KR19990048604A - Nonlinearity reduction Electrostatic fine actuator for head drive of hard disk drive - Google Patents

Abstract

The present invention relates to an electrostatic microactuator for driving a head of a non-linearity-reduced hard disk drive, wherein the stator is divided into a plurality of groups between left and right frames so that a control voltage can be applied, The force is generated due to the difference between the force generated when the left and right sides are moved and the force generated when the center is moved. Therefore, it is possible to reduce the nonlinearity And at the same time, since the left and right movement of the mover and the movement of the center are opposite to each other according to the support of the multi-point of the head mounting board, a force is generated as much as the difference of the forces of both do.

Description

Nonlinearity reduction Electrostatic fine actuator for head drive of hard disk drive

[0001] The present invention relates to an electrostatic microactuator for driving a head of a hard disk drive, and more particularly to a structure for applying a linearization technique to reduce nonlinearity, The present invention relates to an electrostatic small actuator.

As is well known, in a next generation ultra high density hard disk drive system with a recording density of more than 5 Gb / in ² , as the recording density increases, the track density increases and must increase 4-5 times over the current 5000 TPI (Track per inch) , So that the read / write head (R / W head) must be controlled to be placed at a desired position precisely or at high speed. Accordingly, a dual stage system in which a driver is additionally employed in addition to a voice coil motor (VCM) for driving a read / write head in order to improve response and precision roll has been proposed.

For example, a slider-driven linear microactuator to which a linearization technique is applied is known. Such a microactuator is attached to the back of the slider 100 that is set as floating as shown in Fig. To this end, the base plate 210 of the micro-actuator 200 is electrically insulated and bonded to the rear of the slider 100. The base plate 210 has a plurality of comb-like bodies, n fingers are formed for each comb-shaped body, and a plurality of stator 230 are fixedly installed so as to face each other at a predetermined distance from each other. Also, the mover 250 lifted at a predetermined interval in the base plate 210 has a plurality of comb-like bodies, n fingers are formed for each comb-like body, and these fingers are arranged between the fingers of the stator 230 So that it is possible to reciprocate up and down in a linear manner.

The head mounting board 220 is mounted on the base plate 210 at the center of the mover 250 and a read / write head 222 having a head tip is installed on either side. A spring 260 having a predetermined elastic modulus is attached to both ends of the mover 250 and a pair of anchors 270 are attached to the stator 230 and the mover 250, . The spring 260 and the anchor 270 are also fixedly mounted on the base plate 210. Reference numeral 212 on the base plate 210 denotes a signal wiring for transmitting a read / write signal, and reference numeral 214 denotes a signal pad for connecting the signal wiring 212 to the outside.

However, in the conventional microactuator thus configured, since the driving target is not a read / write head but a slider, more force is required than the operation of the head, and the size is also increased. In addition, The thickness of the microactuator structure must be at least 20 times larger than the present thickness, which is difficult to manufacture with current technology. That is, considering only the weight of the slider to be driven, a driving force of 6-8 mN is required to generate 300-400 G required for a notebook hard disk drive in the case of a pico class, Is larger than the size of the slider itself, it is difficult to fabricate the MEMS technology. In addition to the weight of the slider and the airbearing effect generated by the hard disk drive in actual operation, the required driving force is increased . In order to move the slider with the read / write head to the electrostatic actuator, the read / write head may be influenced by the horizontal directional force of the air lift force . Therefore, considering that the air lifting force in the vertical direction is several tens of mN, the driving force to be generated by the electrostatic actuator may exceed 10 mN. In this case, the electrostatic driving method may be unsuitable and it is difficult to manufacture with the micromachining technique.

In addition, the slide-type microactuator improves the linear structure in which the surfaces of the movable electrode and the fixed electrode are parallel to each other, so that the electrode shape of either the fixed electrode or the movable electrode has a slope in a trapezoidal shape, And the slope is slightly different from the design value, there is a problem that the linearity can not be guaranteed.

