JP2560808Y2 - Light head - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head used in an optical recording / reproducing apparatus for reproducing information on a recording medium or recording / reproducing or recording / reproducing / erasing information on a recording medium. It relates to the brake device at the time of the search.

[0002]

2. Description of the Related Art As an optical recording / reproducing apparatus, an apparatus such as an optical disk for optically reproducing information on concentric or spiral tracks formed on a disk has already been put to practical use.

FIG. 4 shows the configuration of a conventional basic optical head of this kind.

In the optical head shown in FIG. 4, an objective lens 101 for irradiating a laser beam emitted from a laser light source (not shown) onto a recording medium and an optical unit 102 having an actuator for slightly moving the objective lens in a focus direction. Is mounted on the head base 100.

[0005] The head base 100 has a bearing 103 disposed on one side thereof, and a guide shaft 104 is inserted through the bearing 103. The guide shaft 104 is mounted on an optical recording / reproducing apparatus, and is mounted in parallel with a radial direction of an optical storage medium clamped by a clamp device (not shown). A yoke and a permanent magnet are arranged in parallel with the guide shaft 104, and constitute a magnetic circuit together with a coil of an optical head (not shown). This coil is arranged below the optical unit 102.

[0006] In the operation of the optical head, first, an electric current is passed in an arbitrary direction to a coil arranged below the optical unit 102. Then, the current value becomes the moving force for moving the head base 100 in the previous magnetic circuit, and the head base 100
Eventually, the objective lens 101 moves along the guide shaft 104. That is, the recording medium is moved by an arbitrary amount in a direction crossing the track.

This movement can be roughly divided into two cases.

First, the position of the head unit 102 is finely adjusted in order to irradiate one track so that the laser light does not deviate. In other words, this is generally called a tracking control operation, and a laser beam having a spot diameter of about 1.3 μm at the irradiation position is converted into a pit row having a width of 0.5 μm and a pit interval of 1.6 μm ± 0.1 μm. The objective lens 101 is minutely moved together with the optical unit 102 so that irradiation is performed with an accuracy of 1 μm. Specifically, 3
A track control signal is reproduced by a known method such as a beam method, a push-pull method, and an astigmatism method, and a coil disposed below the optical unit 102 is energized in an arbitrary direction by the tracking signal, thereby forming a magnetic circuit. A minute movement is performed by the action.

In the prior art, the head base 10
Although the movement of 0 is used for the tracking control operation, there is another type in which the tracking control operation is performed using an actuate in the optical unit 102. Generally, an actuator is configured on the premise of minute movement, and is used for focusing control operation and the like. Therefore, for example, a rotating shaft or a leaf spring is used, and the objective lens supported by the rotating shaft or the leaf spring is moved by a magnetic circuit. I will not explain the details here, but all methods along with fork
It is necessary to be configured to be biaxially drivable so that a tracking operation can be performed. Therefore, the configuration is more complicated than that of a single-axis configuration only for focusing, and the weight increases. Therefore it would hinder to realize the weight reduction is an object of the optical head.

Therefore, in the present invention and its prior art, an optical head on the premise of weight reduction is shown as a specific embodiment and a specific prior art.

In the second case, which is generally called a search operation, a laser beam crosses a plurality of tracks to record and reproduce a signal on a target track.

In order to search for a target track, it is necessary to move at a high speed and stop precisely at the target track position. As a specific operation for this, a coil arranged below the optical unit 102 is energized by an arbitrary search command, and the head base 100 is quickly moved in an arbitrary direction (radial direction of the recording medium) by the action of a magnetic circuit.
Go to Then, in the vicinity of the target track, power is supplied in the direction opposite to the power supply direction, and a moving force is applied in the direction opposite to the current direction to stop. At this time, naturally, a single reverse energization does not stop, but a plurality of forward and reverse energizations are required, and the reciprocation (a certain period of damped oscillation) is performed and the operation is stopped.

[0013]

As described in the section of the prior art, when stopping at a target search position (target tracking position) in a high-speed search or the like, it is not possible to stop immediately, and several times. Had stopped after reciprocating. This is caused by the law of dynamics called the law of inertia, and the higher the speed of movement, the longer the time until this stop, that is, the longer the search time.

