JPH11259881A - Optical disk drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive optical disk drive which gains quick access. SOLUTION: The optical disk drive consists of a spindle motor (disk driving means) 55 which drives and rotates a disk 53, a guide 57 which is provided across the tracks of the disk 53, a carriage 59 which engages the guide 57 movably, an objective 63 which is provided to the carriage 59 through a leaf spring (suspension) 61 and floats from the disk 53 or approaches the disk 53 with an air flow through the rotation of the disk 53 and converges a light beam on the disk, and a fixed optical system 70 which transmits the light beam to the objective 63.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus that irradiates a disk with a light beam and performs at least data writing, out of data reading and data writing.

[0002]

2. Description of the Related Art Next, a conventional example will be described with reference to the drawings.
FIG. 2 is a diagram showing an example of a conventional optical disk device.

In FIG. 1, a carriage 5 is movably engaged with first and second guides 1 and 3 arranged in a direction crossing tracks of a disk M which is driven to rotate by disk drive means (not shown). ing.

[0004] A first magnetic circuit 7 is provided along the first guide 1, and a second magnetic circuit 9 is provided along the second guide 3. The first magnetic circuit 7 includes an outer yoke 11
, An inner yoke 13 and a magnet 15 provided on the outer yoke 11, and a magnetic gap G1 is formed between the magnet 15 and the inner yoke 13.

Similarly, the second magnetic circuit 9 includes an outer yoke 17, an inner yoke 19, and a magnet 21 provided on the outer yoke 17, and the magnet 21 and the inner yoke 1
9, a magnetic gap G2 is formed.

On one side of the carriage 5, a first track coil 25 having a portion crossing the magnetic flux of the magnetic gap G1 of the first magnetic circuit 7 is provided. On the other side, a first magnetic circuit 9 is provided. The second track coils 27 each having a portion crossing the magnetic flux of the magnetic gap G2 are provided.

Accordingly, the first magnetic circuit 7 and the first track coil 25, and the second magnetic circuit 9 and the second track coil 27, respectively, form a moving coil type linear motor.

A lens holder 31 provided with an objective lens 29 is mounted on the carriage 5 via a leaf spring (suspension) not shown. Carriage 5
On the upper side, the third and fourth lens holders 31 are sandwiched.
Are provided.

The third magnetic circuit 33 comprises a yoke 37 and a magnet 39, and the fourth magnetic circuit 35 also comprises a yoke 41 and a magnet 43. A first focus coil 45 having a portion crossing the magnetic flux of the third magnetic circuit 33 is provided on one side surface of the lens holder 31, and a portion crossing the magnetic flux of the fourth magnetic circuit 35 is provided on the other side surface. Second focus coils 47 are provided, respectively.

Next, the operation of the optical disk apparatus having the above configuration will be described. When an electric current is applied to the first and second track coils 25, 27, the first and second track coils 25, 2
7 generates a thrust for moving the carriage 5 along the first and second guides 1, 3, and the carriage 5 moves along the first and second guides 1, 3 to perform tracking.

First and second focus coils 45, 4
When current flows through the first and second focus coils 4,
At 5, 47, a thrust is generated in a direction to move the lens holder 31 toward and away from the disk M. The lens holder 31 approaches and separates from the disk M while bending the leaf spring.
Focusing is performed.

[0012]

However, in the optical disk apparatus having the above structure, a mechanism for focusing the objective lens (a mechanism for moving the objective lens 29 toward and away from the disk M) is provided on the carriage 5. ing. That is, the third and fourth magnetic circuits 33, 35 and the first
And a second focusing coil 45, 47.

Since heavy electromagnetic components are mounted on the carriage 5, there is a problem that high-speed access is not possible. In general, in such an optical disk device, when the lens holder 31 performs focusing, which is a high-speed control, higher-order resonance may occur, which may hinder the focusing servo.

In order to prevent this higher-order resonance, the drive sources (the first and second focusing coils 45 and 47), the driven lens holder 31, and the objective lens 29 must act as rigid bodies. Costly.

The present invention has been made in view of the above problems, and a first object of the present invention is to provide an optical disk device capable of high-speed access. A second object of the present invention is to provide a low-cost optical disk device.

