JPH08221768A - Optical disk device - Google Patents

Abstract

PURPOSE: To home move a pickup module at an appropriate speed by providing a drive current switching means for switching linear motor drive currents stepwise. CONSTITUTION: A carriage driver 11 supplies current to a linear motor, a servo control means 13 servo-controls the operation of the linear motor and outputs a synchronous signal based on the result of servo control. A drive current switching means 14 switches currents supplied from the carriage driver 11 to the linear motor in stages depending on the existence of a synchronous signal or a reading signal from the optical pickup module 12 of an optical reading means. Also, the drive current switching means 14 performs control so as to supply a specified drive current 15 from the carriage driver 11 to the linear motor and then performs control so as to supply a drive current 15 bigger by one stage when there is no synchronous signal 17 or a reading signal from the optical pickup module 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device having a driving device for driving an optical pickup in which a linear motor and an optical reading section are integrally formed.

[0002]

2. Description of the Related Art In recent years, an optical disk device represented by a CD-ROM drive device has been used as a key component in the field of multimedia, including personal computers.
It has been used for home game machines and electronic publishing.

A conventional optical disk device will be described below as a CD-RO.
The M drive device will be described as an example.

FIG. 3 is a perspective view of a carriage drive device (hereinafter, simply referred to as an optical pickup module) of a conventional CD-ROM drive device. In the figure, the optical pickup module includes a spindle motor 1 for rotating a disk, a laser diode, an objective lens,
An optical pickup 5 including a light receiving element and the like is mounted, and a carriage 2 that slides on a guide rail 3 to move in the radial direction of the disk and a linear motor 4 that drives the carriage 2 are provided. is there. The linear motor 4 is composed of a plate-shaped permanent magnet 40 that constitutes the field thereof and a coil 41 that constitutes an armature (armature) arranged on the carriage 2 side.

The operation of the optical pickup module configured as described above will be described below. FIG. 4 is a flowchart of the initialization position setting operation of the conventional CD-ROM drive device.

In FIG. 4, first, the CD-ROM drive device is placed at a position where the synchronous pull-in of servo control can be performed in order to perform focus, track control, etc. as one of the initialization operations when the power is turned on or a disc is inserted. An initialization position setting operation for moving the carriage 2 (hereinafter abbreviated as home move) is performed.

In this home move, the TOC (Table) recorded in the lead-in area near the innermost circumference of the disk is moved by moving the carriage 2 to the innermost circumference (spindle motor side) of the movable range of the carriage 2. of C
ontents) information is accessed (step 1).

When starting this home move, since it is not known where the carriage 2 is located within the carriage possible range, first, by supplying an appropriate carriage drive current, the carriage 2 is moved in the innermost circumferential direction (see FIG. 3). Drive to the spindle motor side).

In order to drive the carriage 2 supported by the guide rails 3, a linear motor 4 is used, which enables a high-speed movement with a thin type. Therefore, the linear motor 4 and the optical reading unit are integrated into an optical system. The structure of the pickup 5 is adopted.

The carriage 2 that has started the home move by the carriage drive current moves to a position where servo pull-in such as focus and track control is possible (step 2).

Therefore, the CD-ROM drive device confirms whether or not the carriage 2 has arrived at the initialization position by focusing on information pits or trying track counting, and performs servo control such as focus and track control. If the synchronous pull-in is possible, the servo pull-in is completed (step 3), and if the servo pull-in is not completed, the home move operation is continuously repeated by the carriage drive current (step 2).

CD-ROM when servo pull-in is completed
The original operation of the drive device is started (step 4).

[0013]

However, it is technically difficult to make the magnetizing forces of the magnets forming the linear motor 4 uniform, and the current-operating sensitivity characteristics of the linear motor 4 vary, and the guide The frictional force of the rail 3 also varies due to processing accuracy and the adhesion of dirt over time. Therefore, when a constant carriage drive current is applied to the linear motor 4, a difference occurs in the driving force received from the linear motor 4 depending on the position of the carriage 2, resulting in a difference in the moving speed of the carriage 2.

Further, when the CD-ROM drive device itself is installed at an inclination, it is affected by the mass of the carriage 2 itself as compared with the case where the CD-ROM drive device is installed in a horizontal state. The movement speed of 2 may be increased (decelerated conversely).

