precise distance from the disk. ELS 127 has a hinge area that provides for the spring-like quality, and a flexing interconnect (or flexing interconnect) that supports read and write traces through the hinge area. A voice coil 133, free to move within a conventional voice coil motor magnet assembly 134 (top pole not shown), is also mounted to arms 125 opposite the head gimbal assemblies. Movement of the actuator 121 (indicated by arrow 135) by controller 119 causes the head gimbal assemblies to move along radial arcs across tracks on the disk 115 until the heads settle on their set target tracks. The head gimbal assemblies operate in a conventional manner and always move in unison with one another, unless drive 111 uses multiple independent actuators (not shown) wherein the arms can move independently of one another.
Although embodiments of the present invention are described in the context of an ELS in an information storage system, it should be understood that embodiments may apply to any device utilizing an electrical interconnect that might experience signal loss and cross talk between signal traces. For example, embodiments of the present invention may apply to rigid printed circuit boards. More specifically, embodiments of the present invention may be used in printed circuit boards that are used for high speed signal processing. Embodiments of the present invention are also suitable for use in flexing circuits, e.g., flexing circuits for digital cameras and digital camcorders. The signal traces may also be replaced with power traces according to one embodiment.
In one embodiment, the air slot patterns 430a and 430b are both sets of repeating narrow open air slots, formed in the stainless steel ground plane 802 in a location which would be under one of each signal conductor pair (e.g., read 130/write 120 traces of
a is a top view of a portion 400 of an ELS tail portion, e.g., ELS tail portion 309 of
In one embodiment, the air slot patterns are both sets of repeating narrow open air slots, e.g., 430a and 430b respectively, formed in the stainless steel ground plane 802 under each signal conductor pair (e.g., read 130/write 120 traces) on a tail portion of the ELS or other portion of the ELS such as the suspension interconnect portion. The added air slots, e.g., 430a and 430b, reduce signal amplitude loss by disrupting/reducing flow of differential return currents. Also, the independent offset and unconnected air slots, e.g., 430a and 430b , in the ground plane 802 for each conductor pair, reduce read to write coupling/cross talk.
For example, the portion 400 of
That is, in one embodiment, the air slots 430a and 430b are 30 to 50 μm wide and go across both conductors in a pair as shown. Instead of using a common slot for both read 130 and write 120 conductor pairs, each pair has a partition portion 440. That is, the air slots 430a of support portion 410a under write traces 120 are separated from the air slots 430b of support portion 410b under read traces 130 by the partition 440. The added partition 440 to the air slots disrupt/reduce the flow of differential return currents in the ground plane 802 resulting in lower signal loss throughout the tail portion of the ELS. Also independent and unconnected air slots 430a and 430b in the ground plane 802 for each conductor pair reduce read to write coupling and work like a shield against cross talk between adjacent signal conductor pairs and surrounding interference signals inside the hard-disk-drive 111 enclosure.
According to one embodiment, the layered laminate from which the ELS 127 is formed comprises at least a signal-conductor layer, e.g. copper alloy, a dielectric layer, e.g. polyimide, and a base-metal layer, e.g. stainless steel. The dielectric layer is sandwiched between the signal-conductor layer and the base-metal layer to form a laminate. The plurality of read traces 130 and the plurality of write traces 120 can be formed of the layer of signal-conductor layer. Although copper alloy is specified herein, it should be understood that any material having high electrical conductivity, from which write traces 120 and read traces 130 can be formed, may be substituted for the copper alloy. The dielectric layer can be any dielectric that would be appropriate for insulating the read and write traces from the supporting base-metal layer.
Still referring to
According to one embodiment of the present invention, the mechanical stiffness of tail portion 309 of
In one embodiment, supports 410a and 410b are formed from a single piece of a base-metal layer to form the desired partitioned air slot pattern. In another embodiment, supports 410a and 410b are formed from two pieces of a base-metal layer that are fit together to form the desired dual partitioned air slot pattern. In yet another embodiment, supports 410a and 410b are formed from a plurality of pieces of a base-metal layer that are fit together to form the desired partitioned air slot pattern. In one embodiment, the air slot patterns are formed in the base-metal layer via stamping, etching, molding, casting, cutting or the like.
b is a top view of a portion 450 of an ELS tail portion, e.g., ELS tail Portion 309 of
In one embodiment, the air slot patterns are both sets of repeating narrow open air slots, e.g., 460a and 460b respectively, formed in the stainless steel ground plane 802 under each signal conductor pair (e.g., read 130/write 120 traces) on a portion of the ELS 127 such as on the tail portion, a suspension interconnect, or the like. The added air slots, e.g., 460a and 460b, reduce signal amplitude loss by disrupting/reducing flow of differential return currents. Also, the independent offset and unconnected air slots, e.g., 460a and 460b, in the ground plane 802 for each conductor pair, reduce read to write coupling/cross talk.
For example, the portion 450 of
That is, in one embodiment, the air slots 460a and 460b are 30 to 50 μm wide and go across both conductors in a pair as shown. Instead of using a common slot for both read 130 and write 120 conductor pairs, each pair has a separate series of slots offset from the other one. That is, the air slots of 460a under write traces 120 are offset from the air slots 460b under read traces 130. The added offset air slots disrupt/reduce the flow of differential return currents in the ground plane 802 resulting in lower signal loss. Also independent, offset and unconnected air slots 460a and 460b in the ground plane 802 for each conductor pair, reduce read to write coupling and work like a shield against cross talk between adjacent signal conductor pairs and surrounding interference signals inside the hard disk-drive 111 enclosure.
