JPH02249146A - Information track retriever - Google Patents

Abstract

PURPOSE:To stabilize track jump by a separated type optical pickup and to retrieve a signal on a disk at high speed by performing the track jump by adding the signal of a signal generating means on first and second moving means. CONSTITUTION:The output signal of a jump pulse generation circuit 27 is added on a coil 15 via an adder circuit 23 and a driving circuit 24, and also, is added on a coil 14 via an adder circuit 21 and a driving circuit 22, and an objective lens 10 and a frame 13 are moved by one track in the radius direction of the disk 1, then, the track jump is performed. When the objective lens 10 is moved in the radius direction of the disk 1, the signal in which a light beam on the disk 1 traverses the track is outputted to a differential amplifier 18, and a traverse detector 25 outputs a track traverse signal in which the signal of the differential amplifier 18 is compared. A microcomputer 26 detects the timing of acceleration and deceleration of the objective lens 10 and the frame 13 by the output of the traverse detector 25. In such a way, the track jump can be stably performed at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an information track retrieval device for retrieving a desired information track from a record carrier having a large number of information tracks.

2. Description of the Related Art A conventional information track retrieval device moves an optical pickup containing a semiconductor laser, a photodetector, etc. in a linear tracking manner from the inner circumference side to the outer circumference side of a disk-shaped record carrier. There is an optical reproducing device that reproduces a signal recorded on a disc-shaped record carrier by rotating the carrier at a predetermined number of rotations.

On the disk-shaped record carrier mentioned above, a width of 0.6 μm and a pitch of 1
．． Information signal recording trunks as small as 6 μm are provided in a spiral or concentric pattern.

Optical pickups read out signals recorded on a disc-shaped record carrier by converging a light beam generated by a semiconductor laser using an objective lens, which serves as an off-pit amplifier element, and irradiating it onto the aforementioned trunk. ing. 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 adds this signal to a tracking actuator that moves the objective lens in a direction approximately perpendicular to the track direction. It is being done.

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

A disk-shaped record carrier is provided with a large number of tracks.
A search means is essential to search for a track in which desired information is recorded.

When searching for a desired track on a record carrier, a light beam is caused to jump across the track and an optical pickup is moved across the track (
JP-A No. 54-92115).

Continuous track jumping is performed by first making the light beam jump several times, then moving the optical pickup in the radial direction of the record carrier using a feed motor, etc., and then making the light beam jump the track again. .

2. Description of the Related Art Devices for recording and reproducing information on disk-shaped record carriers (hereinafter referred to as disks) are required to be able to quickly search for tracks on which desired information is recorded, and to be small and lightweight. In the conventional method in which an optical pickup with a built-in semiconductor laser or photodetector is moved in the radial direction of the disk using a feed motor, etc., the size and weight of the optical pickup itself becomes large, so It was difficult to search for information quickly and to miniaturize the device.

Therefore, a separated optical pickup has been proposed in which optical components such as a semiconductor laser and a photodetector are separated from an objective lens and a tracking actuator to significantly reduce the weight of the moving part in the disk radial direction (Japanese Patent Application Laid-Open No. 1983-1982). 96880
Publication No.).

FIG. 4 shows a shape diagram of a conventional separation type optical pickup. This will be explained below using FIG.

The objective lens 1o is attached to a pedestal 13 via a leaf spring 12, and a tracking coil) Ly (not shown)
When a current flows through, 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 difficult to be expanded and contracted in the radial direction of the disk.

Therefore, when the objective lens 10 is driven in the radial direction of the disk, the pedestal 13 receives a force via the leaf spring 12 and is driven in the radial direction of the disk.

Problems to be Solved by the Invention In the above conventional configuration, the pedestal 13 has a sliding bearing 3.
o and axis 29 in the radial direction of the disk. Therefore, the weight of the stand 13 is the weight of the bearing 30 and shaft 29.
act as axial pressure during the period, so that the plain bearing 30
A comparatively large bearing causes a loss due to sliding friction between the shaft 29 and the shaft 29.

As mentioned above, the objective lens 1o and the pedestal 13 are connected by the leaf spring 12, and if there is any loss due to such friction in the pedestal 13, the movement of the objective lens 1o will be inhibited. This phenomenon acts as a disturbance during a track jump, making the track jump unstable.

Further, since the pedestal 13 is driven via the leaf spring 12, the pedestal 13 starts to move at a later timing than the objective lens 10. Since the mass ratio of the mount 13 and the objective lens 10 is configured to be small, the mount 1 is attached to the objective lens 1o.
The acceleration when the frame 13 starts moving causes acceleration to act in the opposite direction to the direction in which the pedestal 13 starts moving. This acceleration acts as a disturbance during a track jump, making the track jump unstable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an information track retrieval device that eliminates the above-mentioned conventional drawbacks, stabilizes track jumps by a separate optical pickup, and allows high-speed retrieval of signals on a disk.

