KR100351671B1 - Stacked optical swing arm for measuring 6-degrees-of-freedom motions of hard disk drive slider - Google Patents

Abstract

It is an object of the present invention to provide a two-stage swing arm optical system for accurately measuring the six degree of freedom dynamic characteristics of a hard disk drive slider.

According to the present invention, in the swing arm optical system for measuring the six degree of freedom motion of the slider 20 of the hard disk drive by using the laser beam scanned from the laser beam scanning device 120, the upper surface of the slider 20 A triangular pyramid shaped triangular reflector 110 fixed to the at least one reflector, and at least one reflector 151 and 152 forming an optical path of the laser beam such that the laser beam is incident on an upper vertex of the triangular reflector 110, and the three surfaces Three position detectors 131, 132, 133 provided in the advancing direction of the three laser beams reflected from the reflector 110, and laser beams detected from the three position detectors 131, 132, 133. The control unit 160 for analyzing the center of gravity of the intensity distribution and the six degrees of freedom of the triangular reflector 110, and the optical path of the laser beam formed on the upper end of the slider 20 is fixed to the lower end 6 DOF of the slider including a two-stage swing arm 140 is formed to be joined to the upper corners of the three sides of the reflector 110 also is provided with a swing arm, an optical system for measuring the motion.

Description

Stacked optical swing arm for measuring 6-degrees-of-freedom motions of hard disk drive slider}

The present invention relates to a swingarm optical system for measuring the movement of the slider that occurs during the operation of a hard disk drive (hereinafter referred to as 'HDD'), which is one of disk-like information storage media, in particular, The present invention relates to a two-stage swingarm optical system having a simple structure that can more accurately measure the motion of a slider using a three-side reflector.

1 is a schematic diagram for explaining the movement of a slider moving on the magnetic disk surface of the HDD.

As shown in FIG. 1, the slider 20 is positioned above the magnetic disk 11 of the HDD 10, and the slider 20 is fixed to the tip of the swing arm 15. An actuator for driving the slider 20 is installed as a voice coil motor (VCM) 12 at the rear end of the swing arm 15, and the swing arm 15 is an E-block 16 having a high rigidity structure. ), A suspension (18) which is an elastic body, and a flexure (19). The E-block 16 is connected in the direction of the magnetic disk 11 at the top of the pivot 14, the suspension 18 is connected to the tip of the E-block 16, the flexure at the tip of the suspension 18 19 is connected, and the slider 20 is fixed to the bottom of this flexure 19. On the other hand, when the magnetic disk 11 rotates in the HDD 10 having such a structure, an air bearing effect occurs between the magnetic disk 11 and the slider 20, and the slider 20 is caused by the air bearing effect. It rises to the upper surface of (11). At this time, the slider 20 is maintained at a constant position by the actuator, and in the normal state in which the rotational speed of the magnetic disk 11 is constant, the distance FH (flying height) between the magnetic disk 11 and the slider 20 is increased. Stays constant.

Meanwhile, in the process of recording and reading data from the HDD 10, the slider 20 maintains a track following state that follows a certain track or performs a track search movement of moving from one track to another track. In the track following state, the distance between the magnetic disk 11 and the slider 20 is kept constant, and the posture of the slider 20 is also kept constant. However, the track search movement is made by swinging the swing arm 15 about the pivot 14 axis, so that the slider 20 moves along an arc-shaped rule according to the swing of the swing arm 15. Accordingly, during the track search movement, the actuator accelerates and decelerates, and thus the suspension 18 and the flexure 19 are deformed and the attitude of the slider 20 is changed.

On the other hand, in order to increase the data storage density of the HDD 10, it is preferable to minimize the gap FH between the slider 20 and the magnetic disk 11. In addition, in order to increase the operating speed of the HDD, the swing arm 15 must be driven quickly so that the slider 20 can fly quickly above the surface of the magnetic disk 11. However, the smaller the distance between the slider 20 and the magnetic disk 11, the higher the probability of collision between the slider 20 and the magnetic disk 11, and the higher the driving speed of the slider 20, the more likely it is to collide. Is higher. In the development of high speed and large capacity HDD, a number of research and development is in progress to overcome this phenomenon, and has undergone many trial and error. However, in order to maintain the gap of the quasi-contact state between the slider and the magnetic disk described above, it is required to quantitatively identify the dynamic characteristics of the slider under the influence of the actuator, the swing arm and the air bearing, and to reflect it in the design.

