The present disclosure is directed to a magnetic disc apparatus, a magnetic disc medium, a head and a track following method, and in particular to a technology for causing a head to follow tracks on a discrete medium or a patterned medium with high accuracy.
In recent years, the size reduction and capacity increase of magnetic disc apparatuses have been achieved at a rapid pace, and in accordance with this trend, increases in areal density of magnetic disc media have been promoted. In magnetic disc media having high densities, the space between adjacent data tracks is small, which results in problems including magnetic influences from neighboring tracks and thermal fluctuation.
Discrete media and patterned media have been proposed as media capable of preventing such magnetic influences from neighboring tracks and thermal fluctuation in spite of increases in the densities (see Japanese Laid-open Patent Application Publication No. 2004-227654).
As for a discrete medium, interference from neighboring data tracks is reduced by forming grooves between data tracks of the medium body or forming data tracks in grooves of the medium body, thereby increasing the track density. As for a patterned medium, interference between adjacent bits is reduced by forming tiny holes (nano-pores) on the medium body and depositing magnetic particles in the nano-pores (called “patterned bits”), thereby increasing the recording density.
On the other hand, along with the density increases of magnetic disc media, it is necessary to cause heads for magnetic recording and playback processes to follow data tracks with high accuracy. Various methods to cause a head to follow data tracks of a magnetic disc medium have been proposed, and one of such is that a mechanism capable of positioning a head using light is provided and the head positioning is controlled using an optical pickup (Japanese Laid-open Patent Application Publication No. 2001-056744).
The magnetic disc media described above are manufactured by conducting a nano-imprint technique using a master on which tracks are defined in advance.
The master 1 is pressed on the magnetic disc medium 3, as illustrated in
However, in the above method of transferring the pattern 2 of the master 1 by pressing the master 1 on the magnetic disc medium 3, tracks distorted from a perfect circle can be formed on the manufactured magnetic disc medium 3.
In either the servo/data track separated system magnetic disc medium 3A or the sector servo system magnetic disc medium 3B, if distortion occurs as described above, the servo tracks 5 or the servo sectors 7 on the medium body are displaced from their proper positions. This prevents a head from following the data tracks 6 or the servo/data mixed tracks 8 with high accuracy.
In particular, in the sector servo system magnetic disc medium 3B (
In the case of patterned media, it is necessary to accurately detect positions of patterned bits in the circumferential direction in order to perform write/read operations. However, if distortion occurs as described above, displacement may occur in positions at which patterned bits are formed. In such a case, accurate magnetic recording/playback may not be performed.
On the other hand, displacement of the data tracks 6 and the servo/data mixed tracks 8 due to distortion may be compensated by improving the head performance of following the tracks 6 and 8. Japanese Laid-open Patent Application Publication No. 2001-056744 discloses such a technique, and positions of the individual tracks 6 and 8 are detected using light.
The technique disclosed in Japanese Laid-open Patent Application Publication No. 2001-056744 is a so-called dedicated servo system, in which servo information (positioning information) is recorded intensively in one of multiple discs provided, and head positioning is performed by reading the servo information by an optical head. According to the technique, one or more magnetic disc media on which data are recorded and an optical disc medium on which position information is recorded are separately provided.
Accordingly, the above-mentioned distortion could occur on the magnetic disc media independently of the optical disc medium. Therefore, it is not possible to cause the head to accurately follow data tracks having distortion by performing positioning of the head based on the optical disc medium. Thus, the conventional techniques leave the problem that in the case of having distortion on a magnetic disc medium, it is not possible to cause the head to follow the data tracks with high accuracy.
One aspect of the present disclosure is a magnetic disc apparatus including a magnetic disc medium that includes a first part and a second part having light reflection different from light reflection of the first part; a head having a first device for detecting reflectivity on the magnetic disc medium and a second device for performing magnetic recording/playback on the magnetic disc medium; and a positioning unit configured to determine, based on the reflectivity on the magnetic disc medium detected by the first device, a position for the magnetic recording/playback performed by the second device on the magnetic disc medium.
The object and advantages of the disclosure will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.
Next are described embodiments of the present disclosure with reference to the drawings.
The head 14A, 14B or 14C is provided at the tip of a suspension arm 15A, as shown in
The suspension arm 15A is fixed on an arm 13 connected to the VCM 12. The VCM 12 is a motor that generates a driving force for moving the head 14A, 14B or 14C to a predetermined position on the magnetic disc medium 30A, 30B or 30C.
