JP2767869B2 - Information track search device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information track search device for searching for a desired information track from a record carrier having a large number of information tracks.

2. Description of the Related Art As a conventional information track search device, a linear tracking system is used to move an optical pickup incorporating a semiconductor laser, a photodetector, and the like from an inner peripheral side to an outer peripheral side of a disk-shaped record carrier, and to form a disk-shaped disk. There is an optical reproducing apparatus that reproduces a signal recorded on a disk-shaped record carrier by rotating the record carrier at a predetermined rotation speed.

The above-mentioned disc-shaped record carrier has a width of 0.6 μm and a pitch of 1.6 μm.
Micro information signal recording tracks of μm are provided spirally or concentrically. The optical pickup converges a light beam generated by a semiconductor laser by an objective lens as a pickup element and irradiates the light onto the above-described track, thereby reading a signal recorded on a disc-shaped record carrier. . For this reason, tracking control is performed on the objective lens so that the light beam is always positioned on the track.

This tracking control obtains a signal corresponding to the positional deviation between the objective lens and the track from the reflected light from the disc-shaped record carrier, and applies this signal to a tracking actuator that moves the objective lens in a direction substantially perpendicular to the track direction. Has been done.

The optical pickup can freely move in the radial direction of the disc-shaped record carrier. Then, the optical pickup is moved in the radial direction of the disc-shaped record carrier by a pickup feed motor or the like.

The disk-shaped record carrier is provided with a large number of tracks, and a search means is indispensable to search for a track on which desired information is recorded.

To search for a desired track on a record carrier, the optical beam is track-jumped and the optical pickup is moved in a direction crossing the track (JP-A-54-92115).

In the continuous track jump, the light beam is track-jumped several times, then the optical pickup is moved in the radial direction of the record carrier by a feed motor or the like, and then the light beam is again track-jumped. .

In a device for recording and reproducing information on a disk-shaped record carrier (hereinafter abbreviated as a disk), it is required that a track on which desired information is recorded can be searched at high speed, and that the device is small and lightweight. In the conventional method of moving an optical pickup having a built-in semiconductor laser or photodetector in the radial direction of a disk by a feed motor or the like, the shape and weight of the optical pickup itself are increased, so that the optical pickup is recorded on the disk. It was difficult to retrieve information at high speed and to downsize the device.

In view of the above, there has been proposed a separation type optical pickup in which optical parts such as a semiconductor laser and a photodetector are separated from an objective lens and a tracking actuator so that the weight of a moving part in a disk radial direction is remarkably reduced (JP-A-59-96880). No.).

FIG. 3 shows a shape diagram of a conventional separation type optical pickup. This will be described below with reference to FIG.

The objective lens 10 is attached to a gantry 13 via a leaf spring 12, and when a current flows through a tracking coil (not shown), the objective lens 10 is driven in the radial direction of the disk. The leaf spring 12 is configured to be easily expanded and contracted in a direction perpendicular to the disk surface and to be hardly expanded and contracted in the radial direction of the disk. Therefore, when the objective lens 10 is driven in the radial direction of the disc, the gantry 13 is driven in the radial direction of the disc by the force of the leaf spring 12.

Problems to be Solved by the Invention In the above-described conventional configuration, the gantry 13 has a sliding bearing 30
And a guide 29 in the radial direction of the disc. Therefore, the weight of the gantry 13 acts as an axial pressure between the slide bearing 30 and the shaft 29, and a relatively large bearing loss occurs between the slide bearing 30 and the shaft 29 due to sliding friction.

As described above, the objective lens 10 and the gantry 13 are connected by the leaf spring 12, and if the gantry 13 has such a loss due to friction, the movement of the objective lens 10 is hindered. This phenomenon acts as a disturbance during a track jump, and makes the track jump unstable.

Since the gantry 13 is driven via the leaf spring 12,
13 starts moving at a timing later than the objective lens 10. Since the mass ratio between the gantry 13 and the objective lens 10 is configured to be small, the acceleration acting on the objective lens 10 in the direction opposite to the direction in which the gantry 13 starts to move due to the acceleration when the gantry 13 starts to move. This acceleration acts as a disturbance during a track jump, and thus makes the track jump unstable.