Means for Solving the Problems In order to achieve the above object, the information track retrieval device of the present invention comprises a reproducing means for reproducing a signal from a record carrier;
a pedestal movable in the radial direction of the record carrier with respect to the base; a support member having one end fixed to the pedestal and supporting the reproduction position of the reproduction means in a state movable in the radial direction; a first moving means that generates a force against the base and moves the reproduction position in the radial direction; and a second moving means that generates a force against the base and moves the mount in the radial direction. and a signal generating means for generating a signal for performing a track jump, and is configured to perform a track jump by adding the signal of the signal generating means to the first moving means and the second moving means. It is something.

Function: With the above-described configuration, the present invention adds the output signal of the signal generating means to the first moving means and the second moving means to perform a track jump, so that even if frictional force is generated on the mount, it can be overcome. It is possible to stably perform a track jump, because it is possible to perform a track jump by generating equal acceleration in the first and second means of transport, so the acceleration of the first and second means of transport can be Disturbances caused by differences are eliminated and track jumps can be performed stably.

Embodiment Hereinafter, the information track retrieval device of the present invention will be explained in detail with reference to the drawings. In addition, in the numbers used to explain the drawings,
Components that are the same as those shown in FIG. 4 are designated by the same reference numerals.

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

The disk 1 is mounted on the rotating shaft of a motor 2 and rotated at a predetermined number of rotations. A light beam 4 generated from a light source 3 such as a semiconductor laser 9 .
, passes through a wavelength plate 7, is reflected by a total reflection mirror 8, and is irradiated onto the disk 1 by an objective lens 1o.

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 % wavelength plate 7, is reflected by the polarization beam fritter 6, and is sent to the photodetector 11. is illuminated above.

The objective lens 10 is attached to the actuator mount 13 via two leaf springs 12, and when a current is passed through the coil /L/ (not shown), the coil receives an electromagnetic force that is perpendicular to the surface of the disk 1. It is configured so that it can move in any direction.

Further, the objective lens 10 is focus-controlled so that the light beam 4 irradiated onto the disk 1 is always in a predetermined convergence state, but since it is not directly related to the present invention, a description of the focus control will be omitted. .

10. The light source 3, the coupling lens 5, the polarizing beam splitter 6, the % wavelength plate 7, and the photodetector 11 are all fixed to the frame (not shown) of the apparatus.

A base 28 is attached to this frame. The pedestal 13 is guided in the radial direction of the disk 1 by a shaft 29 attached to the base 28.

A total reflection mirror 8 and a coil 14 are attached to the pedestal 13. When a current flows through the coil 14, the coil 14 generates a force against the base 28, and the coil 14 and the total reflection mirror 8 are integrated with the pedestal 13. It is configured so that it can move in the radial direction of the disk 1.

The leaf spring 12 is configured to be easily expanded and contracted in a direction perpendicular to the disk 1 and difficult to expand and contract in the radial direction of the disk 1. Therefore, when the pedestal 13 moves in the radial direction of the disk 1, the objective lens 10 receives a 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 1o,
When a current is applied to the coil /l/15, the coil 15 generates a force against the base 28, and the objective lens 1o can be moved in the radial direction of the disk 10.

Therefore, when the objective lens 10 moves, the mount 13 is moved by the plate spring 1.
2, and this force causes the pedestal 13 to move in the radial direction of the disk 10.

The photodetector 11 has a two-divided structure 9, and its output is input to amplifiers 16 and 1γ, respectively.

The signals from the amplifiers 16 and 1 are input to a differential amplifier 18, respectively. Differential amplifier 18 outputs a signal according to the difference between both signals. The signal from the differential amplifier 18 is a signal representing a positional deviation between the optical beam 4 focused on the disk 1 and the track, that is, a track deviation signal.

The signal from the differential amplifier 18 is sent to the coil 14 via a phase compensation circuit 19 for compensating the phase of the tracking control system, a switch 20, an adder circuit 21, a drive circuit 22 for power amplification, and an adder circuit 23, The power is applied to each coil 15 via a drive circuit 24 for power amplification. Therefore, the objective lens 1o is driven according to the signal from the differential amplifier 18, and tracking control is performed so that the light beam 4 focused on the disk 1 is always located on the track. The switch 20 is for disabling tracking control when it is open.

Next, the track jump operation will be explained.

When a track jump command is input to the input device 31, the microcomputer 26 opens the switch 20 to disable 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 sent to the adder circuit 23.
, is added to the cari/l/15 via the drive circuit 24, and is added to the cari/l/15 via the adder circuit 212 and the drive circuit 22.
/14, the objective lens 1o and the mount 13 are moved by one track in the radial direction of the disk 10, and a track jump is performed.

When the lens 10 moves in the radial direction of the disk 1, a signal indicating that the optical beam 13 on the disk 1 crosses the track is output to the differential amplifier 18, and the crossing detector 26 outputs a signal indicating that the optical beam 13 on the disk 1 crosses the track. Outputs a track crossing signal by comparing the signals.

The microcomputer 26 detects the timing of acceleration and deceleration of the objective lens 10 and the pedestal 13 based on the output of the transverse detector 25.

