JPH1091970A - Disc-shaped information recording medium device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the rise time of the moving speed of an optical head, and to shorten the moving time of the optical head to a target position without affecting the life of the motor. To provide an information recording medium device. SOLUTION: A first applied voltage Vs is supplied to a motor 4 until a frequency of a traverse signal TRS counted by a counting means 8a reaches a predetermined frequency PW.
After the frequency of S reaches the predetermined frequency PW, the stationary second applied voltage Vm lower than the first applied voltage Vs is applied to the motor 4.
Is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk-shaped information recording medium device, and more particularly to an improvement in a recording device or a reproducing device corresponding to a disk-shaped information recording medium such as an optical disk or a magneto-optical disk.

[0002]

2. Description of the Related Art For example, a disk recording apparatus or a reproducing apparatus corresponding to a disk-shaped information recording medium such as a CD-ROM (read-only memory using a compact disk) guides light to the disk-shaped information recording medium. And an optical head having an objective lens for returning the return light from the disc-shaped information recording medium to the optical processing system. This optical head is also called, for example, an optical pickup, and is displaced in the radial direction of a disc-shaped information recording medium by a sled mechanism (moving mechanism).

In this type of sled mechanism, it is necessary to move the optical head with respect to the disk-shaped information recording medium at a high speed. As the sled mechanism, for example, a linear motor feed mechanism or a DC motor feed mechanism is employed. ing. The linear motor feed mechanism supplies an appropriate applied voltage to the linear motor while detecting the speed at that time using a dedicated speed detector, and controls the position of the optical head with respect to the disk-shaped information recording medium. In a feed mechanism using a DC motor, a constant voltage is applied to the DC motor.

[0004]

However, a feed mechanism using a linear motor has the drawback that it is expensive and the control system is complicated. In a feed mechanism using a DC motor, control by supplying an applied voltage is easy. FIG.
9 shows the relationship between the applied voltage and the frequency of a traverse signal in a conventional device. The traverse signal is a group of signals obtained when light passing through the objective lens crosses a recording track of a disc-shaped information recording medium. That is, the magnitude of the frequency of the traverse signal represents the moving speed of the optical head. The applied voltage Vm is applied to the DC motor. In this case, the frequency of the traverse signal gradually increases and becomes constant, and when the supply of the applied voltage Vm stops, the frequency of the traverse signal gradually increases. It is going down. The inclination of the frequency of the traverse signal at the time of rising at this time is indicated by θ. When the DC motor is used as described above, the inclination θ at the time of rising is small and the moving amount of the optical head is small, so that the feeding time T1 of the optical head is long. In order to move the optical head at high speed, it is necessary to set the value of the voltage applied to the DC motor high. If the value of the applied voltage to the DC motor is set high, there is a disadvantage that the life of the motor is shortened due to the structure of the DC motor.

Accordingly, the present invention solves the above-mentioned problems, and reduces the rise time of the moving speed of the optical head without using a speed detector. It is an object of the present invention to provide a disc-shaped information recording medium device which does not affect the life of the disc.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to condense light for recording information on a disk-shaped information recording medium or reproducing information from the disk-shaped information recording medium. An optical head having an objective lens, a motor for moving the optical head in the radial direction of the disc-shaped information recording medium, and a motor which is recorded on the disc-shaped information recording medium while the objective lens is fixed to the optical head. Detecting means for detecting a traverse signal obtained through an objective lens when light traverses a recording track, counting means for counting traverse signals, and first means until the frequency of the traverse signal counted by the counting means reaches a predetermined frequency. Is supplied to the motor, and after the frequency of the traverse signal reaches a predetermined frequency, the stationary second voltage is lower than the first applied voltage.
And a control unit for applying the applied voltage to the motor.

In the present invention, the motor moves the optical head in the radial direction of the disc-shaped information recording medium. The detecting means for detecting a traverse signal detects a traverse signal generated when crossing a recording track recorded on a disc-shaped information recording medium. Then, the counting means counts the traverse signal there. Until the frequency of the traverse signal counted by the counting means reaches a predetermined frequency, the voltage applying means supplies the first voltage to the motor. Then, after the frequency of the traverse signal reaches a predetermined frequency, the voltage applying means applies a steady second applied voltage lower than the first applied voltage to the motor. As a result, it is possible to shorten the moving time of the optical head to the target position by increasing the applied voltage only at the time of starting that requires the most driving force for moving the optical head without affecting the motor life. Can be.