SUMMARY OF THE INVENTION An object of the present invention is to provide an information track searching apparatus which eliminates the above-mentioned conventional drawbacks, stabilizes a track jump by a separation type optical pickup, and can search a signal on a disk at a high speed.

Means for Solving the Problems In order to achieve the above object, an information track search apparatus of the present invention is provided with a reproducing means for reproducing a signal from an information track on a record carrier and a base in a radial direction of the record carrier. A movable frame is mechanically connected to the record carrier by a support member having a characteristic that is difficult to expand and contract in the radial direction of the record carrier, and a force is generated on the base to move the reproduction position in the radial direction. One moving means, a second moving means for generating a force on the base and moving the gantry in the radial direction,
First and second amplifying means for amplifying an output of the signal generating means for generating a pulse-like signal for moving a reproducing position of the reproducing means to an adjacent track; Add the output signal of the first amplifying means and add the output signal of the second amplifying means to the second moving means to move the reproducing position of the reproducing means to an adjacent track or to change the reproducing position of the reproducing means. It is configured to repeatedly move to an adjacent track.

Operation Since the present invention performs the track jump by adding the output signal of the signal generating means to the first moving means and the second moving means by the above-described configuration, even if a frictional force is generated on the gantry, it can overcome it. Track jump can be performed stably. Also, since a track jump can be performed by generating an equal acceleration in the first moving means and the second moving means, disturbance due to a difference in acceleration between the first and second moving means is eliminated, and the track jump is stabilized. Can be done.

Hereinafter, an information track search device of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals are used for the same components as those shown in FIG.

FIG. 1 is a block diagram showing one embodiment of the present invention.
Embodiments of the present invention will be described below with reference to the drawings.

The disk 1 is attached to a rotation shaft of a motor 2 and is rotated at a predetermined rotation speed. A light beam 4 generated from a light source 3 such as a semiconductor laser is collimated by a coupling lens 5, passes through a polarizing beam splitter 6, a 波長 wavelength plate 7, is reflected by a total reflection mirror 8, and is reflected by an objective lens 10. Irradiates the disk 1 with.

The reflected light 9 of the light beam 4 reflected by the disk 1 passes through the objective lens 10, is reflected by the total reflection mirror 8, passes through the quarter-wave plate 7, is reflected by the polarization beam splitter 6, and is detected by the photodetector 11. Irradiated above.

The objective lens 10 is attached to the pedestal 13 of the actuator via two leaf springs 12, and a coil (not shown)
When a current is applied to the disk, the coil can be moved in a direction perpendicular to the surface of the disk 1 by the electromagnetic force received by the coil.

The focus of the objective lens 10 is controlled so that the light beam 4 radiated on the disk 1 is always in a predetermined convergence state. However, since the focus is not directly related to the present invention, the description of the focus control is omitted.

The light source 3, the coupling lens 5, the polarization beam splitter 6, the quarter-wave plate 7, and the photodetector 11 are all fixed to a frame (omitted) of the apparatus.

A base 28 is attached to this frame. Trestle
The disc 13 is guided in the radial direction of the disc 1 by a shaft 29 mounted on the base 28.

The gantry 13 is provided with a total reflection mirror 8 and a coil 14. When a current flows through the coil 14, the coil 14 generates a force on the base 28, and the coil 14 and the total reflection mirror 8 are integrated with the gantry 13. As a result, the disk 1 can be moved in the radial direction. The leaf spring 12 is configured to easily expand and contract in a direction perpendicular to the surface of the disk 1 and hardly expand and contract in the radial direction of the disk 1. Therefore, when the gantry 13 moves in the radial direction of the disk 1, the objective lens 10 receives the force via the leaf spring 12 and moves in the radial direction of the disk 1.