The pedestal 13 is guided in the radial direction of the disk 1 by a horizontal bearing 30 and a shaft 29. Therefore, the weight of the frame 13 acts as axial pressure between the slide bearing 30 and the shaft 29, and therefore, a loss occurs in a relatively large bearing due to sliding friction between the slide bearing 30 and the shaft 29. As mentioned above, the objective lens 10 and the mount 13 are connected to the plate spring 12.
, and exert forces on each other. Therefore, if there is any loss due to such friction in the mount 13, the movement of the objective lens 10 will be hindered. This phenomenon makes track jumps unstable.

In this embodiment, a track jump is performed by applying the output signal of the jump pulse generation circuit 27 to both the objective lens 1o and the mount 13, thereby generating force on the base 28 in both the objective lens 10 and the mount 13. Because
Even if there is loss due to friction as described above, it is possible to sufficiently resist this loss and perform track jumps stably.

Furthermore, according to the present invention, the mount 13 is not driven by an indirect force via the leaf spring 12, but is driven directly by the same signal as the signal that drives the objective lens 1o.
The timing of acceleration and deceleration of the objective lens 10 can be aligned.

On the other hand, the acceleration generated in the objective lens 1o and the pedestal 13 is affected by the current force sensitivity of the carp/L/14 and the carp/l/15. Therefore, carp/l/14 and carp)v
15, the jump pulse generation circuit 27 and the adder circuit 21 are connected as shown in FIG.
．． Amplifying circuits 32 and 33 are provided between the jump pulse generating circuits 23 and 23 to adjust the wave height of the output signal of the jump pulse generating circuit 27 as shown in FIG. I can do it.

15, ＼.

As described above, according to this embodiment, the timing of accelerating and decelerating the objective lens 1Q and the pedestal 13 and the magnitude of the acceleration generated in the objective lens 10 and the pedestal 13 can be made equal during track jump, so that unlike conventional It is possible to eliminate the disturbance caused by the difference between the acceleration generated in the objective lens 10 and the acceleration generated in the mount 13,
Can perform track jumps stably.

Further, according to this embodiment, since the track jump is performed by driving both the objective lens 10 and the mount 13, the thrust force during the track jump increases, and the trunk jump can be performed at high speed.

The present invention is not limited in any way by the examples. For example, in a device that records and reproduces information on a magnetic disk, by using the present invention in a magnetic head that reads information from a track on which information is recorded, it becomes possible to perform stable and high-speed track jumps, allowing information to be transmitted at high speed. We can provide a magnetic disk device that can search for.

Effects of the Invention In the present invention, the pedestal and the objective lens are connected by a leaf spring that is configured to easily expand and contract in the direction perpendicular to the surface of the disk, but difficult to expand and contract in the radial direction of the disk. In an optical pickup configured to generate force against the base to move the disk in the radial direction, the objective lens is Both the mount and the mount generate force against the base to perform a track jump, so even if a large frictional force is acting on the mount, it is possible to sufficiently resist the force and perform a stable trunk jump. can.

If the acceleration of the mount and the objective lens are different, the acceleration of the objective lens will vary depending on the acceleration of the mount.
Track jumps become unstable, but according to the present invention,
Not only can the timing of the acceleration and deceleration of the mount and the objective lens be aligned during a track jump, but also the magnitude of the acceleration generated in the mount and the objective lens during a track jump can be made to be the same. Disturbances caused by different lens accelerations can be eliminated, allowing stable trunk jumps.

Further, according to the present invention, since the track jump is performed by driving both the objective lens and the mount, the thrust at the time of the track jump increases, and the track jump can be performed at high speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining one embodiment of the information track search device of the present invention, FIG. 2 is a block diagram for explaining another embodiment of the present invention, and FIG. 3 is a jump pulse generation circuit. FIG. 4 is a plan view showing the shape of a conventional separated optical pickup. 1...disc, 2...motor, 3...
...Light source, 4...Light beam, 10...Objective lens, 11...Photodetector, 12...
Leaf spring, 13... Frame, 14° 15... Coil, 18... Differential amplifier, 21.23...
Addition circuit, 22.24...Drive circuit, 27...
...Jump H/L/S generating circuit, 28...Base, 29...Shaft, 30...Sliding bearing, 3
4...Fixed optical bench.

Claims (2)

[Claims] (1) A reproduction means for reproducing a signal from above a record carrier, a mount movable in the radial direction of the record carrier with respect to a base, one end of which is fixed to the mount, and a reproduction position of the reproduction means is controlled. a support member that supports the radially movable state; a first moving means that generates a force against the base and moves the playback position in the radial direction; a signal generating means for generating a signal for performing a track jump; and a signal generating means for generating a signal for performing a track jump; An information track search device characterized in that it is configured to perform a track jump by adding a signal from a signal generating means. (2) The output signal of the signal generating means is configured so that the acceleration generated by the first moving means and the acceleration generated by the second moving means are approximately equal to perform a track jump. An information track search device according to claim (1).