KR20070077722A - Nfr optical pick-up system to be controlled by multi-axis actuator - Google Patents

Abstract

An optical pickup for near-field recording is provided to prevent a servo from being unstable when a lens and a disc are contacted with each other due to an abrupt surface vibration of the disc. An optical apparatus for near-field recording is controlled by a multi-axis actuator. The optical apparatus comprises a base(100), a holder(103) fixed to the base(100), a bobbin(107) for fixing an SIL(Solid Immersion Lens), a spring wire(130) connected from the bobbin(107) to the holder(103), and a magnetic driver. The magnetic driver has a focus coil(120), a tracking coil(122), and a tilt coil(125). The magnetic driver moves the bobbin(107) in a focus direction, a tracking direction, or a tilt direction.

Description

Near-field optical pickup device controlled by multi-axis drive actuatorsNF Optical Pick-up system to be controlled by multi-axis actuator

1 is a perspective view of a four-axis drive actuator for SIL according to an embodiment of the present invention,

2 is a front view of the bobbin in FIG. 1, FIG.

3 is a block diagram of a circuit portion of an optical pickup 4-axis driving actuator according to an embodiment of the present invention;

4 is an exploded perspective view of an optical pickup four-axis driving actuator according to another embodiment of the present invention;

5 is a front view of the bobbin in FIG. 3;

6 is a block diagram of a circuit portion of an optical pickup 4-axis driving actuator according to another embodiment of the present invention;

7 is a view schematically illustrating a method of winding each coil of a four-axis drive actuator for optical pickup according to another embodiment of the present invention.

{Description of the symbols for the main parts of the drawing}

10: Spring wire for focus coil 13: Focus coil start terminal

20: Spring wire for tracking coil 23: Starting coil tracking terminal

30: spring wire for tilt coil 33: start of tilt coil

40: common ground wire 43: common ground terminal

50: control input generator 53: comparator

55 low pass filter

The present invention relates to a near field optical pickup device controlled by a multi-axis drive actuator. In particular, in the near field recording method, when contact with a lens occurs due to sudden disc exhaustion during gap servo, the servo becomes unstable. The present invention relates to a device capable of securing servo stability by continuously generating a high frequency excitation signal in the tilt direction of a three-axis or four-axis actuator.

Conventional CD / DVD recording methods are widely used in media and data storage by securing a storage capacity of hundreds of megabytes to several gigabytes by using track pitches of several tens to tens of millimeters.

This CD / DVD is characterized by an actuator system that maintains a certain distance from the recording medium for accessing track information of several tens to several millimeters.However, in order to increase the storage capacity, the surface of the actuator and the recording medium may be nano-scaled. Near field recording ('NFR') technology to maintain and servo is introduced.

In general, the low speed and low cost actuators used in optical disc drives are only focused and tracking direction servos, and three axes (focusing, tracking, and radial tilt) with the addition of axis rotation in the radial direction for high speed response are realized. Actuator is used.

In the case of the actuator used in the near field recording system, the high-speed response does not have a big problem, and a 2-axis actuator can be used as in a conventional low-cost optical disk drive, but the actuator and the disk are shown even when a small amount of disk isolation is present in nanoscale control. May issue a conflict.

If a perfect servo is implemented, such a collision can be prevented, but an impact between an actuator and a disc may occur at any time due to an impact or a drop from the outside of the drive, and in this case, the actuator may be shaken at an initial position, causing the servo to become unstable. Occurs.

In addition, when the actuator collides with the disk, the actuator is rotated finely, and the servo becomes unstable. In this case, there is a problem that the servo must be restarted at a remote field in order to start the servo.

The present invention has been made to solve the above problems, the object is to provide a proximity action optical pickup actuator that can solve the problem of the West becomes unstable when the lens and the disk contact due to sudden disk isolation, etc. There is.

In order to achieve the above object, the near-field optical pickup device controlled by the multi-axis drive actuator of the present invention includes a base; A holder fixed to the base; Bobbins to fix SIL; A spring wire connected from the bobbin to the holder; And a magnetic drive unit including a focus coil, a tracking coil, and a tilt coil to move the bobbin in a focus direction, a track direction, or a tilt direction.

In the present invention, a focus coil start terminal, a tracking coil start terminal and a tilt coil start terminal are respectively provided separately, and the focus coil, tracking coil and tilt coil end terminals are commonly grounded with each other, and the focus coil and tracking coil And a circuit unit for applying a voltage to the tilt coil.