[0008]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

FIG. 1 shows a CD-ROM reproducing device which is an example of a disc-shaped information recording medium device of the present invention.
In FIG. 1, a disc-shaped information recording medium 1 is, for example, C
It is a D-ROM that is driven to rotate continuously by a spindle motor 2. The disc-shaped information recording medium 1 is an optical disc such as a CD-ROM, and can be detachably chucked to a chucking section 2b provided on an output shaft 2a of a spindle motor 2. . An optical pickup 3 as an optical head is arranged below the disc-shaped information recording medium 1. Information recorded on the disc-shaped information recording medium 1 can be read through the objective lens 3a of the optical pickup 3. In the optical pickup 3, for example, a light beam output from a semiconductor laser is recorded on the disc-shaped information recording medium 1 from the objective lens 3a via an optical system including a diffraction grating, a beam splitter, a λ / 4 wavelength plate, and the like. The light is condensed on the surface and irradiated as a light spot. A recording track 1a shown in FIG. 2 formed by pits recorded on the disc-shaped information recording medium 1 is
The irradiated light beam is diffracted to return light. This return light is transmitted to the objective lens 3 of the optical pickup 3.
Then, the light is guided to the light receiving unit by the optical system through a, and reproduced information of the pits of the recording track 1a can be obtained.

In order to control the position of the light spot along the focusing direction FCS and the tracking direction TRK,
The objective lens 3a can be moved by the actuator 3b in the focusing direction FCS and the tracking direction TRK. The light amount of the return light detected by the light receiving unit in the optical pickup 3 is converted into an electric signal, and the electric signal is subjected to processing such as arithmetic amplification in the signal processing unit 6, and the signal processing unit 6 has a disk-like shape. A tracking error signal in the tracking direction TRK and a focus error signal in the focusing direction FCS are generated together with information such as music data on the information recording medium 1. Then, the signal processing unit 6 sends the focus error signal FES and the tracking error signal TES to the servo controller 7 and the traverse signal TR
S is sent to the counting means 8a of the control unit 8. This traverse signal TRS is a light receiving portion of the optical head 3 every time the light spot crosses the recording track when the light spot of the laser light is irradiated on the signal surface of the information recording medium 1 through the objective lens 3a of the optical head 3. Is a signal to be sent to the signal processing unit 6.

The reproduction information of the disc-shaped information recording medium 1 obtained by the signal processing unit 6 is sent to the control unit 8 after a predetermined process. The servo controller 7 sends a signal to the actuator 3b of the optical pickup 3 based on the focus error signal FES and the tracking error signal TES from the signal processing unit 6, so that the tracking direction TRK and the focusing direction FCS of the objective lens 3a. Is performed.

The above-described signal processing unit 6 includes the information recording medium 1
The microcomputer 8 has a counting means 8a for counting the traverse signal TRS generated when the traverse signal TRS is generated when the traverse signal TRS crosses the recording track 1a. When the microcomputer 8 attempts to read the recording track 1a shown in FIG. 2, which is the target to which the optical pickup 3a is to move, the microcomputer 8 operates the actuator 3b of the optical pickup 3 and the objective lens 3a sets the target track 1a. If the optical pickup 3a does not reach the target recording track 1a simply by driving the optical pickup 3a by the actuator 3b, that is, the actuator 3b of the objective lens 3a of the optical pickup 3 In this case, the optical pickup 3 itself is fed, and the motor 4 moves in the radial direction R of the disc-shaped information recording medium 1.

When the optical pickup 3 itself is moved in the radial direction R as described above, the tracking servo by the actuator 3b of the objective lens 3a in the optical pickup 3 is temporarily turned off, and the objective lens 3a
To be free in the horizontal direction. And the control unit 8
Sends a command to the servo controller 7 so that the feed motor drive circuit 5 drives the feed motor 4. Simultaneously with this command, if the objective lens 3a remains free in the horizontal direction, the objective lens 3a
Is shifted, the objective lens 3a issues a command to the servo controller 7 to clamp the optical pickup 3. That is, the servo controller 7 sends a so-called midpoint servo control command signal for clamping the objective lens 3a to the actuator 3b of the objective lens 3a. Thereby, when the optical pickup 3a crosses the disc-shaped information recording medium 1, the signal processing unit 6
Traverse signal TRS output by the optical pickup 3
It can be used as a movement signal of That is, the objective lens 3a is fixed to the optical pickup 3.