The VCM 12 is drive-controlled by the control apparatus 28. Therefore, when the control apparatus 28 drives the VCM 12, the arm 13 (suspension arm 15A) pivots, whereby the head 14A, 14B or 14C moves to a predetermined position on the magnetic disc medium 30A, 30B or 30C.
The head 14A is used to perform magnetic recording and playback processes on a servo/data track separated system magnetic disc medium 30A of
The slider 16 is made of, for example, a nonmagnetic material, such as ceramic. The slider 16 includes a first slider 17 and the second sliders 18. The first slider 17 functions as a substrate on which various devices 19, 20 and 24 to be described later are mounted.
The head 14A is a so-called floating head, and floats a minute distance above the surface of the magnetic disc medium 30A to perform the magnetic recording and playback processes. Grooves and projections (not shown) to cause the head 14A to float are formed on the slider 16.
The second sliders 18 are disposed on the first slider 17. Each second slider 18 is a piezoelectric element, on which the write device 19 and the read device 20 are mounted. Accordingly, the write device 19 and the read device 20 can be shifted in a direction indicated by arrow Y in
Multiple second sliders 18 (four in the case of the present embodiment) are provided on the first slider 17. The second sliders 18 are provided in such a manner as to correspond to the pitch of data tracks 36 on the magnetic disc medium 30A.
The write devices 19 are employed to perform a recording process on the magnetic disc medium 30A, and the present embodiment adopts perpendicular-magnetic-recording thin film heads as the write devices 19. The read devices 20 are employed to perform a process of reading signals recorded on the magnetic disc medium 30A, and the present embodiment adopts MR heads (magnetoresistance effect heads) as the read devices 20.
The photodetector 21 is provided in the middle of the four second sliders 18 in such a manner that two of the second sliders 18 are positioned on either side of the photodetector 21. The photodetector 21 includes a light emitting device 26 and a light receiving device 27, as shown in
The light emitting device 26 emits a spot light 44 toward the magnetic disc medium 30A. The spot light 44 is reflected by the servo track 35 of the magnetic disc medium 30A, and the reflected light is then received by the light receiving device 27, as described later. As the light receiving device 27, a device capable of detecting the light intensity of the reflected light is used.
A photodetector wire 24 is led out from the photodetector 21. A driving wire 23 is led out from each second slider 18. A recording/playback wire 22 is led out from the write device 19 and the read device 20 disposed on each second slider 18. The individual wires 22 through 24 are connected to the control apparatus 28. The control apparatus 28 is connected to the VCM 12 by a VCM wire 25, and the VCM 12 is drive-controlled by the control apparatus 28, as described above.
The magnetic disc medium 30A is a discrete system and servo/data track separated system medium. The magnetic disc medium 30A, which is a discrete medium, has a structure in which grooves are formed between individual data tracks on the medium body 34, or data tracks are formed in grooves on the medium body 34, thereby reducing interference between each data track and increasing the track density.
Since the magnetic disc medium 30A is also a servo/data track separated system medium, the servo tracks 35 are isolated from the data tracks 36. Therefore, according to the magnetic disc medium 30A of the present embodiment, position information (servo information) of the head 14A can be obtained in a continuous manner using the servo tracks 35.
Next is described the structure of the magnetic disc medium 30A. The magnetic disc medium 30A has a structure in which the servo tracks 35 and the data tracks 36 are formed on the medium body 34.
In the present embodiment, the medium body 34 (corresponding to the “second part” defined in the appended claims) is made of silicon, which is a low reflecting material. On the other hand, the servo tracks 35 and the data tracks 36 (the “first part”) are formed of an iron or cobalt-system magnetic film.
The magnetic film has high reflectivity compared to silicon. That is, the magnetic disc medium 30A of the present embodiment includes the medium body 34 and the individual tracks 35 and 36 exhibiting different reflectivities when light is incident thereon. Note that as long as the medium body 34 and the individual tracks 35 and 36 have different light reflectivities, their materials are not limited to the above.
Next is described a method of manufacturing the magnetic disc medium 30A which includes two parts having different reflectivities when light is incident thereon.
For manufacturing the magnetic disc medium 30A, the medium body 34 made of silicon, which is a low reflecting material, is first provided. On the disc-shaped medium body 34, first, a resist 40 is formed (
Subsequently, using nano-imprint technology, the master 1 is pressed on the resist 40, thereby forming a pattern 41 on the resist 40 (
Next, etching is performed on the medium body 34, using the resist 40 as a mask, and the grooves 42 are formed on the medium body (
After the process of forming the magnetic film 43 is completed, unnecessary magnetic film 43 is removed by lift-off together with the resist 40. In this manner, the magnetic disc medium 30A having the servo tracks 35 and the data tracks 36 formed in the grooves 42 on the medium body 34 is manufactured.