Accordingly, the present applicant has proposed an electrostatic microactuator having a structure capable of applying a linearization technique, as shown in FIG. 2, in order to reduce nonlinearity. 2, a side wall 310 is formed on the outer side of the stator 300, and a plurality of comb-like bodies are formed on the side wall 310 so that the comb- The fingers 330 of the lower body 320 protrude downward and the fingers 350 of the lower comb body 340 protrude upward to face each other and the mover 400 also has a comb- The fingers 430 of the upper comb body 420 protrude upward and the fingers 450 of the lower comb body 440 protrude downward to face each other and the fingers 450 of the comb- The spring 600 is attached to both ends of the center axis 410 of the mover 400 and is supported by the anchor 700, The mover 400 fixed to the center shaft 410 as the stator 300 is separately designed so that a control voltage can be applied, Because of the structure that can be applied to the linearization scheme that is moved up was possible linear control.

However, in such a conventional electrostatic microactuator, there is a problem that when the mover moves, eccentric motion occurs around the signal pad.

SUMMARY OF THE INVENTION The present invention has been made in order to solve these problems, and it is an object of the present invention to provide a structure capable of applying a linearization technique in order to reduce nonlinearity, Type microactuator.

As a means for achieving this object, in the electrostatic microactuator for driving a head of a non-linearity-reduced hard disk drive of the present invention, the stator is separately designed into a plurality of groups between left and right frames so that a control voltage can be applied, And the force is generated by the difference between the force generated when the left and right sides are moved and the force generated when the center is moved by reversing the directionality of the right and left sides and the center by the two-point support.

According to the present invention, the stator is divided into a plurality of groups in order to reduce the non-linearity. Since the left and right movements of the mover are pulled up toward the stator and the center movements are pulled down toward the stator, Therefore, eccentricity is prevented.

1 is a schematic configuration diagram showing a micro-actuator for driving a head of a conventional hard disk drive,

FIG. 2 is a configuration diagram of a center axis fixing system showing a head actuating microactuator of a conventional nonlinearity reduction hard disk drive,

3 is a block diagram showing an electrostatic microactuator for driving a head of a non-linearity-reduced hard disk drive according to the present invention.

Description of the Related Art

100; Slider 200; Minute driver

210; A base plate 212; Signal wiring

214; Signal pad 220; Head mounting substrate

222; Read / write head 230; Stator

250; Mover 260; spring

270; Anchor 300; Stator

310; Side walls 320, 340; Upper and lower comb upper body

320, 350; Finger 400; Mover

410; A central axis 420, 440; Upper and lower comb upper body

430,450; Finger 500; Head mounting substrate

600; Spring 700; anchor

800; Stator 802, 804; Left and right frames

810, 820; Fingers 812, 814; The first and second comb-

822,824; A third comb-shaped body group 900; Stator

910, 920; Fingers 902, 904; Upper and lower frames

906,908; Left and right frames 912 and 914; The fourth and fifth comb-shaped bodies

922,924; The sixth interdental group

These and other objects and advantages of the present invention will become more apparent from the following description of the preferred embodiments of the present invention with reference to the accompanying drawings.

Hereinafter, an electrostatic microactuator for driving a head of a nonlinearly reduced hard disk drive according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 3, the electrostatic microactuator of the present invention is characterized in that a stator 800 is mounted on the stator 800, A plurality of groups, for example, three sections are separately designed between the left and right frames 802 and 804 so that a control voltage can be applied, and the mover 900 is designed such that the directions of the left and right sides and the center are opposite to each other have.

That is, the stator 800 includes a plurality of fingers 810 protruding downward at predetermined intervals, first and second comb bodies 812 facing the left and right frames 802 and 804 at predetermined intervals, respectively, And a plurality of fingers 820 protruding upward at a predetermined interval are formed respectively and the third group of comb teeth 822 and 824 arranged at predetermined intervals are formed up and down.

On the other hand, the mover 900 is divided into upper and lower parts around the head mounting board 500, and the downward protruding fingers 810 of the first and second comb groups 812 and 814 on the upper and lower sides of the stator 800 906 of the upper and lower frames 902 and 904 such that a plurality of fingers 910 protrude upward at predetermined intervals between the upper and lower frames 902 and 904 912) 914 and a plurality of upwardly protruding fingers 820 of the upper and lower third comb bodies 822, 824 of the stator 800, a plurality of fingers 920 are projected downward at predetermined intervals A plurality of sixth comb bodies 922 and 924 connecting the left and right frames 906 and 908 of the upper and lower frames 902 and 904 are vertically formed.

Between the upper frame 902 of the mover 900 and the head mounting board 500 are provided upwardly protruding fingers 820 of the uppermost comb elements of the upper and lower third comb groups 822 and 824 of the stator 800, The finger 920 is projected downward to correspond to the finger 920.