[0016]

According to a first aspect of the present invention, there is provided an optical disk apparatus for irradiating a disk with a light beam and writing data at least, wherein the disk is driven to rotate. A driving means, a guide provided in a direction crossing the track of the disk, a carriage movably engaged with the guide, and a carriage provided on the carriage via a suspension;
The air flow generated by the rotation of the disk causes the disk to levitate from the disk, approach the disk, perform one of the operations, and focus the light beam on the disk. An optical disc device comprising an optical system for feeding.

When the disk drive rotates the disk, a positive pressure or a negative pressure is generated between the disk and the objective lens. Whether the positive pressure or the negative pressure is generated is determined by the shape of the objective lens.

When a positive pressure is generated, the objective lens floats up to a certain distance from the disk. When a negative pressure is generated, the objective lens approaches the disc until a certain interval is reached.

With the objective lens kept at a constant distance from the disk, at least data is read into the disk by the light beam from the optical system focused by the objective lens.

When the disk driving means stops driving the disk, the negative pressure / positive pressure generated between the disk and the objective lens disappears, and the objective lens returns to the original position by the elastic restoring force of the suspension. Return.

According to the optical disk device having such a configuration, the objective lens is kept at a fixed position with respect to the disk by rotating the disk, so that focusing is not required.

Therefore, heavy electromagnetic parts for focusing the objective lens are not required, the weight of the carriage can be reduced, and high-speed access is possible. In addition, since focusing which is a high-speed control is not required, a measure for preventing higher-order resonance is not required, and cost can be reduced.

According to a second aspect of the present invention, there is provided an optical disc apparatus, wherein the optical system according to the first aspect of the present invention is provided with a correction means for correcting a light beam sent to the carriage.

By driving the correction means, variations in disks (errors in disk thickness, surface accuracy (flatness)) and temperature compensation of the objective lens are performed. According to a third aspect of the present invention, there is provided an optical disk device wherein the objective lens according to the first or second aspect is made of molded plastic.

By using a molded plastic for the objective lens, the weight of the carriage can be reduced and the cost can be reduced.

[0026]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a configuration diagram of a main part of an optical disk device according to an embodiment of the present invention.

In FIG. 1, a spindle motor 55 is provided on a base 51 as a disk drive for driving the disk 53 to rotate. On the base 51, a guide rail 57 is provided as a guide disposed in a direction crossing the track of the disk 53, and a carriage 59 is movably engaged with the guide rail 57.

The carriage 59 is moved along the guide 57 by driving means (not shown) such as a linear motor having a magnetic circuit and a coil as shown in FIG.

The carriage 59 is provided with an objective lens 63 via a leaf spring 61 as a suspension which is flexible in the direction of the disk 53. The objective lens 63 according to the present embodiment is made of molded plastic, and is formed so that any one of a positive pressure and a negative pressure is generated between the objective lens 63 and the disk 53 by an air flow generated by the rotation of the disk 53.

Whether a positive pressure or a negative pressure is generated depends on the shape of the objective lens 63. When a positive pressure is generated, the objective lens 63 is moved so that the objective lens 63 floats with respect to the disk 53 until a predetermined interval is reached.
A spring constant of 1 is set.

Similarly, when a negative pressure is generated, the spring constant is set so that the objective lens 63 approaches the disk 53 until a certain interval is reached. Base 51
Is provided with a fixed optical system 70. The fixed optical system 70 includes a semiconductor laser diode (LD) 71 that emits a laser beam, a collimator lens 73 that uses a divergent laser beam emitted from the LD 71 as a parallel laser beam,
A prism beam splitter (prism) 75 that partially transmits and partially reflects the laser beam, a correction lens 77 movably provided in the optical axis direction of the laser beam transmitted through the prism 75, and a laser beam And a correction lens driving means 79 driven in the optical axis direction. By moving the correction lens 77 in the optical axis direction, variations in the disk 53 and temperature correction of the LD 71 are performed.

Further, the base 51 is provided with signal processing means 81 for generating a reproduction signal and a tracking error signal from the laser beam reflected by the prism 75 among the return laser beams reflected by the disk 53.

A correction lens 77 is provided on the carriage 59.
There is provided a mirror 85 for reflecting the laser beam from the mirror in the direction of the objective lens 63. Next, the operation of the above configuration will be described.

When the spindle motor 55 rotates the disk 53, the distance between the disk 53 and the objective lens 63 is
When a positive pressure or a negative pressure is generated, the objective lens 63
3 are held at regular intervals.