According to one embodiment, the layered laminate from which the structure 450 is formed comprises at least a signal-conductor layer, e.g. copper alloy, a dielectric layer, e.g. polyimide, and a base-metal layer, e.g. stainless steel. The dielectric layer is sandwiched between the signal-conductor layer and the base-metal layer to form a laminate. The plurality of read traces 130 and the plurality of write traces 120 can be formed of the layer of signal-conductor layer. Although copper alloy is specified herein, it should be understood that any material having high electrical conductivity, from which write traces 120 and read traces 130 can be formed, may be substituted for the copper alloy. The dielectric layer can be any dielectric that would be appropriate for insulating the read and write traces from the supporting base-metal layer.
Still referring to
According to one embodiment of the present invention, the mechanical stiffness of the ELS 127, and portion 450 thereof of
In one embodiment, supports 455a and 455b are formed from two pieces of a base-metal layer that are fit together to form the desired dual offset air slot pattern. In another embodiment, supports 455a and 455b are formed from a single piece of a base-metal layer to form the desired dual offset air slot pattern. In yet another embodiment, supports 455a and 455b are formed from a plurality of pieces of a base-metal layer that are fit together to form the desired dual offset air slot pattern. In one embodiment, the offset patterns are formed in the base-metal layer via stamping, etching, molding, casting, cutting or the like.
In one embodiment, the air slot pattern 410a is a set of repeating narrow open air slots formed in the stainless steel ground plane 802 under one signal conductor pair (e.g., read 130 or write 120 traces) on a tail portion of the ELS or other portion of the ELS such as the suspension interconnect portion.
The single air slot pattern 410a keeps the plurality of write traces 120 separate from the plurality of read traces 130 reduces write-to-read cross talk and signal loss.
In one embodiment, the air slots 410a are 30 to 50 μm wide and go under one of the conductor pairs. Instead of using a common slot for both read 130 and write 120 conductor pairs, only one pair has an air slot. That is, the air slots (eg., 410a or 410b of
With reference now to
Flexing interconnect 300 of ELS 127 can be formed of a laminate that is, according to one embodiment, of at least three layers of materials. A signal-conductor layer may be a highly conductive metal, e.g., copper, from which the read and write traces 130 and 120, respectively are formed. A middle layer can be an insulating dielectric layer, e.g., polyimide, separating the top layer from which write and read traces 120 and 130 respectively, are formed of a base-metal layer 802, such as stainless steel, in which offset air slots are formed.
a is a bottom plan view 600 of an ELS 127 showing dual air slot pattern supports 410a and 410b having dual air slots e.g., 430a and 430b of
b is a bottom plan view 650 of an ELS 127 showing dual offset air slot pattern supports 455a and 455b having offset and independent dual airslots e.g., 460a and 460b of
With reference now to step 702 of
Referring now to step 704 of
With reference now to step 706 of
Thus, the present invention provides, in various embodiments, an electrical lead suspension having partitioned air slots. Although embodiments of the present invention are described in the context of an ELS in an information storage system, it should be understood that embodiments may apply to any device utilizing an electrical interconnect that might experience signal loss and cross talk between signal traces. For example, embodiments of the present invention may apply to rigid printed circuit boards. More specifically, embodiments of the present invention may be used in printed circuit boards that are used for high speed signal processing. Embodiments of the present invention are also suitable for use in flexing circuits, e.g., flexing circuits for digital cameras and digital camcorders. According to one embodiment, the signal traces may be replaced with power traces.
The foregoing descriptions of specific embodiments 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 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.
Number | Name | Date | Kind |
---|---|---|---|
3222022 | Akin, Jr. | Dec 1965 | A |
5712749 | Gustafson | Jan 1998 | A |
5781379 | Erpelding et al. | Jul 1998 | A |
5796552 | Akin et al. | Aug 1998 | A |
5812344 | Balakrishnan | Sep 1998 | A |
5995329 | Shiraishi et al. | Nov 1999 | A |
6038102 | Balakrishnan et al. | Mar 2000 | A |
6046886 | Himes et al. | Apr 2000 | A |
6249404 | Doundakov et al. | Jun 2001 | B1 |
6268981 | Coon et al. | Jul 2001 | B1 |
6295183 | Nuno et al. | Sep 2001 | B1 |
6351348 | Erpelding et al. | Feb 2002 | B1 |
6404594 | Maruyama et al. | Jun 2002 | B1 |
6636382 | Shiraishi | Oct 2003 | B2 |
6673256 | Takasugi | Jan 2004 | B2 |
6714385 | Even et al. | Mar 2004 | B1 |
6762913 | Even et al. | Jul 2004 | B1 |
6944936 | Krinke | Sep 2005 | B2 |
7206154 | Lee et al. | Apr 2007 | B2 |
7372669 | Deguchi et al. | May 2008 | B2 |
7408744 | Cuevas | Aug 2008 | B1 |
20020089791 | Morley et al. | Jul 2002 | A1 |
20020105760 | Someya | Aug 2002 | A1 |
20020181156 | Shiraishi et al. | Dec 2002 | A1 |
20030193753 | Arai et al. | Oct 2003 | A1 |
20040264056 | Jang et al. | Dec 2004 | A1 |
20050180053 | Dovek et al. | Aug 2005 | A1 |
20050219758 | Roth | Oct 2005 | A1 |
20060152854 | Arya et al. | Jul 2006 | A1 |
20060152855 | Arya et al. | Jul 2006 | A1 |
20060158783 | Arya et al. | Jul 2006 | A1 |
20060245112 | Shum | Nov 2006 | A1 |
Number | Date | Country |
---|---|---|
2001256627 | Sep 2001 | JP |
2002170215 | Jun 2002 | JP |
200303810 | Jan 2003 | JP |
2003030810 | Jan 2003 | JP |
WO9814937 | Apr 1998 | WO |
Number | Date | Country | |
---|---|---|---|
20060158785 A1 | Jul 2006 | US |