As described above, various articles for quantitatively identifying the dynamic characteristics of the slider have been introduced.

Figure 2 is a schematic conceptual view of the height measurement system of the conventional HDD slider.

As shown in FIG. 2, the flotation height measuring system of the HDD slider is a device for measuring the distance FH between the magnetic disk 11 and the slider 25, and is formed of a capacitive material on the surface of the magnetic disk 11. A device for printing a pattern and measuring the distance between the slider 25 and the magnetic disk 11 equipped with a rail of capacitive material using a capacitive sensor.

On the other hand, Figure 3 is a schematic diagram showing a system for measuring the height and roll angle and pitch angle of the conventional HDD slider.

As shown in FIG. 3, the system for measuring the lift height, the roll angle and the pitch angle of the HDD slider 20 uses the magnetic disk 11 and the slider using two laser beams output from the laser Doppler vibrometer 30. The space | interval FH between 20, a roll angle, and a pitch angle are measured.

In addition, Figure 4 is a schematic diagram of a system for measuring the height of the flotation of the conventional HDD slider with a photosensor.

The floating height measuring system of the slider shown in FIG. 4 is for measuring the floating height between the magnetic disk and the slider 20 using laser interference. As shown in FIG. 4, the measurement through the back of the disc is possible by using a transparent glass disc instead of the magnetic disc.

However, the above-described HDD slider motion measuring apparatus and system are implemented only for the track following state of the slider, and the motion measurement object of the slider is also limited to the distance (FH), the roll angle and the pitch angle between the slider and the magnetic disk. Therefore, no mention is made of an apparatus and system for measuring the rapid displacement of the slider according to the track search movement of the slider.

The present invention is provided to solve the problems of the prior art as described above, it is possible to accurately measure the dynamic characteristics of the slider according to the track tracking state and track search movement of the HDD slider, and six freedom of the HDD slider having a simple structure It is an object of the present invention to provide a two-stage swingarm optical system for measuring the degree of motion.

1 is a schematic diagram for explaining the movement of the slider moving on the surface of the magnetic disk of the HDD,

2 is a schematic conceptual diagram of a floating height measuring system of a conventional HDD slider;

Figure 3 is a schematic diagram showing a system for the measurement of the rise height and roll angle and pitch angle of the conventional HDD slider,

Figure 4 is a schematic diagram of a system for measuring the height of the flotation of the conventional HDD slider with a photosensor,

5 is a conceptual diagram of a system for measuring six degrees of freedom motion of a measurement object using a three-faced reflector,

6 is a schematic diagram showing six degrees of freedom of the slider of the swing arm shown in FIG.

FIG. 7 is a conceptual diagram illustrating a state in which the six degree of freedom exercise measuring system shown in FIG. 5 is applied to a swing arm to measure the six degree of freedom motion of a slider.

8 is a conceptual diagram of a two-stage swing arm optical system for measuring the six degree of freedom motion of the HDD slider according to an embodiment of the present invention,

9 is a cross-sectional view of the two-stage swing arm optical system shown in FIG.

FIG. 10 is a detailed view illustrating a second reflector installed at a tip portion of the two-stage swing arm illustrated in FIG. 8;

FIG. 11 is another embodiment of a second reflector of the two-stage swingarm optics shown in FIG. 8.

♠ Explanation of symbols on the main parts of the drawing ♠

11 magnetic disk 14 pivot

16: E-block 18: Suspension

19: flexure 20: slider

110: triangular reflector 120: laser beam scanning device

131, 132, 133: position detector 140: two-stage swing arm

151: first reflector 152, 252: second reflector

According to the present invention for achieving the above object, in the swing arm optical system for measuring the six degree of freedom motion of the slider of the hard disk drive using the laser beam scanned from the laser beam scanning device, fixed to the slider A triangular pyramid shaped triangular reflector, at least one reflector forming an optical path of a laser beam such that the laser beam is incident on an upper vertex of the triangular reflector, and a three-pronged laser beam reflected from the triangular reflector Three position detectors respectively installed, a control unit for analyzing the center of gravity of the intensity distribution of the laser beams detected by the three position detectors and the six degrees of freedom of the three-side reflector, and the laser beam along the longitudinal direction while supporting the slider. Slave including a plurality of swing arms are formed of the optical path Swingarm optics are provided to measure Ether's six degree of freedom motion.