Particularly, it is difficult to make a home move (for example, the guide rail 3 where the magnetic force of the linear motor 4 is weak).
The friction is large, the CD-ROM drive device is installed at an inclination such that the inner peripheral side of the optical pickup module is upward, etc.), the carriage 2 is surely moved to the TOC area near the innermost peripheral portion of the disc. If the carriage drive current is defined as the carriage drive current during home move, the moving speed of the optical pickup module becomes too fast under the opposite conditions, and when the carriage 2 reaches the innermost circumference, the carriage is installed in the innermost circumference. It will collide with the stopper that is holding.

Since the carriage 2 is composed of light emitting / receiving elements, optical components such as an objective lens and a mirror, which require high accuracy, an excessive impact due to a collision adversely affects the optical system of the optical pickup 5. It had a problem of fear.

The present invention has been made to solve the above problems, and provides an optical disk device capable of performing a home move at an appropriate speed regardless of mechanical variations in pickup modules and differences in installation conditions. The purpose is to do.

[0018]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and includes optical reading means for optically reading information recorded on an optical disk,
An optical disk device having a carriage for moving an optical reading means in a radial direction of an optical disk, in which a carriage driver for supplying a current to a linear motor and a servo control for servo operation of the linear motor are provided. Servo control means for outputting a synchronization signal according to the control result and drive current switching means for stepwise switching the drive current supplied from the carriage driver to the linear motor depending on the presence or absence of the synchronization signal or the read signal by the optical reading means. The drive current switching means, once the carriage driver once controls to supply a predetermined drive current to the linear motor, and if there is no synchronization signal or a read signal by the optical reading means,
The present invention is characterized in that the carriage driver is controlled to supply a drive current that is larger by one step to the linear motor.

[0019]

In the optical disk device configured as described above, the drive current of the linear motor is gradually changed from a weak value to a strong value depending on the presence or absence of the read signal detected according to the movement of the carriage during the home move. I decided to go
The home move operation can be executed at the optimum speed.

That is, first, the home move and the servo pull-in are confirmed by the first stage drive current, and if the servo pull-in cannot be performed, the home move and the servo pull-in are confirmed by the second stage drive current. be able to.

By operating as described above, the home move can be performed at an appropriate speed regardless of the mechanical variation of the pickup module, the variation of the sensitivity of the linear motor, and the difference in the installation state. When it reaches the inner circumference, it does not collide with the stopper installed at the innermost circumference, so that the home move operation can be stably performed without giving an excessive impact to the carriage.

[0022]

An embodiment of the present invention will be described below with reference to the drawings. A CD-ROM drive device will be described as an example of the optical disc device. Further, the configuration of the optical pickup module is the same as that of the conventional one shown in FIG.

FIG. 1 is a block diagram of an optical disk device according to an embodiment of the present invention. In the figure, the optical disk device according to the present embodiment is provided with a carriage driver 11 for supplying a drive current 15 to the linear motor 4, and an optical pickup module in which the linear motor 4 and the optical pickup 5 are integrated (see FIG. 3). 12) and the optical pickup module 12, the focus servo control of the optical system and the tracking servo control of the carriage drive system are performed, and when the synchronous pull-in control is completed, the servo control means 13 outputs the pull-in result. And a drive current switching means 14 for switching the drive current 15 of the carriage driver 11 to increase when the pull-in control of the servo control means 13 is not completed.
The servo control means 13 outputs a focus servo control signal 16 for the optical system, and the optical pickup module 12 outputs a sync signal 17 for focus servo control and tracking servo control. Further, the servo control means 13 outputs a pull-in result signal 18 for synchronous pull-in control to the drive current switching means 14. A drive current switching signal 19 is output from the drive current switching means 14 to the carriage driver 11.

FIG. 2 is a flowchart of a home move in one embodiment of the present invention. The operation of the optical disc device configured as described above will be described with reference to the drawings.

First, as in the conventional optical disk device, when the power is turned on or the disk is replaced, the TOC information recorded in the lead-in area near the innermost circumference of the disk is accessed.

Therefore, in order to home move the carriage 2, the drive current switching means 14 sets an initial value of a predetermined drive current 15 to the carriage driver 11 (step 11).

The carriage driver 11 drives the linear motor 4 of the optical pickup module 12 with the set drive current 15 to perform a home move, and moves the carriage 2 in the inner peripheral direction (step 12).

At this stage, it is still unknown whether or not the carriage 2 actually starts moving, or where it is located. Therefore, the servo control means 13 monitors whether or not a focus or tracking optical pit signal is obtained from the disk surface (step 13). Since the reading speed of the optical system is much faster than the movement of the carriage 2, it is not necessary to set the viewing time after the movement control of the carriage 2.

