CN102270488B - Hard disk slider internally installed with actuator synthesising two-stage location with thermal high-fly control - Google Patents

Abstract

The invention discloses a hard disk slider internally installed with an actuator synthesising a two-stage location with a thermal high-fly control, comprising two actuators symmetrically disposed on a protective layer under a read head by taking the head as a centre, wherein the actuator mainly comprises a heater and a radiator. The heater is started to generate two drive forces with reverse directions on the head in a take-off direction to perform a two-stage location and generate two drive forces with the same direction in a direction perpendicular to a disk to perform a high-flying control. Additionally, because the radiator conducts the heat generated by the heater to a magnetic recording media via an air bearing, the response frequency of a micro-driver based on a thermal expansion mechanism in the invention can be greatly increased, and the difficulty of performing a write operation on a high-coercivity media under a micro field intensity can be reduced.

Description

Hard disk slider with built-in two-stage positioning and thermal fly height control composite actuator

technical field

The invention belongs to the technical field of computer storage devices, and in particular relates to a hard disk slider with a built-in secondary positioning and thermal flyover control composite actuator. the

Background technique

With the rapid expansion of the digital universe, the amount of information to be stored will increase from 1.6×10 ²⁰ bits in 2006 to 5.3×10 ²² bits in 2020. In order to meet this astonishing storage growth demand, as the most important non-volatile storage device in current large-scale storage applications, it is very important that hard disk drives continue to increase rapidly in storage capacity. The recording density of current hard disk products has reached about 500Gb/in ² , and is expected to maintain an annual growth rate of 30% to 50%. However, the storage industry believes that if the traditional recording method is used, the recording density limit is 1Tb/in ² . The root cause of this limit is the superparamagnetic effect caused by the continuous reduction of recording medium particles. In order to solve this problem, the coercive force of the magnetic storage medium must be increased, and how to write to the high coercive force medium under the condition of micro-field strength has become a current research hotspot.

Due to the improvement of storage density, the track width and bit width of the disk have reached the sub-micron level. The first-level positioning of the magnetic head generally adopts the voice coil motor closed-loop servo method, which is very difficult to control the positioning of sub-micron magnetic tracks. Therefore, on the basis of primary positioning, various forms of secondary positioning actuators have emerged one after another. According to the driving mechanism, the micro-actuators currently available for secondary positioning can be divided into three types: piezoelectric ceramics, electrostatic and thermal expansion. Among them, piezoelectric ceramics require high driving voltage, the assembly of electrostatic driving is complicated, and the response frequency of thermal expansion is low. At present, academia and industry are mainly researching and using piezoelectric ceramics for secondary positioning drive. the

In addition, with the rapid development of material preparation science and microelectronics technology, the track positioning mechanism of computer hard disk is constantly developing towards miniaturization. The magnetic head has developed from the initial 4mm×3mm×0.8mm, weighing 55mg to the current 0.85mm×0.70mm×0.23mm, weighing 0.6mg—a reduction of about 90 times. With such a small head size, the fabrication and installation of the secondary positioning actuator is difficult. the

Along with the improvement of magnetic recording density, the flying height of the magnetic head is getting lower and lower-the current flying height of the magnetic head has been reduced to less than 10nm. In order to achieve such a low flying height, the thermal flying height control slider proposed by Daniel Meyer (D.W.Meyer) in 1999 is generally used in the slider, and the patent application number is US5991113. The design uses a microheater, a small heater with high input power and precise control. The head flying height is further reduced by energizing thermal deformation in the micro heater. the

Contents of the invention

The object of the present invention is to propose a hard disk slider with a built-in secondary positioning and thermal fly height control synthetic actuator, which can realize accurate secondary positioning and thermal fly height control at the same time, and reduce the impact on height under low magnetic field strength. How hard it is for a coercive medium to perform a write operation. the

The hard disk slider with built-in secondary positioning and thermal fly height control synthetic actuator includes a slider substrate, an air bearing surface is provided on the surface of the slider substrate close to the disk platter, and a slider pad is provided on the side of the slider substrate The slider gasket is provided with a top protection layer, an upper protection layer of the reading head and a lower protection layer of the reading head in sequence, a reading head is arranged between the upper protection layer and the lower protection layer of the reading head, and a write coil is wound on the top protection layer , which is characterized in that two actuators are arranged symmetrically with the read head under the lower protective layer, and the actuators include a heater, three heat sinks and an insulating layer, wherein the first and second heat sinks are on the disk The heater is clamped in the direction of the sheet track, the first and second heat sinks are connected together to the third heat sink, the surface of the third heat sink is in contact with the air bearing, and the outside of the first and second heat sink is covered with an insulating layer; the heater is connected to the first heat sink Three heat sinks hold the pitch.

