CN1111845C - Slider for optical disc data storage system - Google Patents

Abstract

An optical disc data storage system (10) includes an optical disc (12) having a data side. A drive arm (24) having a distal end may be selectively positioned radially proximate to the data plane. The sensing element (30) is carried on a slider (20), which is coupled to the end of the actuator arm (24). The slider (20) includes an air bearing surface (56), and the sensing element (30) includes a fiber optic mesa adjacent to the air bearing surface (56). The fiber optic mesa (54) is spaced from the data plane, thereby preventing contact between the data plane and the mesa structure (54).

Description

slider for optical disc storage system

Background of the Invention

The present invention relates generally to optical disc data storage systems. More particularly, the present invention relates to a slider used in an optical head gimbal assembly of an optical head gimbal assembly.

Optical data storage disk (disc) systems are a promising technology for storing large amounts of data. Data is accessed by focusing a laser beam onto the data surface of the disc and detecting the light reflected or emitted from the data surface.

Typically, in optical storage systems, data is in the form of physical or magnetic marks carried on the surface of the disc that can be detected with reflected laser light. Several different optical disc technologies are known in the art. For example, compact discs are currently used to store digital data such as computer programs or digitized music. Typically, compact discs are permanently recorded during manufacture. Another type of optical system is a "write once read many (WORM)" system, where a user can permanently write information on a blank disc. It is desired to provide an erasable system such as phase change and magneto-optical (M-O) systems. By sensing changes in reflectivity, phase change systems detect data. M-O systems read data by measuring the rotation of the polarization of incident light due to the storage medium.

High density optical recording, especially near-field recording (ie, M-O or phase change systems) typically requires an optical head omnidirectional assembly (OHGA) for carrying the sensor device on the data surface of the optical medium. OHGA includes a slider that "flies" close to the data surface of the disc as the disc spins at high speeds. An actuator is used to radially position the slider on the disk surface. US Patent No. 5,497,359 provides a slider used in an optical disc data storage system.

Optical disc data storage systems using the "near field" (or evanescent field) include a "solid immersion lens (SIL)". Such a near-field technique is described in U.S. Patent 5,125,750 entitled "Optical Recording System Employing a Solid Immersion Lens" issued to Corle et al. on June 30, 1992 and on March 5, 1996. US Patent 5,497,359 entitled "Optical Disc Data Storage System with Radiation-Transparent Air-Bearing Slider" issued to Mamin et al. A typical SIL structure includes a hemispherical lens cover on the top of the slider and an optical table structure on the air bearing side of the slider. The optical mesa must be in close proximity to the data side of the disc so that they are near-field optically coupled. Usually this is on the order of less than a few wavelengths.

Summary of Invention

The present invention provides a slider having a land that is protected from contact with an optical disc data storage system. In an optical disc data storage system, an optical disc includes a data side. A drive arm having a distal end is selectively positioned radially adjacent the data plane. A sensing element including a light source is used to sense information. A controller coupled to the actuator arm and the sensing element is used to position the actuator arm and sense information on the data plane via the sensing element. A slider coupled to the end of the actuator arm carries the sensing element. The slider includes a top surface, and an air bearing surface adapted to move adjacent to the data surface as the disk rotates. The table top is on the air cushion surface. An inventive aspect of the present invention is that the air bearing surface includes a raised portion. The optical table is spaced from the raised portion at a certain interval in a direction away from the data surface, thereby preventing contact between the data surface and the optical table. Another inventive aspect of the present invention is that it includes pitching the slider so that the table does not touch the data surface.

Brief description of attached drawings

Figure 1 is a schematic diagram of an optical storage system according to the invention.

Figure 2 is a side view of the slider of Figure 1 in accordance with one embodiment of the present invention.

FIG. 3A is a bottom view of a slider according to another embodiment, and FIG. 3B is a side view thereof.

FIG. 4 is a bottom view of a slider having a raised portion according to another embodiment.

5 is a side view of a slider having a raised portion between a track and a land of the slider according to another embodiment.

Figure 6A is a side view and Figure 6B is a bottom view of a slider according to another embodiment, wherein the slope of the slider is used to separate the land from the data surface of the disc.

Detailed description of the preferred embodiment

The present invention relates to optical data storage systems. In particular, the present invention relates to sliders employing optical data storage systems employing near-field (or evanescent field) optical recording techniques, having a slider carrying a sensor head for optical coupling to a data surface, Used to read and/or write data on it. One such optical data storage system employs a slider that carries optical sensing elements proximate to the data side of an optical storage medium, such as an optical disc. A method for A slider designed for optical recording.