On the other hand,
For manufacturing the magnetic disc medium 30A having such a structure, the disc-shaped medium body 34 made of silicon, which is a low reflecting material, is first provided. On the entire upper surface of the medium body 34, the magnetic film 43 is formed (
Subsequently, the resist 40 is formed over the entire upper surface of the magnetic film 43 (
Then, using nano-imprint technology, the master 1 is pressed on the resist 40, thereby forming the pattern 41 on the resist 40 (
Next, etching is performed on the magnetic film 43, using the resist 40 as a mask. Accordingly, the servo tracks 35 and the data tracks 36 are formed and the grooves 42 are also formed between adjacent tracks 35 and 36 (
Next is described a track following control process carried out when the magnetic recording/playback process is performed on the above-described magnetic disc medium 30A using the head 14A. The track following control process is a positioning control process (servo control process) in which the position of the head 14A on the magnetic disc medium 30A is detected, and a correction is made if there is displacement from its proper position.
When the head 14A moves in the X direction relative to the magnetic disc medium 30A, the photodetector 21 (the “first device” defined in the appended claims) emits the spot light 44 toward a servo track 35 of the magnetic disc medium 30A. Note that the photodetector 21 is provided anterior to the write and read devices 19 and 20 (the “second device”) in the traveling direction of the head 14A, as shown in
As described above, the surface (recording/playback surface) of the magnetic disc medium 30A includes parts at which the individual tracks 35 and 36 having high reflectivity are provided and parts at which the medium body 34 having reflectivity lower than that of the individual tracks 35 and 36 is exposed. Accordingly, as illustrated in
Therefore, if the spot light 44 is out of the servo track 35, the amount of the light reflected by the magnetic disc medium 30A is reduced. A decrease in the amount of the reflected light correlates with the amount of displacement of the spot light 44 from the servo track 35, in other words, correlates with the amount of displacement from the proper position of the head 14A.
A decrease in the amount of the reflected light is detected by the light receiving device 27 of the photodetector 21. Then, a signal (hereinafter, referred to as “position signal”) corresponding to the amount of displacement detected by the photodetector 21 is sent to the control apparatus 28.
Next is described track following control performed by the control apparatus 28.
When the process illustrated in
Next in Step S14, the control apparatus 28 determines whether the amount of displacement calculated in Step S12 is equal to or more than the length that the piezoelectric elements serving as the second sliders 18 are able to shift the write/read devices 19/20. If the amount of displacement of the head 14A exceeds the amount that can be shifted by the piezoelectric elements, the control apparatus 28 drives the VCM 12 to move the head 14A to its proper position.
If the amount of displacement calculated in Step S12 is less than the amount that can be shifted by the piezoelectric elements, in Step S16, the control apparatus 28 shifts the write/read devices 19/20 to their adequate positions using the second sliders 18 formed of piezoelectric elements. According to the above processes in Steps S14 and S16, the write/read devices 19/20 become aligned to the data tracks 36. As a result, in Step S18, the write/read devices 19/20 are able to favorably perform the magnetic recording/playback process on the data tracks 36.
In the present embodiment, as described above, the head 14A has a structure in which the photodetector 21 dedicated to follow the servo track 35 and the write/read devices 19/20 for performing the magnetic recording/playback process on the data tracks 36 are disposed in accordance with the track pitches. Using such a head 14A, the magnetic recording/playback process is performed on the data tracks 36 while the position of the head 14A is being corrected based on the intensity of the reflected light detected by the photodetector 21.
At this point, even if track distortion is present in the servo tracks 35 and the data tracks 36 on the magnetic disc medium 30A due to the above described reason, the tracks 35 and 36 maintain similar regularity (see
In the case of the discrete system magnetic disc medium 30A on which the individual tracks 35 and 36 are densely formed, the track pitch is narrow. Therefore, when the position signal is magnetically read from the servo track 35, magnetic influence from adjacent tracks may arise, which results in a decrease in the accuracy of the position information. However, this problem is eliminated by optically detecting the servo track 35, allowing positioning with high accuracy.