Therefore, even if the weight of the optical head is reduced and the optical head can be moved at a high speed to shorten the moving time, it takes a long time to stop. Could not be searched. On the other hand,
No. 59-121660 “Brake device for magnetic disk drive”
The brake shoe attached to the magnet
Operates by being placed close to the drum and energized for a certain period
Brake shoe by the self-holding solenoid
Contact and separate the brake drum, and
The brake shoe is braked by the suction force of the gunnet.
Brake that is kept in contact with the brake system
A unit is disclosed. However, this one
Simply brake the brake shoe that is activated by electromagnetic force.
Brake against brake drum
Alternatively, it controls the release of braking and uses a self-holding
The self-maintaining state of operation even after the power supply is cut off
It was nothing more than an attempt to save power by using a computer.
In addition, the brake shoe is in contact with the outer circumference of the brake drum.
Stop the brake chute and brake drum.
Because the occupied space of the braking means, including
Have problems such as difficulty in downsizing
Was. In addition, Japanese Utility Model Application Laid-Open No.
Information reading means and drive coil section
When the drive current is supplied to the drive coil
When the drive current is not supplied,
Indirectly or directly engaging to control the movement of the rotating arm
A braking device configured to move is disclosed. This one
Has a magnet on the rotating arm.
Gnet only drives the rotating arm electromagnetically
To generate braking on the rotating arm
Not a thing. In addition, the rubber sheet that contacts the rotating arm
Unnecessary transfer by the information reading means
A pivoting arm rather than a braking means to prevent movement
Rotation restraint means to keep the movement of the
While applying a certain frictional load to the rotating arm during rotation.
Is not configured to allow rotation, so the driving force and braking
Raise the rotation accuracy of the rotation arm with a delicate balance of force
It is impossible to devise a device such as
The structure of the braking member that suppresses the rotation of the rotating arm
And requires a certain amount of occupied space.
With the problem that it is difficult to make the entire
Was something.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optical head which can quickly and accurately stop at a target track position during a high-speed search.

[0016]

According to a first aspect of the present invention , a guide extending in a radial direction of a recording medium is provided.
Shaft and a guide shaft slidably held on the guide shaft.
Head, and the recording medium supported by the head base.
An optical unit for irradiating the body with laser light, and the head
A moving hand for moving a base along the guide shaft
A step, and a guide shaft disposed on the head base.
A bearing through which the shaft is inserted, and the guide inside the bearing.
Guide shaft protruding in the radial direction of the
Outer periphery sealed always-on resilient manner abutting engagement of adversely sliding friction resistance
And a resilient arm.
You. A second device extends in the radial direction of the recording medium.
A guide shaft made of a magnetic material;
A head base slidably held and a head base
An optical unit that is supported and irradiates the recording medium with laser light.
Knit and the head base along the guide shaft.
Moving means for moving the head base;
A bearing portion through which the guide shaft is inserted,
Protruded inside the receiving part in the radial direction of the guide shaft
An arm, and a guide shaft provided at a tip end of the arm;
Magnetically attracts and locks to the outer periphery of the shaft to reduce sliding friction resistance
And a magnet that exerts
is there. Still further, a third device is the radial direction of the recording medium.
A guide shaft made of a magnetic material extending
A head base slidably held in a shaft, and the head
The recording medium is supported by a base and is irradiated with laser light.
An optical unit, and the head base
Moving means for moving along the shaft, and the head base
A bearing portion disposed above and through which the guide shaft is inserted
Inside the bearing portion in the radial direction of the guide shaft.
A protruding arm, and a power supply
When magnetized, the outer periphery of the guide shaft is magnetically absorbed.
And an electromagnet that exerts sliding frictional resistance when engaged and stopped.
It is characterized by the following.

[0017]

According to the present invention, it is possible to accurately stop at a target track position in a short time during a high-speed search of the optical head.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIGS. 1 (a) and 1 (b) and FIGS. FIG. 1 is a top view of the optical head of the present invention.

In the optical head shown in FIG. 1, an objective lens 1 for irradiating a laser beam emitted from a laser light source (not shown) onto a recording medium and an optical unit 2 having an actuator for slightly moving the objective lens in a focus direction. And a head base 10 on which is mounted.