When optically recording information using the near field (or evanescent field), the optical sensing element comprises, for example, a solid immersion lens (or SIL) carried on a slider flying over the disk. Such a solid immersion lens is described in US Patent 5,125,750 entitled "Optical Recording System Employing a Solid Immersion Lens". To write a data bit on the disk, a laser passes through a solid immersion lens to heat a small spot on the disk to a temperature above the Curie temperature of the medium. A magnetic coil carried on the air bearing surface of the slider is energized and turns off the laser. When the temperature of the magnetic medium falls below the Curie point, the heating point becomes the desired magnetic orientation.

The solid immersion lens consists of a hemispherical pattern or a lens cover on the top surface of the slider and an optical table on the opposite surface of the air bearing of the slider. An inventive point of the present invention is the recognition that the optical table is a major element in optical recording and that even a small degradation in its optical properties can significantly affect the performance of the system. In typical prior art sliders, no measures are taken to prevent unwanted contact between the land and the data plane. Additionally, in typical prior art systems, particulates may be present on or near the table. These conditions can alter the optical properties of the mesa. The present invention also includes a mesa depression relative to the raised portion extending from the air bearing surface. The raised portion thus ensures that the mesa is permanently separated from the data plane during operation of the optical disc storage system.

Figure 1 is a schematic diagram of an optical recording system 10 employing a slider 20 in accordance with the present invention. System 10 includes an optical disc 12 having a data side carrying optically encoded information. The disc 12 rotates about an axis and is driven by a spindle motor 16 mounted on a base 18 . Slider 20 is positioned adjacent to optical disc 12 and is coupled to drive 22 including armature 24 and a drive motor 26 coupled to base 18 . The slider 20 includes an optical sensor 30 . The optical sensing element comprises a light source/sensor arrangement 32 . Controller 34 is coupled to device 32 , driver 26 and data bus 36 and is used to control the operation of system 10 .

In operation, the optical disc 12 is rotated and the slider 20 is positioned radially along the data surface of the optical disc 12 by the actuator 22 . Controller 34 controls the position of slider 20 so that information can be read from the data side of optical disc 12 by light source/sensor arrangement 32 and information is received and transmitted on data bus 36 .

FIG. 2 is a simplified side view of slider 20 showing sensor element 30 in accordance with the present invention. In the figure, the slider 20 is close to the data surface 48 of the optical disc 12, and the data surface 48 is depicted as a series of unevenness in the figure. In the illustrated embodiment, the sensor element 30 includes a SIL type (Solid Immersion Lens) lens formed by a lens housing 50 and having a bulk of the slider 20 and a conductor 52 formed in the shape of a coil. In accordance with the present invention, conductor 52 is a coil wound around optical table 54 . The slider 20 includes an air bearing surface 56 and a top surface (or facing surface) 58 . The deck 54 is carried on an air bearing surface 56 . Disc 12 rotates in the direction indicated by arrow 60 , so slider 20 has a leading edge 62 and a trailing edge 64 .

In accordance with the present invention, slider 20 shown in FIG. 2 includes a raised portion 70 on air bearing surface 56 that extends in a direction toward data surface 48 . The raised portion 70 serves as an air bearing contact area and extends down a distance d at the end of the land 54 . The illustrated embodiment of slider 20 is an air track 72 . The raised portion 70 presents a contacting island region in which the mesa is recessed from the end of the raised portion 70 in a direction away from the data plane. This construction makes it impossible to damage the table, wear it down, or allow debris to build up on sensitive optical surfaces.

The embodiments presented here can be fabricated using known techniques such as ion beam etching, machining, grinding, chemical etching or deposition processes. The slider air bearing surface 56 is preferably used to interact with the data surface depending on the characteristics of the media. In general, the depression of the mesa structure relative to the end face can be achieved by any suitable technique including physical depression as shown in Figure 2 or a technique that uses the pitch of the air cushion to position the mesa "up" from the air bearing surface. This is achieved by avoiding damage and debris accumulation.

FIG. 3A is a bottom view of a slider 100 according to another embodiment, and FIG. 3B is a side view thereof. In FIGS. 3A and 3B, a sacrificial wear pad 102 on the air bearing surface 56 of the slider 100 is provided. For simplicity, similar elements retain their numbering from FIG. 1 . This design is well suited for very low contact force designs where continuous contact occurs between the data surface 48 and the sacrificial wear pad 102 . Preferably the total wear on the sacrificial wear layer 102 is less than the distance d they are recessed from the wear pad. This design is particularly well suited for many portable applications. Sacrificial pad layer 102 provides raised portions in accordance with the present invention.