Further, the rear ends of the plurality of swing arms of the present invention are connected to the pivot and pivot about the pivot.

In addition, the swing arm of the plurality of stages of the present invention has two stages, a through hole is formed in the front end portion of the upper end of the upper surface of the triangular reflector, the laser beam formed along the longitudinal direction of the swing arm is located at the bottom through the through hole Incident at the vertex.

In addition, the swing arm of the plurality of stages of the present invention is two stages, the upper end is composed of a rigid body without elastic deformation, the lower end of the swing arm is connected to the suspension and the flexure, the bottom of the flexure is fixed to the slider .

In addition, the reflector of the present invention includes a first reflector provided on the upper end of the pivot which is the pivot center point of the two-stage swing arm, and a second reflector provided on the through hole formed on the upper end of the second-stage swing arm, The laser beam scanned from the laser beam scanning apparatus is reflected by the first reflector and the second reflector and is incident on the three-side reflector.

In addition, the first and second reflectors of the present invention have the shape of a right-angled triangular pillar having an inclined surface of 45 °, the inclined surfaces of the first and second reflectors are installed to face each other and scanned from the top of the first reflector The laser beam is reflected on the inclined surface of the first reflector and proceeds to the inclined surface of the second reflector. On the inclined surface of the second reflector, the laser beam reflected from the first reflector passes through the through hole and is formed on the upper surface of the three reflector. Reflect to be incident on the vertex.

In addition, the first and second reflectors of the present invention has a shape of a right angled triangular pillar having an inclined surface of 45 °, the inclined surfaces of the first and second reflectors are installed to face the upper end of the two-stage swing arm The laser beam scanned from the upper part of the first reflector is reflected on the inclined surface of the first reflector and proceeds to the inclined surface of the second reflector, and the laser beam reflected from the first reflector is incident on the inclined surface of the second reflector and the Reflected to pass through the through-hole in the inclined surface of the second reflector to enter the upper vertex of the three-side reflector.

A six-degree of freedom motion measuring apparatus using a three-sided reflector will be described before describing the preferred embodiment of the two-stage swing arm optical system for measuring the six degree of freedom motion of the HDD slider according to the present invention in detail with reference to the accompanying drawings. .

5 is a conceptual diagram of a system for measuring six degrees of freedom motion of a measurement object using a triangular reflector, and FIG. 6 is a schematic diagram showing six degrees of freedom motion of a slider of the swing arm shown in FIG. 5, and FIG. 7. FIG. 5 is a conceptual diagram illustrating a state in which the six degree of freedom motion measuring system shown in FIG. 5 is applied to a swing arm to measure the six degree of freedom motion of a slider.

As shown in FIG. 5, the three-side reflector 110 is fixed to the upper surface of the measurement object 101 to measure the six degree of freedom motion. When the laser beam is incident on the upper vertex of the triangular reflector 110, three reflection beams are generated while forming an angle of 120 °. In this way, the three reflected laser beams are scanned with three position sensitive devices (PSDs) 131, 132, and 133, and the six degrees of freedom motion of the triangular reflector 110 using the equations of predetermined geometric optics (x, y , z, roll, pitch, yaw) The six degrees of freedom motion of the triangular reflector 110 obtained as described above is measured. As shown in FIG. 6, the movement of the slider may be represented by a coordinate system. Rotation amount (roll movement) generated about the longitudinal axis (Xs axis) of the swing arm 40 and the rotation amount (pitch about the Ys axis) of the swing arm 40 during the six degrees of freedom movement. Movement), and the change in height in the vertical direction (Zs axis) is the most important form of movement.

Meanwhile, as shown in FIG. 7, when the slider 20 performs a track search movement, the slider 20 pivots along an arc path around the pivot 14 axis of the swing arm 40. At this time, the laser beam scanning device 120 should follow the circular motion of the slider 20 so that the laser beam is accurately incident on the upper vertex of the three-side reflector (110). When the moving speed of the measuring object 101, that is, the slider 20, is slow, a galvanometer scanner or a precision transfer mechanism can be used for accurate incidence of the laser beam. For the slider, it is quite difficult to accurately inject the laser beam into the upper vertex of the triscopy reflector.