Technical effect of the present invention is reflected in:

When current is applied to the two micro-heaters placed on both sides of the magnetic head in the off-track direction, corresponding heat will be generated in the two micro-heaters, and then thermal expansion will occur. Since two micro-heaters are placed on both sides of the magnetic head, two driving forces in opposite directions (secondary positioning) are generated on the magnetic head in the off-track direction, and two driving forces in the same direction are generated on the magnetic head in the direction perpendicular to the disk platter. (fly height control). By adjusting the current of the two micro-heaters, different driving forces are generated, and finally the required displacement in the off-track direction and the displacement in the direction perpendicular to the disk platter is achieved, so as to simultaneously realize secondary positioning and fly-height control. At the same time, cooling fins are wrapped around the two micro-heaters, and one surface of these cooling fins directly contacts the air bearing. Because the air pressure at the air bearing is very high, and because the flying height of the slider here is relatively low, the heat can be relatively smoothly conducted to the disk medium through the air bearing. In order to make the storage density exceed 1Tb/in ² , it is necessary to use a magnetic disk medium with a higher coercive force. The above heat conducted to the disk medium can be used to preheat the medium. Although it is not enough to make the medium break through the Curie point, it can assist related technologies (such as heat-assisted magnetic recording technology, microwave-assisted magnetic recording medium) to reduce instantaneously to a certain extent. The coercive force of the medium, in order to reduce the difficulty of writing to the high coercive force medium under the micro field strength.

Further, the present invention adopts two micro-heaters, and the micro-heaters can adopt the design of the thermal fly high controller that has been widely used now. Each microheater is surrounded by a heat sink. Each heat sink consists of three fins, two of which sandwich the micro-heater, and a third fin connected to the two and in contact with the air bearing. Two heat sinks first conduct heat from the micro-heater to a third heat sink, which conducts heat to the disk media through air bearings. For heat management, five connected insulating layers are surrounded by two heat sinks, which makes it easier to gather and dissipate heat, and at the same time avoid affecting the read and write accuracy of the magnetic head. Due to the high pressure of the air bearing, heat is transferred smoothly from the head to the platter. The use of the radiator can greatly improve the response frequency of the micro-driver based on the thermal expansion mechanism adopted in the present invention. the

This structure enables the magnetic head to simultaneously perform fly-height control and secondary positioning during data reading and writing, and can relatively reduce the difficulty of writing operations on high-coercivity media under micro-field strength. And because it only adds two miniature heaters and radiators on the basis of the original slider structure, it is easy to manufacture and install. the

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the slider;

Figure 2 is a partial sectional view of the thermal fly height control slider;

Fig. 3 is the partial structure schematic diagram of synthetic actuator slider;

Figure 4 is a partial bottom view of the synthetic actuator slider;

Fig. 5 is a schematic diagram of the structure of the micro-heater in the synthetic actuator. the

Detailed ways

The structure of the synthetic actuator slide block in the present invention will be further described in detail with reference to the accompanying drawings and examples. the

Fig. 1 is an overall structural diagram of a conventional slider, Fig. 2 is a partial cross-sectional view of a conventional thermal fly height controller slider, and Fig. 3 is a schematic diagram of a partial structure of a slider including a synthetic actuator in an embodiment of the present invention. Among them, the larger cube in Figure 1 is the slider substrate, and its lower surface is the air bearing surface, while the smaller cube on the side is the slider gasket, and the magnetic head and the actuator are embedded inside the gasket. In Figure 2, the upper protective layer and the lower protective layer sandwich the read head, and the write head is a helically wound coil. The small circle in the figure is the cross section of the helix, and the thermal fly high controller is under the lower protective layer of the read head. . In Figure 2, perpendicular to the graph, inward (or outward) is the direction away from the current track (referred to as the off-track direction), upward (or downward) is the direction tangent to the current track, and left (or right) is the direction perpendicular to the disk platter. the

Comparing Fig. 2 with Fig. 3 and combining Fig. 4 and Fig. 5, it can be seen that the main components and actuators of the present invention are installed under the lower protective layer of the read head, and are symmetrical with respect to the read head in the off-track direction. the