A coil 15 is attached to the objective lens 10, and when a current is applied to the coil 15, the coil 15 generates a force on the base 28, so that the objective lens 10 can be moved in the radial direction of the disk 1. I have.

Therefore, when the objective lens 10 moves, the gantry 13 receives a force via the leaf spring 12, and the gantry 13 moves in the radial direction of the disk 1 by this force.

The photodetector 11 has a two-part structure, and its output is input to amplifiers 16 and 17, respectively.

The signals of the amplifiers 16 and 17 are input to the differential amplifier 18, respectively. The differential amplifier 18 outputs a signal corresponding to the difference between the two signals. The signal of the differential amplifier 18 is a signal indicating a positional shift between the light beam 4 converged on the disk 1 and the track, that is, a track shift signal.

The signal of the differential amplifier 18 is supplied to a phase compensating circuit 19 for compensating the phase of the tracking control system, a switch 20, and an adding circuit.
21, coil 14 via drive circuit 22 for power amplification
And a coil 15 via an addition circuit 23 and a drive circuit 24 for power amplification. Therefore, the objective lens 10 is driven in accordance with the signal of the differential amplifier 18, and tracking control is performed so that the light beam 4 converged on the disk 1 is always positioned on the track. Switch 20
Is for disabling the tracking control in the open state.

Next, a track jump operation will be described. When a track jump command is input to the input device 31, the microcomputer (μ-CPU) 26 opens the switch 20 to disable the tracking control, and causes the jump pulse generation circuit 27 to output a pulse signal.

The output signal of the jump pulse generation circuit 27 is amplified by an amplification circuit (AMP) 33, and then applied to the coil 15 via an addition circuit 23 and a drive circuit 24, and further amplified by an amplification circuit (AMP) 32 and added to the addition circuit. 21, applied to the coil 14 via the drive circuit 22. This allows the objective lens 10
The gantry 13 is moved by one track in the radial direction of the disk 1, and a track jump is performed.

When the objective lens 10 moves in the radial direction of the disk 1,
The differential amplifier 18 outputs a signal of the light beam on the disk 1 crossing the track, and the crossing detector 25 outputs the differential amplifier.
Compare the voltage of the 18 output signals with the internal reference voltage.
Outputs the digitized track crossing signal.

The microcomputer 26 detects the acceleration and deceleration timings of the objective lens 10 and the gantry 13 based on the output of the crossing detector 25.

The gantry 13 is mounted on the disk 1 by the slide bearing 30 and the shaft 29.
Are guided in the radial direction. Therefore, the weight of the gantry 13 acts as an axial pressure between the slide bearing 30 and the shaft 29,
Therefore, a relatively large bearing loss occurs between the sliding bearing 30 and the shaft 29 due to sliding friction. As described above, the objective lens 10 and the gantry 13 are connected by the leaf spring 12 and mutually exert a force. If the gantry 13 has such a frictional loss, the movement of the objective lens 10 is thereby caused. Is inhibited. This phenomenon makes the track jump unstable.

In the present embodiment, the output signal of the jump pulse generation circuit 27 is applied to both the objective lens 10 and the gantry 13 to generate a force on both the objective lens 10 and the gantry 13 against the base 28 to perform a track jump. Therefore, even if there is a loss due to friction as described above, the track jump can be stably performed sufficiently against the loss.

Further, according to the present invention, the gantry 13 is not driven by an indirect force via the leaf spring 12, but is driven directly by the same signal as the signal for driving the objective lens 10. 10 acceleration and deceleration timings can be aligned.

On the other hand, the acceleration generated in the objective lens 10 and the gantry 13 is affected by the current-force sensitivity of the coils 14 and 15. Therefore, when the current-force sensitivities of the coil 14 and the coil 15 are largely different from each other, the amplification factors of the amplifier circuits 32 and 33 are adjusted so that the waveform of the output signal of the jump pulse generation circuit 27 as shown in FIG. By adjusting the high value A, the magnitude of the acceleration generated in the objective lens 10 and the gantry 13 can be made uniform.