FIG. 4 is a bottom view of a slider 120 according to another embodiment. In the embodiment shown in FIG. 4 , wear pad (or raised portion) 112 is located closer to leading edge 62 of air bearing surface 56 . The underlayment forms a triangular support section for stability. However, other configurations are also conceivable and are also within the scope of the present invention.

FIG. 5 is a side view of a slider 130 according to another embodiment. In the embodiment shown in FIG. 5, slider 130 includes wear pads or raised portions 132 positioned between land 54 and track 72 to provide the desired depression d. The embodiment shown in Figure 5 provides a hybrid design in which the air bearing characteristics of the track 72 give the required operating stiffness and allow mechanical resistance to the slider 130 when contact on the sacrificial wear pad 132 occurs. Reduced vibration sensitivity.

6A and 6B are side and bottom views, respectively, of a slider 140 according to another embodiment of the present invention. In the embodiment shown with slider 140 , the pitch of the slider is used to achieve the separation d between land 54 and data plane 48 . In this design, the table top 54 is positioned close to the track 72 . The trailing edge pad 142 provides a minimum separation s at the trailing edge 64 of the slider 140 between the air bearing surface 56 and the data surface 48 . In this embodiment, track 72 and/or trailing pad 142 are provided with raised portions according to the invention. The sliders presented here can be fabricated according to any suitable technique for optical sliders. Additionally, although the invention has been described using solid immersion lens optics, any suitable optic having a mesa or other raised optic coupled to the data plane via the near field may be used.

Although the present invention has been described with respect to preferred embodiments, workers skilled in the art will recognize that various changes may be made in form and detail without departing from the spirit and scope of the invention. Either type of slider design can be used with the present invention. In addition, the position of the raised portion can be considered to avoid contamination effects of particles or accumulation on adjacent mesas.

Claims (13)

1. optical disc data storage system is characterized in that it comprises:

CD, it has a data surface;

Drive arm, it has an end that can radially be positioned at selectively near described data surface;

Sensing element, it comprises a light source;

Controller, it and drive arm and sensing element coupling are used for to the drive arm location, and by the information on the sensing element sensing data face; And

Slider pad, the end coupling of it and drive arm, and carry described sensing element, described slider pad has an end face and an air cushion surface relative with end face, described air cushion surface has an optics table top and at least one bossing, wherein said optical table extends and is suitable for moving near described data surface during when described disc spins to described data surface, described at least one bossing extends to described data surface, when described slider pad is mobile on described data surface, the elongated end of described at least one bossing is than the more close described data surface of the elongated end of described optical table, thereby when described slider pad was mobile on described data surface, described at least one bossing had prevented the contact between described data surface and the described optics table top.

2. optical disc data storage system as claimed in claim 1 is characterized in that, described air cushion surface also comprises at least one air cushion element.

3. optical disc data storage system as claimed in claim 2 is characterized in that, described at least one air cushion element is a track.

4. optical disc data storage system as claimed in claim 3, the position of described track is near the forward position of described slider pad, and the back edge of the close described slider pad in the position of described optics table top, and described at least one bossing is a bossing between described optics table top and described track.

5. optical disc data storage system as claimed in claim 1 is characterized in that, described at least one bossing comprises three bossings that separate with described optics table top.

6. optical disc data storage system as claimed in claim 5, it is characterized in that, the position of two bossings is near the forward position of described slider pad in described three bossings, and the back edge of the close described slider pad in the position of another bossing, described optics table top is between described two bossings and described another bossing near the edge, back near the forward position.

7. optical disc data storage system as claimed in claim 2 is characterized in that, described at least one air cushion element is included in two tracks that described slider pad both sides separate, and described optics table top is between described two tracks.

8. optical disc data storage system as claimed in claim 7 is characterized in that, described track makes described slider pad become a gradient, thereby has increased the interval between described optics table top and the described data surface.

9. optical disc data storage system as claimed in claim 7, it is characterized in that, described at least one bossing be after one along bed course, back along placing along bed course along described slider pad of described back makes to keep minimum interval (s) between the back edge of described slider pad and described data surface.

10. optical disc data storage system as claimed in claim 1 is characterized in that, described system also comprises one around described optics table top coil on every side.

11. optical disc data storage system as claimed in claim 1 is characterized in that, described optics table top is fully near described data surface, thereby permission is by an optical near-field and the coupling of described data surface.

12. optical disc data storage system as claimed in claim 1 is characterized in that, described at least one bossing contacts with described data surface and weares and teares.

13. optical disc data storage system as claimed in claim 1 is characterized in that, the position of described at least one bossing makes broken cutting depart from described optics table top.

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