The springs 600 are attached to both ends of the upper and lower frames 902 and 904 of the mover 900 and are respectively supported by the anchors 700.

When a voltage is applied to the stator 800 and the mover 900, the microactuator of the present invention having the above-described structure generates attraction force between the two electrodes as follows.

T is the thickness of the electrode, g is the gap between the mover and the electrode of the stator, and V is the applied voltage.

As can be seen from the above equation, the other variables except for the applied voltage are constants, so that the generation force is F = K V ² (K is a constant), the nonlinear characteristic of the square form of the voltage is exhibited, and the applied voltage is referred to as " DC bias voltage V _bias ) &Quot; and " control voltage ( V _control ) &Quot; and expressing the above expression again,

F = K ( _Vbias + _Vcontrol ) ² .

Therefore, the electrostatic microactuator of the present invention is designed so that the stator 800 is vertically separated, F ₁ , F ₂ In this case,

F = K (V _bias + V _control ) ² -K (V _bias -V _control ) ² = 4KV _bias V _control .

Thus, in a quadratic relationship between an existing force and a voltage, a fixed DC bias voltage V _bias ) Control voltage ( V _control ), It becomes possible to control as a linear relationship when controlling the generating force. To do this, two types of control voltages V _control ) And ( -V _control The stator must be designed separately.

3, power is applied from upper, lower, left and right frames 802 and 804 of the stator 800, power is applied from the upper frame 932 of the mover 900, Force that occurs when moving F ₁ And the force generated by the movement of the center F ₂ And a force is generated as a difference between the two.

As described above, according to the low-profile microactuator of the present invention, when the generation force is adjusted only by the control voltage under the fixed DC bias voltage state in the quadratic relationship between the conventional force and the voltage, not only can the control be performed in a linear relationship, The eccentricity at the time of movement by the elastic member is prevented.

As described above, the electrostatic microactuator for driving the head of the non-linearity-reduced hard disk drive of the present invention is designed so that the stator can be applied with a ± control voltage, and a linearization technique can be applied to reduce nonlinearity And at the same time, since the left and right movement of the mover and the movement of the center are opposite to each other in accordance with the multi-point support of the head mounting board, the force is generated as much as the difference of the forces of both, and eccentricity is prevented .

Claims (3)

A stator having a plurality of comb-like bodies, n fingers formed on each of the comb-shaped bodies, and fixedly attached to the base plate at predetermined intervals in an up-down, right-left, A mover provided with n fingers for each comb-shaped body and linearly movable between fingers of the stator, a head mounting board provided with a head and disposed between the stator and the mover, An electrostatic microactuator for driving a head of a hard disk drive, the electrostatic microactuator comprising: a spring attached to the mover with a coefficient; and an anchor for supplying power to the stator and the mover and supporting the spring, The stator is designed to be divided into a plurality of groups between left and right frames so that a control voltage can be applied. The stator is reversed in the direction of left and right by the two-point support, Wherein a force is generated due to a difference between a force generated by the magnetic field generated by the magnetic head and a force generated by the magnetic head. The method according to claim 1, The stator includes a plurality of fingers protruding downward at predetermined intervals, first and second comb bodies arranged inwardly at predetermined intervals from the left and right frames, and a plurality of fingers protruding upward at a predetermined interval, A third group of comb teeth arranged at a predetermined interval is configured as a top and a bottom, The moving member is divided into upper and lower parts with respect to the head mounting substrate. The upper and lower protrusions of the upper and lower frames are arranged such that a plurality of fingers protrude upward at predetermined intervals between the downwardly protruding fingers of the first and second comb- A plurality of fourth and fifth comb body groups outwardly extending along the left and right frames of the stator and a plurality of upwardly protruding fingers of the upper and lower third comb body groups of the stator, A plurality of sixth interdigital assemblies for connecting the left and right frames of the frame are formed in the upper and lower portions of the upper and lower frames so as to correspond to the upwardly protruding fingers of the uppermost comb bodies of the upper and lower third interdigital assemblies of the stator, And a plurality of downward protruding fingers are formed on the head mounting board. The head drive actuator for the drive Electrostatic smile. The method according to claim 1, Wherein power is applied to upper and lower left and right frames of the stator and power is applied to an upper frame of the mover.