The operation for reading data and the operation for writing data will be separately described below. (Reading of Data) The laser beam emitted from the LD 71 of the fixed optical system 70, converted into a parallel beam by the collimator lens 73, and transmitted through the prism 75 is subjected to variation of the disk 53 and temperature correction of the LD 71 by the correction lens 77, and the carriage Go to 59.

The laser beam entering the carriage 59 is
The light is reflected by the mirror 85 and focused on the disk 53 by the objective lens 63. The laser beam reflected by the disk 53 and superimposed with the data recorded on the disk 53 is reflected by the prism 75 via the objective lens 63, the mirror 85, and the correction lens 77, and the signal processing means 81 converts the data into an electric signal. Into a reproduced signal.

The signal processing means 81 also generates a tracking error signal, and performs tracking based on this signal. (Writing of data) When a laser beam on which write data is superimposed is emitted from the LD 71 of the fixed optical system 70, this laser beam is converted into a parallel beam by the collimator lens 73, transmitted through the prism 75, and disc-shaped by the correction lens 77. The dispersion of 53 and the temperature of the LD 71 are corrected, and the light goes to the carriage 59.

The laser beam entering the carriage 59 is
The light is reflected by the mirror 85, condensed on the disk 53 by the objective lens 63, and data is written on the disk 53.

The laser beam reflected by the disk 53 is
The light is reflected by the prism 75 via the objective lens 63, the mirror 85, and the correction lens 77, and a tracking error signal is generated by the signal processing means 81. Tracking is performed based on this signal.

According to the optical disk apparatus having such a configuration, the objective lens 63 is kept at a fixed position with respect to the disk 53 by the rotation of the disk 53, so that focusing is not required.

Accordingly, heavy electromagnetic parts for focusing the objective lens 63 are not required, the weight of the carriage 59 can be reduced, and high-speed access is possible. or,
Focusing, which is high-speed control, is not required, so that measures for preventing higher-order resonance are not required, and cost can be reduced.

Further, the correction lens 77 and the correction lens 77
Is provided in the optical axis direction of the laser beam.
(Error in thickness of disk 53, surface accuracy (flatness)), and temperature compensation of objective lens 63 can be performed.

Further, by making the objective lens 63 of molded plastic, the weight of the carriage 59 can be reduced.
Further, costs can be reduced. Note that the present invention is not limited to the above embodiment. In the above embodiment,
The optical system that sends the laser beam to the objective lens 63 is a base 5
1, the fixed optical system 70 provided on the carriage 70
The present invention can also be applied to an optical disk device having a configuration in which all optical systems are provided.

[0044]

As described above, according to the first aspect of the present invention, the disk is provided on the carriage via the suspension, and the airflow generated by the rotation of the disk causes the disk to float from the disk or approach the disk. Either operation is performed, and the objective lens that focuses the light beam on the disk is provided.The objective lens is kept at a fixed position with respect to the disk by the rotation of the disk. Become.

Accordingly, heavy electromagnetic parts for focusing the objective lens are not required, the weight of the carriage can be reduced, and high-speed access is possible. In addition, since focusing which is a high-speed control is not required, a measure for preventing higher-order resonance is not required, and cost can be reduced.

According to the second aspect of the present invention, by driving the correction means, variations in the disk (error in the thickness of the disk, surface accuracy (flatness)) and temperature compensation of the objective lens are performed.

According to the third aspect of the present invention, the weight of the carriage can be reduced and the cost can be reduced by using a molded plastic for the objective lens.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical disk device according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a conventional optical disk device.

[Explanation of symbols]

 53 Disk 55 Spindle Motor (Disk Starting Means) 59 Carriage 61 Leaf Spring (Suspension) 63 Objective Lens 70 Fixed Optical System (Optical System)

Claims (3)

[Claims] 1. An optical disk device for irradiating a disk with a light beam and writing data at least, comprising: a disk drive means for driving the disk to rotate; and a guide provided in a direction crossing tracks of the disk. A carriage movably engaged with the guide; and a carriage provided on the carriage via a suspension. The air flow generated by the rotation of the disk causes the disk to float or approach the disk. An optical disc apparatus, comprising: an objective lens for converging a light beam on the disc, and an optical system for sending the light beam to the objective lens. 2. The optical disk device according to claim 1, wherein said optical system is provided with a correction means for correcting a light beam sent to said objective lens. 3. The optical disk device according to claim 1, wherein the objective lens is molded plastic.