Since the servo tracks 35 are isolated from the data tracks 36, the photodetector 21 (head 14A) is able to obtain the position information of the head 14A in a continuous manner using the servo tracks 35. As a result, it is possible to follow high-order skew (large distortion), and it is also possible to avoid limitation of discrete sampling of the position information, thereby being able to follow the track distortion with high accuracy.
In addition, regarding the off-track amount of the servo track 35, a pattern (a phase pattern indicated by diagonal lines in the figures) which is recorded in the servo tracks 35 is detected. Herewith, according to the amount of reflection from the phase pattern, the off-track amount can be detected, thereby enabling further accurate positioning.
Next is described a magnetic disc apparatus according to the second embodiment of the present disclosure.
The magnetic disc apparatus according to the present embodiment is characterized by using a magnetic disc medium 30B illustrated in
The magnetic disc medium 30B used in the present embodiment is a discrete system and sector servo system medium. In the magnetic disc medium 30B, parts of servo/data mixed tracks 38 are used as servo sectors 37, as shown in
Therefore, unlike the servo/data track separated system magnetic disc medium 30A of the first embodiment described above, the position information (servo information) cannot be obtained in a continuous manner. Track distortion also occurs in the magnetic disc medium 30B, as in the case of the magnetic disc medium 30A (see
Also in the present embodiment, the medium body 34 is made of silicon, which is a low reflecting member, and the servo/data mixed tracks 38 are formed of a magnetic film having reflectivity different from that of silicon. Thus, the magnetic disc medium 30B also includes the medium body 34 and the servo/data mixed tracks 38 having different reflectivities when light is incident thereon.
The head 14B of the present embodiment generally has the same structure as that of the head 14A of the first embodiment. However, the head 14A does not have a second slider 18 corresponding to a track line (line in the X direction), along which the photodetector 21 follows. On the other hand, as illustrated in
Next is described a track following control process carried out when the magnetic recording/playback process is performed on the above-described magnetic disc medium 30B using the head 14B.
When the head 14B moves in the X direction relative to the magnetic disc medium 30B, the photodetector 21 of the present embodiment emits the spot light 44 toward a servo/data mixed track 38 of the magnetic disc medium 30B.
In the proper condition, the spot light 44 emitted from the photodetector 21 is incident at the center (the center position in the track width direction) of the servo/data mixed track 38. When the head 14B is located at the proper position, the write devices 19 and the read devices 20 oppose the corresponding servo/data tracks 38 in an optimum condition, whereby it is possible to favorably perform the magnetic recording/playback process.
In this embodiment also, the surface of the magnetic disc medium 30B includes parts at which the servo/data mixed tracks 38 having high reflectivity are provided and parts at which the medium body 34 having reflectivity lower than that of the servo/data mixed tracks 38 is exposed. Accordingly, as illustrated in
Therefore, if the spot light 44 is out of the servo/data mixed track 38, the amount of the light reflected by the magnetic disc medium 30B is reduced. A decrease in the amount of the reflected light correlates with the amount of displacement of the spot light 44 from the servo/data mixed track 38. Therefore, using the amount of displacement of the spot light 44, it is possible to obtain the amount of displacement of the head 14B from its proper position. A decrease in the amount of the reflected light is detected by the light receiving device 27 of the photodetector 21. Then, a position signal corresponding to the amount of displacement detected by the photodetector 21 is sent to the control apparatus 28.
In the case of the sector servo system magnetic disc medium 30B, along with the travel of the head 14B, the read devices 20 pass over the servo sectors 37 formed in the servo/data mixed tracks 38. Since the position information (servo information) is recorded in the servo sectors 37, the control apparatus 28 may also be able to detect the position of the head 14B according to the position information (servo information) transmitted from the read devices 20. The above-mentioned second slider 18 indicated by arrow P in
Next is explained track following control performed by the control apparatus 28 according to the present embodiment.
When the process illustrated in
Next in Step S24, the control apparatus 28 calculates the amount of displacement of the head 14B from its proper position (the position illustrated in
Next in Step S26, based on the results of the position detection obtained mainly by the recording/playback wires 22, the control apparatus 28 performs a process of driving the VCM 12 to move the head 14B to its proper position so as to correct the positional displacement. Next in Step S28, based on the results of the position detection obtained mainly by the photodetector 21, the control apparatus 28 shifts the write/read devices 19/20 to their adequate positions using the second sliders 18 formed of piezoelectric elements.
According to the above processes in Steps S26 and S28, the write/read devices 19/20 become aligned to the servo/data mixed tracks 38. As a result, in Step S30, the write/read devices 19/20 are able to favorably perform the magnetic recording/playback process on the servo/data mixed tracks 38.