The control section 8 has the following functions. The control unit 8 is a microcomputer, and the counting unit 8a counts the traverse signal TRS obtained from the signal processing unit 6, which is a detection unit of the traverse signal TRS. As a result of the counting, during the period from the start time t0 in FIG. 3 until the frequency of the traverse signal TRS reaches the predetermined frequency PW, the control unit 8 controls the start applied voltage Vs as the first applied voltage.
Is issued to the servo controller 7 so as to apply. Then, the counting means 8 of the control unit 8
a further monitors the frequency of the traverse signal TRS, and after the frequency of the traverse signal TRS reaches the predetermined frequency PW, the control unit 8 sends the second applied voltage, the steady applied voltage Vm, to the motor 4. A command is issued to the servo controller 7 to apply the voltage. The start applied voltage Vs, which is the first applied voltage, is a voltage lower than the rating of the feed motor (also referred to as a sled motor) 4, for example, about 6V. The steady applied voltage Vm as the second applied voltage is, for example, 5V.

Next, the operation of the above-described disc-shaped information recording medium reproducing apparatus will be described. When the control unit 8 shown in FIG. 1 gives a command to the servo controller 7, the servo controller 7 operates the spindle motor 2 to rotate the disk-shaped information recording medium 1 continuously. On the other hand, the control unit 8
Gives a command to the servo controller 7, and the servo controller 7 gives a necessary drive voltage to the actuator 3b of the optical pickup 3 so that the objective lens 3a
Is fixed to the optical pickup 3.
That is, the objective lens 3a is in a state where it can move in the R direction together with the optical pickup 3. still,
The actuator 3b is of a drive coil type, and may have a tracking coil and a focusing coil. The feed motor drive circuit 5 supplies a drive voltage to the feed motor 4, and the feed motor 4 rotates the feed screw 4a so that the objective lens 3a reaches the target track 1a as shown in FIG. Due to the action of the nut of the optical pickup 3 meshing with the feed screw 4a, the optical pickup 3 moves in the direction of arrow R (for example, outward of the disc-shaped information recording medium 1), and the objective lens 3a moves to the target track 1a. Will be headed to.

When the feed motor drive circuit 5 applies a voltage to the feed motor 4 as described above, the voltage is applied as shown in FIG. That is, the control unit 8 sends a command to the servo controller 7 to cause the feed motor drive circuit 5 to start moving the feed motor 4. The start time at which the optical pickup 3 starts moving is t0 in FIG. 3, and the counting means 8a of the control unit 8 counts the frequency of the traverse signal TRS obtained from the signal processing unit 6 from this start time t0. Until the frequency counted by the counting means 8a reaches the predetermined frequency PW, the control section 8 gives a command to the servo controller 7 so as to supply the movement start applied voltage Vs which is the first applied voltage in FIG. Drive circuit 5
Activate As a result, the feed motor 4 starts at the start time t.
During a time t1 from 0 to the predetermined frequency PW,
The first applied voltage higher than the second applied voltage which is a steady voltage is applied. As a result, the feed motor 4 takes a time t1 from the start time t0 to reach the predetermined frequency PW.
Therefore, the feed motor 4 can move the optical pickup 3 quickly at the time of starting from the time t0 to t1 when the driving force is most needed. Moreover, since the time from the time t0 to the time t1 is, for example, about 30 ms, the life of the feed motor 4 is not affected.

After the frequency of the traverse signal TRS formed by the counting means 8a of FIG. 1 reaches the predetermined frequency PW, the controller 8 gives another command to the servo controller 7 after time t1 to send the signal. Motor drive circuit 5
Causes the feed motor 4 to apply the normal applied voltage Vm, which is the second applied voltage in FIG. Thus, the feed motor 4 can continuously feed the optical pickup 3 in the R direction to position the light spot passing through the objective lens 3a on the target recording track 1a. In order to stop the feed motor 4 and quickly and accurately position the light spot passing through the objective lens 3a on the target track 1a, the motor drive circuit 5 is used as shown in FIG.
By applying a brake pulse in the reverse direction to the feed motor 4 at the time t2. Time t in FIG.
From 1 to t2, for example, the disc-shaped information recording medium 1
Is about 70 to 80 ms when an area of about 1/3 in the radial direction is accessed. By doing so, the total feed time T2 in the embodiment of the present invention shown in FIG. 3 can be shorter than the total feed time T1 in FIG. 6 shown in the conventional example.