8 is a conceptual diagram of a two-stage swing arm optical system for measuring the six degree of freedom motion of the HDD slider according to an embodiment of the present invention, Figure 9 is a cross-sectional view of the two-stage swing arm optical system shown in Figure 8, FIG. 10 is a detailed view illustrating a second reflector installed at the front end of the two-stage swing arm illustrated in FIG. 8, and FIG. 11 is another embodiment of the second reflector of the two-stage swing arm optical system illustrated in FIG. 8.

As shown in Figure 8, the two-stage swing arm 140 is formed so that the upper and lower ends are parallel to each other, the pivot 14 is connected to the rear end of the upper and lower ends of the two-stage swing arm 140. Therefore, the two-stage swing arm 140 is pivotable about the pivot 14 axis. The lower end of the two-stage swing arm 140 is connected to the E-block 16, the suspension 18 and the flexure 19, the slider 20 is fixed to the bottom of the flexure 19. On the other hand, the actuator for driving the slider 20 is provided as a voice coil motor (VCM) 12 at the rear end of the two-stage swing arm 140. The upper end of the two-stage swing arm 140 is configured as a rigid body with almost no elastic deformation.

On the other hand, the three-side reflector 110 is fixed to the upper surface of the slider 20, the through hole 143 is formed at the tip of the upper end of the two-stage swing arm 140 located above the upper vertex of the three-side reflector 110. . The first reflector 151 and the second reflector 152 are fixed to the upper upper surface of the two-stage swing arm 140.

The first and second reflectors 151 and 152 have a shape of a right triangle pillar having an inclined surface of 45 °, and the first reflector 151 is located on the center upper surface of the pivot 14 axis, and the first reflector 151 45 ° sloped toward the tip of the two-stage swing arm (140). In addition, the second reflector 152 is positioned at the front end of the two-stage swing arm 140, and the 45 ° inclined surface of the second reflector 152 is positioned to face the inclined surface of the first reflector 151 and the second reflector The laser beam reflected by 152 is positioned to be incident on the upper vertex of the triangular reflector 110 located below through the through hole 143 formed at the upper end of the two-stage swing arm 140.

Therefore, as shown in FIG. 9, the laser beam scanned from the laser beam scanning device 120 positioned above the center of the pivot 14 axis is incident on the inclined surface of the first reflector 151, and the first reflector 151 is provided. The laser beam reflected by the light propagates to the inclined surface of the second reflector 152. Then, the laser beam reflected by the second reflector 152 passes through the through hole 143 on the upper end of the two-stage swing arm 140 and enters the upper vertex of the three-side reflector 110.

The laser beam incident on the upper vertex of the three-side reflector 110 is reflected in three directions at 120 ° again. Meanwhile, three position detectors 131, 132, and 133 are installed in the traveling direction of the three-fold reflected laser beam, and the laser beams incident on the respective position detectors 131, 132, and 133 are controlled by voltage signals. It is input to 160. The controller 160 obtains the center of gravity of the laser beam using the voltage signals inputted to the respective position detectors 131, 132, and 133, and obtains the intensity of the incident laser beam. The six degrees of freedom of the triangular reflector 110 are measured by comparing and analyzing the center of gravity and the intensity of the measured laser beam.

In the present invention, even if a track displacement of the slider 20 is performed, as well as a rapid displacement of the two-stage swing arm 140 occurs during the track search, the laser beam scanned from the laser beam scanning device 120 is the two-stage swing arm 140. By the first and second reflectors 151 and 152 and the three reflectors 110, which are displaced together, the laser beam is accurately incident on the upper vertex of the three reflectors 110. Therefore, the reliability of the position detectors 131, 132, and 133, which receive three laser beams reflected from the triangular reflector 110 and generate a voltage signal, also increases, so that six degrees of freedom of the slider 20 can be accurately measured. have.

Here, the inclined surfaces of the first and second reflectors 151 and 152 are mirrors on which metal materials such as aluminum are deposited. Meanwhile, as shown in FIG. 11, the second reflector 152 may also be used as a transparent prism.