The head base 10 has the bearing 3 disposed on its minus side, and the guide shaft 4 is inserted through the bearing 3. The guide shaft 4 is mounted on an optical recording / reproducing apparatus, and is mounted parallel to a radial direction of an optical storage medium clamped by a clamp device (not shown). A yoke and a permanent magnet are arranged in parallel to the guide shaft 4, and together with the coil 6, constitute a magnetic circuit (linear motor). This coil 6 is arranged below the optical unit 2.

A brake unit 5 is disposed adjacent to the bearing 3 so that the guide shaft 4 can be inserted therethrough. The brake unit 5 is provided with the head base 10
Which forms a frictional state between the shaft and the guide shaft 4, FIG.
As shown in the sectional view of FIG. 3 and FIG. 3, a mechanism for generating friction is provided.

[0022] Specifically, as shown in FIG. 2, when inserted through the guide shaft 4 in the bearing portion 15, the pressing Subeku springy arm 1 the guide shaft 4 from the circumferential
1 is extending.

In the embodiment shown in FIG. 3, a guide shaft (in this case, a magnetic shaft) 4a is inserted into a bearing portion 15, and at this time, an arm 12 extending in a radial direction of the shaft is provided.
A magnetic force is applied to the guide shaft 4a by the magnet 13 attached to the tip of the
0 and a guide shaft 4a form a frictional state. Incidentally, the magnet 13 and the guide shaft 4a are not in contact with each other.

The specific operation of the above configuration will be described.

First, in the tracking operation, a tracking control signal is reproduced from the reproduction signal, the coil 6 is energized by the control signal, and the head base 10 is slightly moved in an arbitrary direction. At this time, energy for movement is required as much as the amount of the brake unit 5 as compared with the prior art. However, since the movement is very small on the order of microns, no originally large energy was required. No energy is required.

During a search, the coil 6 is energized by an arbitrary search command, and the head base 10 moves at a high speed. At this time, at the start of movement, relatively large energy is required due to the action of static friction. However, during the search, dynamic friction is required. However, it is still more difficult to move than usual, so it is necessary to increase the applied energy and to move at high speed. Then, at the time of stopping, a current in the opposite direction to the current is applied to the coil 6, or if the friction of the brake unit 5 is large, the energization is simply stopped and the movement of the head base 10 is stopped. That is, when the head base 10 moves, a force is always applied in the direction opposite to the moving direction (due to frictional resistance) due to the frictional action of the brake unit 5, and the moving force is reduced depending on whether the direction of the applied current is reversed or stopped. If the stop or the direction is reversed, the movement is stopped in a shorter time than before. Therefore, the search time can be reduced.

In the above-described embodiment, the unit for each movement can be of any configuration. In particular, the unit for performing the tracking operation using an actuator may be used, and the configuration for the movement does not need to use a magnetic circuit. The point is that the present invention can be applied to all optical heads as long as they assist movement using a guide shaft.

In the embodiment shown in FIG. 3, an electromagnet may be used instead of the magnet 13. Then, since the electromagnet operates as a magnet at an arbitrary time, the brake can be selectively applied.
Specifically, the magnet action (brake operation) is turned off at the start of the search, when the vehicle is moving at a high speed in the search, or during the tracking control operation, and the magnet is turned off only when the search is stopped. It is possible to turn on the operation (braking operation). With this, when searching, when moving at high speed, and when performing tracking control operation, it can be realized with the same amount of energy as before, brake operation is performed only when stopping, and accurate short To stop.

[0029]