Since the life of the feed motor 4 becomes shorter in inverse proportion to the magnitude of the applied voltage, the continuous application of the applied voltage Vs higher than the steady applied voltage significantly increases the life of the feed motor. Will be shorter. However, in the embodiment of the present invention, the frequency of the traverse signal TRS is changed to the predetermined frequency P from the start time t0 for starting the feed motor 4.
Since the first applied voltage is applied only up to the time t1 until the temperature reaches W, there is no adverse effect on the life of the motor. In addition, since the applied voltage is increased between times t0 and t1 when the driving force is most required, the moving time for moving the objective lens 3a to the target recording track 1a can be shortened. Speed rise time can be reduced. That is, the angle θ1 in FIG. 3 can be set larger than the angle θ in FIG. In this case, the dedicated speed detector conventionally used is unnecessary, and the objective lens 3
This can be achieved by performing speed detection by a traverse signal TRS generated when a crosses the track 1a. FIG. 4 shows an example of a device for feeding the optical pickup 3 by a feed screw method. The device example of FIG. 4 shows the information recording medium device of FIG. 1 more specifically, and shows an example of the chucking unit 2b (turntable), the chassis SC, the optical pickup 3, the feed screw 4a, and the like. In this device example, when the motor 4 in FIG. 1 is driven, the feed screw 4a rotates, and the optical pickup 3 is guided along the radial direction R by the guide shaft 4f. FIG. 5 shows an example of a device for feeding the optical pickup 3 by a flat gear feed system.
5 shows a chucking unit 2b (turntable), a chassis SC1, an optical pickup 3, and a spur gear 2.
One example of 00 is shown. In this device example, when the motor 4 is driven, the various gears 201 are rotated, and the spur gears 2 are rotated.
00 moves linearly. Thus, the optical pickup 3 is guided along the radial direction R with the linear movement of the spur gear 200.

The present invention is not limited to the above embodiment. In the above-described embodiment, the description has been given based mainly on the reproducing apparatus for the disc-shaped information recording medium 1. However, the present invention is not limited to this, and when the disc-shaped information recording medium is a recording / reproducing disc, the recording is performed. The present invention can be applied to an apparatus or a recording / reproducing apparatus.

[0020]

As described above, according to the present invention,
When moving the optical pickup from a stationary state at high speed,
For the purpose of shortening the movement time and extending the life of the sled motor, the drive voltage is applied higher than the drive voltage during the movement only during the start of the movement. Thus, by shortening the rise time of the moving speed of the optical head without using a speed detector, the life of the motor can be extended even if the moving time of the optical head to the target position is shortened.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a recording or reproducing apparatus for a disc-shaped information recording medium of the present invention.

FIG. 2 is a diagram showing tracks on the disc-shaped information recording medium of FIG. 1;

FIG. 3 is a diagram showing a correspondence between an applied voltage and a frequency of a traverse signal in the embodiment of the present invention.

FIG. 4 is a diagram showing an example of an apparatus for feeding an optical head by a feed screw method according to the present invention.

FIG. 5 is a diagram showing an example of an apparatus for feeding an optical head by a flat gear feed method according to the present invention.

FIG. 6 is a diagram showing a correspondence between an applied voltage and a frequency of a traverse signal in the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Disc-shaped information recording medium, 1a ... Track, 3 ... Optical pickup (optical head), 3a
..Objective lens (optical lens), 4 ... feed motor (motor), 6 ... signal processing unit (traverse signal detection unit), 8 ... control unit, 8a ... counting unit, Vs
... Start applied voltage (first applied voltage), Vm ... Normal applied voltage (second applied voltage), PW ... Predetermined frequency, TRS ... Traverse signal

Claims (3)

[Claims] 1. An optical head having an objective lens for recording information on a disk-shaped information recording medium and condensing light for reproducing information on the disk-shaped information recording medium; A motor for moving the information recording medium in the radial direction, and a traverse obtained through the objective lens when light crosses a recording track recorded on the disc-shaped information recording medium with the objective lens fixed to the optical head. Detecting means for detecting a signal; counting means for counting the traverse signal; supplying a first applied voltage to the motor until the frequency of the traverse signal counted by the counting means reaches a predetermined frequency; And a control unit for applying a steady second applied voltage lower than the first applied voltage to the motor after the frequency has been reached. Disc-shaped information recording medium device. 2. The disk-shaped motor according to claim 1, wherein the motor has a feed screw rotated by its output shaft, and the optical head is moved in a radial direction of the disk-shaped information recording medium by rotation of the feed screw. Information recording medium device. 3. The disc-shaped information according to claim 1, further comprising a spur gear linearly moved by driving a motor, wherein the optical head is moved in a radial direction of the disc-shaped information recording medium by the linear movement of the spur gear. Recording media device.