As described above, according to this embodiment, at the time of a track jump,
Since the timing for accelerating and decelerating the objective lens 10 and the gantry 13 and the magnitude of the acceleration generated in the objective lens 10 and the gantry 13 can be made uniform, the conventional objective lens 10
The disturbance generated due to the difference between the acceleration generated in the frame 13 and the acceleration generated in the gantry 13 can be eliminated, and the track jump can be stably performed.

Further, according to the present embodiment, since the track jump is performed by driving both the objective lens 10 and the gantry 13, the thrust at the time of the track jump increases, and the track jump can be performed at a high speed.

The present invention is not limited at all by the examples. For example,
In a device for recording and reproducing information on a magnetic disk, by using the present invention for a magnetic head that reads information from a track on which information is recorded, a stable and high-speed track jump can be performed, and information can be searched at high speed. It is possible to provide a magnetic disk device capable of performing the above.

According to the present invention, the gantry and the objective lens are connected to each other by a leaf spring configured to easily expand and contract in the direction perpendicular to the surface of the disk, and to expand and contract in the radial direction of the disk. In an optical pickup configured to be able to move in the radial direction of a disk by generating a force on a base, an output signal of a jump pulse generation circuit is applied to driving means for both the objective lens and the gantry, so that an objective lens is provided. And the gantry both generate a force on the base and make a track jump, so even if a large frictional force is acting on the gantry, it is possible to stably perform a track jump against it sufficiently it can.

If the magnitude of the acceleration of the mount and the objective lens is different,
The acceleration of the gantry causes a change in the acceleration of the objective lens, and the track jump becomes unstable.According to the present invention, not only can the acceleration and deceleration timings of the gantry and the objective lens during the track jump be aligned, Since the magnitude of the acceleration generated between the gantry and the objective lens during the track jump can be made uniform, the disturbance caused by the difference in acceleration between the gantry and the objective lens can be eliminated, and the track jump can be performed stably. it can.

According to the present invention, since the track jump is performed by driving both the objective lens and the gantry, the thrust at the time of the track jump is increased, and the track jump can be performed at a high speed.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining an embodiment of an information track searching device according to the present invention, FIG. 2 is a waveform diagram of an output signal of a jump pulse generating circuit, and FIG. 3 is a shape of a conventional separated optical pickup. FIG. DESCRIPTION OF SYMBOLS 1 ... Disc, 2 ... Motor, 3 ... Light source, 4 ... Light beam, 10 ... Objective lens, 11 ... Photodetector, 12 ... Leaf spring, 13 ... Stand, 14,15 ... Coil, 18 ... Differential amplifier, 21,23 ... Addition circuit, 22,24 ... Drive circuit, 27 ... Jump pulse generation circuit, 28 ... Base, 29 ... Axis, 30 ...
Sliding bearing, 34 …… Fixed optical bench.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 21/08 G11B 7/085

Claims (2)

(57) [Claims] 1. A reproducing means for reproducing a signal from an information track on a record carrier and a mount movable in a radial direction of the record carrier with respect to a base extend and contract in a radial direction of the record carrier. A first moving unit that is mechanically connected to a support member having a characteristic that is hard to generate, generates a force on the base, and moves a reproduction position of the reproduction unit in the radial direction, and a force on the base. And a second moving means for moving the gantry in the radial direction, a signal generating means for generating a pulse-like signal for moving a reproducing position of the reproducing means to an adjacent track, It has first and second amplifying means for amplifying the output, adding the output signal of the first amplifying means to the first moving means and outputting the output of the second amplifying means to the second moving means. A signal is added to set the reproduction position of the reproduction means to an adjacent track. Information track retrieval apparatus characterized by being configured to perform repeated movement of the adjacent tracks of the playback position or the playback unit moves into click. 2. The amplitude of the output signal of the signal generating means is adjusted so that the acceleration generated by the first moving means in the first and second amplifying means is substantially equal to the acceleration generated by the second moving means. 2. The information track search device according to claim 1, wherein the information track searching device is configured to amplify and perform a continuous track jump one by one or one by one.