[Effects of the invention] As described above , the first invention
If the guide shuffs on the bearings
The guide shaft radially inside the bearing.
The spring arm protruding from the
It is configured to apply sliding friction resistance by elastically abutting and locking.
Therefore, the spring
The head generates constant sliding friction resistance at all times,
From the point when the driving force of the moving means to the
The inertia force acting on the head base loses the sliding friction resistance,
To reduce the time it takes for the base to shut down
Which enables you to search accurately and quickly
Track position and spring
To press the guide shaft radially outward,
It can be installed compactly in the annular bearing part.
Of braking means consisting of a bearing part and a springy arm
Is very compact,
Product value, especially for CD-ROM devices.
To search for desired data from a large amount of data
Excellent effects such as being suitable for In addition, the second consideration
According to the plan, the bearing part arranged on the head base is inserted
Guide shaft made of magnetic material, and inside the bearing
At the tip of the arm protruding in the radial direction of the guide shaft,
Gnet is installed and always magnetic around the outer circumference of the guide shaft.
A structure that exerts sliding frictional resistance by sucking and locking to the surface
Magnetically attracts and locks to a guide shaft made of magnetic material
Magnets always generate a constant sliding friction resistance.
With, the driving force of the moving means with respect to the head base was refused
From the moment, the inertial force acting on the head base is the sliding friction resistance
To reduce the time it takes for the headbase to stop
Which allows for accurate and short searches
You can find the target track position in time, optical recording
The commercial value of the playback device can be increased.
From a large amount of data such as a D-ROM device,
It has excellent effects such as being suitable for data search devices.
You. Further, according to the third invention, it is arranged on the head base.
Guide shaft made of magnetic material inserted through bearing
And protrude inside the bearing in the radial direction of the guide shaft.
An electromagnet at the end of the arm
Magnetically attracts and locks to the outer circumference of the guide shaft when magnetized
The sliding frictional resistance so that
Electromagnet that magnetically attracts and locks the guide shaft
Generates constant sliding friction resistance only when energized
Moving means relative to the head base
By energizing and exciting the electromagnet when the driving force of
Inertial force acting on the head base loses sliding friction resistance
Reduce the time it takes for the headbase to stop
This allows you to search accurately and quickly during a search.
Optical recording and reproducing device
Product value, especially CD-RO
Search for target data from a large amount of data
It has excellent effects such as being suitable for a searching device.

[Brief description of the drawings]

1A and 1B are optical heads of the present invention, respectively.
-Top view and side view showing the embodiment.

FIG. 2 is a sectional view of the brake unit according to the embodiment of the present invention, which is shown as a sectional view taken along line XX of FIG. 1 (a).

FIG. 3 is a sectional view of another embodiment of the brake unit of the present invention, which is shown as a sectional view taken along line XX of FIG. 1 (a).

FIG. 4 is a top view showing an example of a conventional optical head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Objective lens 2 Optical unit 3 Bearing 4 Guide shaft 4a Magnetic shaft 5 Brake unit 6 Moving means (coil) 10 Head base 11 Springy arm 12 Arm 13 Magnet 15 Bearing part

Claims (3)

(57) [Scope of request for utility model registration] 1. A guide shaft extending in a radial direction of a recording medium.
And a head slidably held on the guide shaft
A base, supported by the head base,
An optical unit for irradiating a laser beam;
Moving means for moving the tool along the guide shaft
And the guide shuff disposed on the head base.
A bearing portion through which the guide is inserted, and the guide inside the bearing portion.
The guide shaft protrudes in the radial direction of the shaft.
Constantly and elastically abuts the outer circumference to exert sliding friction resistance
An optical head comprising: a springy arm . 2. A magnetic material extending in a radial direction of a recording medium.
Guide shaft and slidable on the guide shaft
A held head base, supported by the head base,
An optical unit that irradiates the recording medium with laser light,
The head base is moved along the guide shaft.
Moving means for disposing, and disposed on the head base,
A bearing portion through which the guide shaft is inserted, and inside the bearing portion
An arm protruding in the radial direction of the guide shaft,
An outer periphery of the guide shaft, which is disposed at a tip of the arm;
Magnetically attracts and locks the magnet to the sliding frictional resistance
An optical head comprising a net . 3. A magnetic material extending in a radial direction of a recording medium.
Guide shaft and slidable on the guide shaft
A held head base, supported by the head base,
An optical unit that irradiates the recording medium with laser light,
The head base is moved along the guide shaft.
Moving means for disposing, and disposed on the head base,
A bearing portion through which the guide shaft is inserted, and inside the bearing portion
An arm protruding in the radial direction of the guide shaft,
It is arranged at the tip of the arm, and when energized and excited,
Sliding friction by magnetically attracting and locking to the outer circumference of the guide shaft
An optical head , comprising: an electromagnet that exerts resistance .