The magnetic driving unit includes a first magnet and a second magnet disposed to face each other with the bobbin interposed therebetween, an outer yoke installed at the base and fixing the first magnet, and the first magnet in a position facing the first magnet. An inner yoke installed at a base to guide the bobbin, a tracking coil wound around the sidewall of the bobbin at a position opposite to the first magnet, a focus coil wound around the outside of the bobbin, and the second magnet Preferably, the coil is made of a tilt coil wound on the side wall of the bobbin at an opposite position.

In the present invention, the tilt coil is preferably separated into a coil for tangential and radial tilt compensation.

In the present invention, it is preferable that the coil for tangential tilt compensation receives an excitation signal having a frequency within 1 to 100 Hz for tangential tilt control.

In the present invention, it is preferable that the coil for radial tilt compensation receives an excitation signal having a frequency within 1 to 100 Hz for radial tilt control.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In adding reference numerals to components of the following drawings, it is determined that the same components have the same reference numerals as much as possible even if displayed on different drawings, and it is determined that they may unnecessarily obscure the subject matter of the present invention. Detailed descriptions of well-known functions and configurations will be omitted.

1 is a perspective view of a multi-axis drive actuator according to an embodiment of the present invention.

Referring to FIG. 1, the wire type optical pickup actuator includes a base 100, a holder 103 fixed to the base 100, a bobbin 107 fixing the SIL 105, and the bobbin 107. ) And a magnetic drive unit for moving the bobbin 107 in a track direction, a focus direction, or a tilt direction.

The magnetic driving unit is installed on the base 100 and the first magnet 110 and the second magnet 112 opposed to each other with the bobbin 107 therebetween to fix the first magnet 110. An inner yoke 117 and an inner yoke 117 installed on the base 100 at a position facing the first magnet 110 to guide the bobbin 107 and the bobbin 107. A focus coil 120 wound around the outside of the coil, a tracking coil 122 wound around a side wall of the bobbin 107 at a position opposite to the first magnet 115, and the second magnet 112. It consists of a tilt coil 125 wound on the side wall of the bobbin 107 in the viewing position.

1 and 2, the wire for focus coil 130 connecting the start terminal 127 and the end terminal 129 of the focus coil 120 to the bobbin 103; A tracking coil wire 135 connecting the start terminal 132 and the end terminal 133 of the tracking coil 122 to the bobbin 103, and the start terminal 137 and the end of the tilt coil 125. Tilt coil wire 140 for connecting the terminal 139 to the bobbin 103. These wires 130, 135, 140 not only serve as electric wires for applying current to each of the focus coil 120, the tracking coil 122, and the tilt coil 125, but also the holder 103. The bobbin 107 is also connected to support the bobbin 107 driven by the magnetic driving unit.

Typically, the actuator wire is composed of four pairs of focus coil spring wires 130 and tracking coil spring wires 135, and the holder supports the bobbin 107 up to the tilt coil spring wires. When elastically connected to 103, the fixing force for supporting the bobbin 107 is increased by that, which is constrained in the movement of the bobbin 107. Therefore, in view of such a problem, the tilt coil wire 140 is directly coupled to the rear wall of the holder 103 via the holder 103 directly.

The bobbin 107 is driven by the four-axis drive in the focus direction (A), the track direction (B), the tangential tilt direction (C), and the radial tilt direction (D). Looking at the circuit configuration of such a four-axis drive actuator is shown in FIG. This shows the voltage application circuit of each coil. Here, only the focus coil 120 will be described, but the remaining tracking coil 122 and the tilt coil 125 are configured in the same manner.

Referring to FIG. 3, the circuit for focus coil 120 includes a control input generator 145, a comparator 147, a start terminal 127 of the focus coil to which a driving voltage is input from the comparator 147, and It consists of an end terminal 129 through which current flows through the focus coil 120. Since this circuit is also applied to the tracking coil 122 and the tilt coil 125, a total of six wires are required.

4, the same reference numerals as in FIG. 1 denote the same components. Here, the wire connecting the holder 103 and the bobbin 107 is provided with the focus coil spring wire 10, the tracking coil spring wire 20, and the tilt spring wire 30, respectively. . In addition, the focus coil 120, the tracking coil 122, and the tilt coil 125 are commonly grounded, so that one more spring wire 40 for common ground is added, and thus a total of four wires are included.

Accordingly, as shown in FIG. 5, the wire includes a start terminal 13 of the focus coil 120, a start terminal 23 of the tracking coil 122, and a start terminal 33 of the tilt coil 125. Each having a common ground terminal 43 for each common ground thereof. Each of the start terminals 13, 23, 33, and the common ground terminal 43 may be variously disposed in addition to the arrangement as shown in FIG. 5.