In the magnetic disc medium 30B of the present embodiment also, track distortion may be present in the servo/data mixed tracks 38. However, even if track distortion is present, the tracks 38 of the sector servo system maintain similar regularity (see
The present embodiment also has the following advantageous effects as in the case of the first embodiment: being able to compensate track pitch displacement with higher accuracy since the write/read devices 19/20 are finely adjustable in the cross track direction (Y direction) by the second sliders 18 formed of piezoelectric elements; and being able to eliminate the possibility of being magnetically influenced by adjacent tracks since the servo sectors 37 are optically detected, thereby enabling positioning with high accuracy.
Next is described a magnetic disc apparatus according to the third embodiment of the present disclosure.
The magnetic disc apparatus according to the present embodiment is characterized by using a magnetic disc medium 30C illustrated in
The magnetic disc medium 30C used in the present embodiment is a patterned medium system and servo/data track separated system medium. The magnetic disc medium 30C, which is a patterned medium, has a structure in which patterned bits 47 are provided by forming tiny holes (nano-pores) on the medium body 34 and depositing magnetic particles in the nano-pores. According to this structure, the individual patterned bits 47 are isolated, thereby reducing interference between adjacent patterned bits 47 and increasing the recording density. The patterned bits 47 are aligned in lines in the track direction so as to form data tracks 46.
The magnetic disc medium 30C is also a servo/data track separated system, and therefore, servo tracks 45 are isolated from data tracks 46. Accordingly, the magnetic disc medium 30C of the present embodiment is able to obtain position information (servo information) of the head 14C in a continuous manner using the servo tracks 45, as in the case of the magnetic disc medium 30A of the first embodiment.
As described above, the magnetic disc medium 30C has a structure in which the servo tracks 45 and the data tracks 46 are formed on the medium body 34. In the present embodiment also, the medium body 34 is made of silicon, which is a low reflecting material.
On the other hand, the servo tracks 45 and the data tracks 46 are formed of an iron or cobalt-system magnetic film having reflectivity higher than that of silicon. That is, the magnetic disc medium 30C of the present embodiment includes the medium body 34 and the individual tracks 45 and 46 having different reflectivities when light is incident thereon.
As illustrated in
Next is described a track following control process carried out when the magnetic recording/playback process is performed on the above-described magnetic disc medium 30C using the head 14C.
When the head 14C moves in the X direction relative to the magnetic disc medium 30C, the photodetector 21 of the present embodiment emits the spot light 44 toward a servo track 45 of the magnetic disc medium 30C, and each photodetector 51 emits the spot light 44 toward a corresponding data track 46. As explained in the first embodiment, in the proper condition, the spot light 44 emitted from the photodetector 21 is incident at the center (the center position in the track width direction) of the servo track 45.
Also, the spot light 44 emitted from each photodetector 51 is incident at the center (the center position in the track width direction) of the corresponding data track 46. When the head 14C is located at its proper position, the write devices 19 and the read devices 20 oppose the pattern bits 47 of the data tracks 46 in an optimum condition. Herewith, the write/read devices 19/20 are able to favorably perform the magnetic recording/playback process with respect to the patterned bits 47.
In this embodiment also, the surface of the magnetic disc medium 30C includes parts at which the tracks 45 and 46 having high reflectivity are provided and parts at which the medium body 34 having reflectivity lower than that of the tracks 45 and 46 is exposed. Accordingly, if the head 14C is displaced from the proper position in relation to the magnetic disc medium 30C and each spot light 44 is out of the center position of a corresponding servo track 45 or data track 46, such spot lights 44 are incident also on the medium body 34 having low reflectivity.
Therefore, if the spot light 44 is out of the corresponding servo track 45 or data track 46, the amount of the light reflected by the magnetic disc medium 30C is reduced. A decrease in the amount of the reflected light correlates with the amount of displacement of the spot light 44 from the track 45 or 46. Therefore, using the amount of displacement of the spot light 44, it is possible to obtain the amount of displacement of the head 14C from its proper position. A decrease in the amount of the reflected light is detected by the light receiving device 27 of each photodetector 21 and 51. Then, a position signal corresponding to the amount of displacement detected by each photodetector 21 and 51 is sent to the control apparatus 28.
Next is explained track following control performed by the control apparatus 28 according to the present embodiment.