The second reflector 252 illustrated in FIG. 11 is fixed with a transparent prism covering the through hole at the top of the two-stage swing arm 140, and the laser beam reflected from the first reflector 151 is the second reflector 252. ) Is incident on the inner side of the inclined surface of the second reflector 252 and is reflected downward. The reflected laser beam is incident to the upper vertex of the triangular reflector 110 through the through hole 143. At this time, inside the inclined surface of the second reflector 252, the refractive index of the prism is larger than the refractive index of the outside air, and the laser beam incident at the incident angle of 45 ° included in the total reflection condition is totally reflected. In addition, the reflected laser beam propagating downward is incident on the lower surface of the second reflector 252 at a vertical angle larger than the total reflection angle, and is transmitted without reflection.

As described in detail above, the two-stage swingarm optical system for measuring the six degree of freedom motion of the slider of the hard disk drive of the present invention can accurately measure the six degree of freedom motion of the slider during the track following state and the track search motion of the slider. There is an advantage.

In addition, since the laser beam scanned from the laser beam scanning apparatus can accurately follow the three-side reflector with respect to the rapid displacement generated by the track search motion of the slider, the reliability of the six degree of freedom motion measurement can be improved.

Although the technical idea of the two-stage swing arm optical system for measuring the six degree of freedom motion of the hard disk drive slider of the present invention has been described with the accompanying drawings, this is illustrative of the best embodiment of the present invention. It is not intended to limit. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

Claims (7)

In the swing arm optical system for measuring the six degree of freedom motion of the slider of the hard disk drive using the laser beam scanned from the laser beam scanning device, A triangular pyramid shaped triangular reflector fixed to the slider; At least one reflector forming an optical path of the laser beam such that the laser beam is incident on an upper vertex of the triangular reflector; Three position detectors each provided in a traveling direction of three laser beams reflected from the three-side reflector; A control unit for analyzing the center of gravity of the intensity distribution of the laser beams detected by the three position detectors and the six degrees of freedom of the triangular reflector; Swing arm optical system for measuring the six degree of freedom movement of the slider, characterized in that it comprises a plurality of swing arms supporting the slider and the optical path of the laser beam is formed along the longitudinal direction. The method of claim 1, The rear end of the plurality of swing arms is connected to the pivot swing arm optical system for measuring a six degree of freedom movement of the slider, characterized in that the pivoting around the pivot. The method according to claim 1 or 2, The multi-stage swing arm has two stages, and a through hole is formed at a tip end of the upper end so that the laser beam formed along the longitudinal direction of the swing arm is incident to the upper vertex of the triangular reflector located at the bottom through the through hole. Swing arm optics for measuring the six degrees of freedom motion of the slider. The method according to claim 1 or 2, The swing arm of the plurality of stages are two stages, the upper end is composed of a rigid body without elastic deformation, the lower end of the swing arm is connected to the suspension and the flexure slider, characterized in that the slider is fixed to the lower end of the flexure Swingarm optics for measuring six degrees of freedom motion. The method of claim 3, wherein The reflector includes a first reflector provided at an upper end of the pivot, which is a pivot center point of the two-stage swing arm, and a second reflector provided at a through hole formed at an upper end of the two-stage swing arm, wherein the laser beam scanning device The swing arm optical system for measuring the six degree of freedom motion of the slider, characterized in that the laser beam is scanned from the first reflector and the second reflector is reflected by the three reflectors. The method of claim 5, The first and second reflectors have a rectangular triangular pillar shape having an inclined surface of 45 °, and the inclined surfaces of the first and second reflectors are disposed to face each other so that the laser beam scanned from the upper portion of the first reflector is the first. Reflected from the inclined surface of the first reflector and proceeds to the inclined surface of the second reflector, and reflected from the inclined surface of the second reflector such that the laser beam reflected from the first reflector passes through the through hole and is incident on the upper vertex of the three-side reflector. Swing arm optical system for measuring the six degree of freedom motion of the slider characterized in that. The method of claim 5, The first and second reflectors have a rectangular triangular pillar shape having an inclined surface of 45 °, and the inclined surfaces of the first and second reflectors are installed to face the upper end of the two-stage swing arm, and thus the upper portion of the first reflector. The laser beam scanned from the first reflector is reflected on the inclined plane of the first reflector and proceeds to the inclined plane of the second reflector, and the laser beam reflected from the first reflector is incident on the inclined plane of the second reflector and the inclined plane of the second reflector The swing arm optical system for measuring the six degree of freedom movement of the slider, characterized in that to pass through the through hole and reflected to be incident to the upper vertex of the triangular reflector.