On the other hand, the configuration of the circuit portion 45 to operate the above-described electrical configuration is as shown in FIG. In this case, only the voltage is applied to the focus coil 120. The voltage supplied from the control input generator 50 passes through the filter 55 through the comparator 53 and the noise is removed while the focus is removed. It is supplied to the coil start terminal 13. Such a circuit is also configured in the tracking coil 122 and the tilt coil 125. Here, the filter 55 is a low pass filter that removes high frequency noise.

 Looking at the winding method of each coil according to this, as shown in Figure 7, the start coil 13 for the focus coil, the start terminal 23 for the tracking coil and the start coil 33 for the tilt coil are provided, respectively, these start Starting from the terminals 13, 23, 33, each coil is wound in a predetermined position. Then, the ends of the wound focus coil 120, tracking coil 122, and tilt coil 125 are grounded in common to the common ground terminal 44. And wires are connected from the start terminals 13, 23, 33 and the common ground terminal 44 to the holder 103 to form four spring wires 10, 20, 30 and 40. will be.

Looking at the electrical action in the above configuration, the voltage is applied from the control input generator 50 and the voltage is applied to each of the corresponding wires 10, 20, 30 through the comparator 53 and the filter 55 When supplied, current flows through each of the coils 120, 122 and 125. Then, Fleming's left-hand rule is applied between the current flowing through the coils 120, 122 and 125 and the first and second magnets 110 and 112, so that the bobbin 107 is focused. (A), track direction (B), tangential tilt direction (C) and radial tilt direction (D).

As such, the four-axis driving actuator for optical pickup according to the present invention has four springs as in the past even when the focus coil 120 and the tracking coil 122 are provided with a tilt coil 125 for correcting the tilt error. It is possible to operate by wire alone.

Therefore, since the bobbin moves in the focusing direction, the track direction and the tilting direction more freely than when it is connected with six spring wires or four spring wires and two tilting coil wires, control is easy.

8 is a graph showing a tilt direction excitation signal according to an embodiment of the present invention.

Referring to FIG. 8, when the disk and the actuator collide with each other and the disk surface is not parallel, the actuator transmits an excitation signal as shown in FIG. 8 to continuously generate fine shaking of several nanometers or less in the radial or tangential direction, thereby causing the actuator to be short-lived. Restore to its original state. The excitation signal has a period of several tens to hundreds of microseconds, and it is preferable that the excitation signal is also 1 to 2V.

As described above, it has been described with reference to the preferred embodiment of the present invention, but those skilled in the art various modifications and changes of the present invention without departing from the spirit and scope of the present invention described in the claims below I can understand that you can.

As described above, according to the present invention, by using a three-axis or four-axis drive actuator in the near-field storage system, there is no need to install a separate tilt device in the pick-up, thereby making it easy to configure the entire system and reduce the cost There is an advantage.

In addition, by applying the continuous high frequency voltage to the actuator, it is possible to compensate for the minute angle change of the actuator due to the collision of the disk and the actuator, which may occur due to disk isolation or disturbance, thereby reducing the servo time and improving the servo efficiency. Can bring

In case of using 4-axis drive actuator, it is possible to solve the tilt between SIL and disk recording surface which can occur due to the characteristics of the system which needs to do the gap servo of several tens of nanometers. do.

Claims (6)

Base; A holder fixed to the base; Bobbins to fix SIL; A spring wire connected from the bobbin to the holder; And a focusing coil, a tracking coil, and a tilting coil, wherein the bobbin moves the bobbin in a focusing direction, a tracking direction, or a tilting direction. The focus coil start terminal, the tracking coil start terminal, and the tilt coil start terminal are separately provided, respectively, and the focus coil, the tracking coil, and the tilt coil end terminals are commonly grounded to each other. And a circuit unit for applying a voltage to the tracking coil and the tilt coil, wherein the near field optical pickup device is controlled by the multi-axis driving actuator. The magnet as claimed in claim 1, wherein the magnetic drive unit includes a first magnet and a second magnet disposed to face each other with the bobbin interposed therebetween, an outer yoke installed at the base to fix the first magnet, and the first magnet to the first magnet. An inner yoke installed at the base at a position facing the opposite side to guide the bobbin, a tracking coil wound at the bobbin side wall at a position opposite to the first magnet, a focus coil wound at the outside of the bobbin, And a tilt coil wound on a side wall of the bobbin at a position facing the second magnet. 3. The near field optical pickup apparatus of claim 1 or 2, wherein the tilt coil is separated by a coil for tangential and radial tilt compensation. 5. The near field optical pickup of claim 4, wherein the coil for tangential tilt compensation receives an excitation signal having a frequency within 1 to 100 Hz for tangential tilt control. Device. 5. The near field optical pickup apparatus of claim 4, wherein the coil for radial tilt compensation receives an excitation signal having a frequency within 1 to 100 kHz for radial tilt control.

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