If the optical pit signal is not obtained as a result of the circular inspection, it is judged that the carriage 2 has not moved or is located in an area where no information is recorded in the vicinity of the outermost circumference of the disc. Jump to.

On the other hand, if the optical pit signal is obtained, it is determined that the carriage 2 is located in the area where the information of the disc is recorded, and the process proceeds to the next step 14. This is because if the optical pit signal is obtained, the rotation control of the spindle motor 1, the tracking control of the carriage 2, and the focus control of the optical system can be performed, so that the servo control means 13 sends the focus servo control signal 16 to the optical pickup module 12. This is because the servo pull-in can be confirmed by checking whether or not the sync signal 17 is obtained by sending (step 14).

When the servo pull-in is completed by the above control, the optical disk device starts a normal home move to access the TOC information at the innermost circumference of the disk and starts the original operation of the optical disk device (step 1).
6). At this time, the servo control means 13 outputs the pull-in result signal 18, and the drive current switching means 14 continues the drive current 15 initially set based on the pull-in result signal 18.

Even if the complete home move is not completed in step 14 or step 16, if the carriage 2 can be moved to the position where the optical pit signal is obtained, the movement control of the carriage 2 can be started in step 14. As described above, the same applies to step 16.

If the drive current 15 is too weak to perform the home move, or if the drive current 15 is located in the area on the outermost circumference of the disc where no information is recorded, no optical pit signal is obtained, and therefore, Servo pull-in cannot be completed. In this case, since the servo control means 13 does not output the pull-in result signal 18, the drive current switching means 14 outputs the drive current switching signal 19 and the carriage driver 11 a signal for increasing the drive current 15 by one step. (Step 15), home move is performed again, and focus / tracking monitoring is continued (step 13).

In this way, the home move is performed by sequentially increasing the drive current 15 step by step until the servo pull-in is completed. In one embodiment of the present invention, an upper limit is set for the amount of increase in current as a safety measure for control, and the amount of increase in current in one step can be selected to be, for example, 10%. It goes without saying that the condition (1) is appropriately set based on the mass of the carriage and the driving force of the linear motor 4.

As described above, by controlling the drive current 15 of the linear motor 4 to be increased stepwise,
It is possible to perform a stable and appropriate home move with respect to variations in the sensitivity of the linear motor 4 and changes in posture without giving an excessive impact to the carriage 2.

[0036]

As described above, according to the present invention, by providing the drive current switching means for gradually increasing the carriage drive current during the home move from the weak value stepwise, the mechanical variation of the pickup module and the linear motor can be improved. Since the home move can be performed at an appropriate speed regardless of variations in sensitivity and differences in installation state, when the carriage reaches the innermost circumference, it may collide with the stopper installed on the innermost circumference. Therefore, the home move operation can be stably performed without giving an excessive impact to the carriage.

[Brief description of drawings]

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

FIG. 2 is a flowchart of a home move according to an embodiment of the present invention.

FIG. 3 is a perspective view of a carriage drive device of a conventional CD-ROM drive device.

FIG. 4 is a flowchart of an initialization position setting operation of a conventional CD-ROM drive device.

[Explanation of symbols]

 1 spindle motor 2 carriage 3 guide rail 4 linear motor 11 carriage driver 12 optical pickup module 13 servo control means 14 drive current switching means 15 drive current 16 focus servo control signal 17 synchronization signal 18 pull-in result signal 19 drive current switching signal

Front page continuation (72) Inventor Hiroyuki Gondo 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. An optical disc apparatus comprising: an optical reading unit for optically reading information recorded on an optical disc; and a driving unit for moving the optical reading unit in a radial direction of the optical disc. The drive means includes a drive circuit that supplies a current to the drive source, servo control means that servo-controls the operation of the drive source and outputs a synchronization signal according to the result of the servo control, the synchronization signal or the optical reading means. Drive current switching means for stepwise switching the current supplied from the drive circuit to the drive source according to the presence or absence of a read signal by the drive circuit, and the drive current switching means temporarily switches from the drive circuit to the drive source. After controlling the supply of a predetermined current, if there is no synchronization signal or the read signal, a current of one step larger value is applied to the drive circuit. Optical disc apparatus, characterized by a control to be supplied to the driving source from. 2. The optical disk device according to claim 1, wherein the drive source is a linear motor having a carriage as an armature. 3. The optical disk device according to claim 1, wherein the drive current switching means has a predetermined upper limit value for the current value to be switched.