When the process illustrated in
The patterned bits 47 in the track direction are provided at regular intervals; however, the intervals may become slightly irregular due to an error and the like. The influence of the error appears as cycle deviation of the bit detection signal SR.
Next in Step S44, the control apparatus 28 calculates the amount of displacement of the head 14C from its proper position based on the position of the head 14C obtained in Step S40.
Next in Step S46, the control apparatus 28 determines whether the amount of displacement calculated in Step S44 is equal to or more than the length that the piezoelectric elements serving as the second sliders 18 are able to shift the write/read devices 19/20. If the amount of displacement of the head 14C exceeds the amount that can be shifted by the piezoelectric elements, the control apparatus 28 drives the VCM 12 to move the head 14C to its proper position.
If the amount of displacement calculated in Step S42 is less than the amount that can be shifted by the piezoelectric elements, in Step S48, the control apparatus 28 shifts the write/read devices 19/20 to their adequate positions using the second sliders 18 formed of piezoelectric elements. According to the above processes in Steps S46 and S48, the write/read devices 19/20 become aligned to the data tracks 46. As a result, in Step S50, the write/read devices 19/20 are able to favorably perform the magnetic recording/playback process on the data tracks 46.
According to the present embodiment, the photodetectors 51 are provided on the head 14C in such a manner as to correspond one-to-one with the individual data tracks 46 for the magnetic recording/playback process. On the slider 16 of the head 14C, the photodetectors 51 are provided anterior to the write devices 19 in the X direction (the relative moving direction of the head 14C). That is, the bit detection signals generated by the photodetectors 51 are detected before the write devices 19 perform magnetic recording on patterned bits 47. In addition, the distance between each photodetector 51 and its corresponding write device 19 (indicated by arrow ΔL in
Accordingly, in Step S50, the control apparatus 28 generates a write signal SW (see
According to the structure, even if irregularity has been introduced to the intervals of the patterned bits 47 due to an error or the like, the magnetic recording process is performed based on the write signal SW generated from the bit detection signal SR on which the error is superimporsed, whereby the write devices 19 are able to perform magnetic recording to the patterned bits 47 in a reliable fashion.
In the present embodiment also, as described above, the head 14C has a structure in which the photodetector 21 dedicated to follow the servo tracks 45 and the write/read devices 19/20 for performing the magnetic recording/playback process on the data tracks 46 are disposed in accordance with the track pitches. The position of the head 14C is corrected based on the intensity of the reflected light detected by the photodetector 21. As a result, even if distortion is present in the individual tracks 45 and 46, the positioning accuracy is compensated and the recording/playback process can be performed with high accuracy.
Since the servo tracks 45 are isolated from the data tracks 46, it is possible to obtain the position information of the head 14C in a continuous manner. As a result, even if high-order skew (large distortion) is present in the magnetic disc medium 30C, the track distortion can be followed with high accuracy.
In addition, regarding the off-track amount of each servo tracks 45, a pattern (a phase pattern indicated by diagonal lines in the figures) which is recorded in the servo tracks 45 is detected. Herewith, according to the amount (large or small) of reflection from the phase pattern, the off-track amount can be detected, thereby enabling further accurate positioning.
The present embodiment also has the following advantageous effects as in the case of the first embodiment: being able to compensate track pitch displacement with higher accuracy since the write/read devices 19/20 are finely adjustable in the cross track direction (Y direction) by the second sliders 18 formed of piezoelectric elements; and being able to eliminate the possibility of being magnetically influenced by adjacent tracks since the data tracks 46 are optically detected, thereby enabling positioning with high accuracy.
In conclusion, according to one embodiment of the present disclosure, the magnetic disc medium has the first part and the second part having different light reflections, and the head includes the first device for detecting reflection of the magnetic disc medium and the second device for performing magnetic recording and playback processes on the magnetic disc medium. Herewith, the second device is able to determine a position for magnetic recording/playback on the magnetic disc medium based on the reflection of the magnetic disc medium detected by the first device. As a result, even if the magnetic disc medium is distorted, it is possible to cause the head to follow the data tracks with high accuracy.
All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority or inferiority of the invention. Although the embodiments of the present disclosure have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
The present application is a continuation application filed under 35 U.S.C. 111(a) claiming benefit under 35 U.S.C. 120 and 365(c) of PCT International Application No. PCT/JP2007/050330, filed on Jan. 12, 2007, the entire contents of which are incorporated herein by reference.
Number | Date | Country | |
---|---|---|---|
Parent | PCT/JP2007/050330 | Jan 2007 | US |
Child | 12489134 | US |