Fig. 3 is the specific structure of synthetic actuator in the embodiment of the present invention, among the figure radiator is made up of three cooling fins, two parallel cooling fins on track direction sandwich micro heater in the middle, the micro heater The size is smaller than the heat sink. In addition, the cavity between the two heat sinks is air, which is used to isolate the micro heater and the third heat sink. Insulation surrounds the heat sink and micro heater. It can be seen from Figure 3 that the micro-heater is not in contact with the heat sink on the far right of the radiator. The advantage of this design is that after the micro-heater is energized, the heat can be gathered to a certain extent, so that the heat sink and the insulating layer And the area around the insulating layer produces sufficient deformations of different degrees, and then generates enough driving force to drive the magnetic head to perform secondary positioning and fly height control. Due to the insulation layer, the heat gathers in the micro-heater and the radiator. The fins in the radiator that are in contact with the air bearing conduct the heat to the air bearing. Because the pressure of the air bearing is high and the thickness is about ten Therefore, the heat can be further conducted smoothly to the disk medium, and the response frequency of the micro-driver based on the thermal expansion mechanism adopted in the present invention is improved. In addition, this heat preheats the media, making writing to high-coercivity media less difficult at low field strengths. the

Figure 4 is a partial schematic view of the air bearing surface of the composite actuator slider. The two larger rectangles in the gasket in the figure are the faces of the fins in the radiator that are in contact with the air bearing face. The strips and circles in the middle of the extreme top protection layer are the writing coils, wherein the circle drawn with a dotted line is the starting interface of the writing coil, and the strip drawn with a dotted line is the side of the writing coil. A read head is sandwiched between the upper protection layer and the lower protection layer. the

Fig. 5 is a schematic diagram of the structure of the micro-heater in the synthetic actuator. The two micro-heaters in the figure are symmetrical about the symmetry line of the read head. The micro-heater can adopt the structure design of the existing general fly high controller. In addition, two radiators are used to surround two micro-heaters, and the radiator is composed of three radiators. The radiator parallel to the micro-heater in the figure is the second radiator of the radiator (since the first radiator is in the The direction shown in the figure coincides with the second heat sink, so it is not marked), and the heat sink parallel to the air bearing surface is the third heat sink of the radiator. When a corresponding current is added to the first micro-heater, the micro-heater generates thermal deformation, thereby generating a driving force for the read head toward the disk in the direction perpendicular to the disk platter, and generating a driving force toward the second disk in the off-track direction. The force of a micro heater. In the same way, when the corresponding current is added to the second micro-heater, the read head will generate a driving force toward the disk in the direction perpendicular to the disk platter, and a driving force will be generated toward the first micro-heater in the off-track direction. force. It can be seen that, in the off-track direction, the directions of the two driving forces are opposite; in the direction perpendicular to the disk platter, the directions of the two driving forces are the same. By adding corresponding current to the two micro-heaters, the corresponding displacement in the off-track direction and the displacement in the direction perpendicular to the disk platter can be realized, thereby simultaneously realizing secondary positioning and fly-height control. At the same time, since the radiator is used to transfer the heat from the heater to the medium through the air bearing, the response frequency of the synthetic actuator can be improved and the difficulty of writing to high coercivity medium at low magnetic field strength can be reduced . the

The above description is only a preferred embodiment of the present invention, but the present invention should not be limited to the content disclosed in this embodiment and the accompanying drawings. Therefore, all equivalents or modifications that do not deviate from the spirit disclosed in the present invention fall within the protection scope of the present invention. the

Claims (1)

1. The hard disk slider with a built-in two-level positioning and thermal fly height control synthetic actuator includes a slider substrate, an air bearing surface is provided on the surface of the slider substrate close to the disk platter, and a slider A block gasket, the slider gasket is provided with a top protection layer, an upper protection layer of the reading head and a lower protection layer of the reading head in sequence, a reading head is arranged between the upper protection layer and the lower protection layer of the reading head, and the top protection layer is wound with The writing coil is characterized in that two actuators are arranged symmetrically with the read head under the lower protective layer, and the actuators include a heater, three heat sinks and an insulating layer, wherein the first and second heat sinks The heater is clamped in the direction of the disk track, the first and second heat sinks are connected to the third heat sink, the surface of the third heat sink is in contact with the air bearing, and the first and second heat sinks are covered with an insulating layer; the heater There is a distance from the third heat sink.

Images