JP2002208173A - Optical head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the securing of a high data transfer rate compatible with the reducing of the size and weight of an optical disk recording/reproducing device, and also to make a steady recording/reproducing operation possible. SOLUTION: On one optical bench 11, there are mounted a plurality of objective lenses 31a, 31b, actuators 40a, 40b, and optical system units 20a, 20b. For one side of a disk 50 for which DVD-RAM of a zone CLV system is employed, the objective lenses 31a, 31b on the optical bench 11 are arranged with roughly half a distance apart of the width in the zone radial direction so that no heat of laser spots is transferred to each other; using the laser beam condensed by these objective lenses 31a, 31b, recording and reproduction are carried out simultaneously, thereby making the securing of a high data transfer rate and the reducing of the size and weight compatible in an optical disk recording/ reproducing device.

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 for an information recording / reproducing apparatus for an optical disk recording medium.

[0002]

2. Description of the Related Art In recent years, optical disk recording / reproducing apparatuses have been used for recording / reproducing moving images. However, it has been necessary to increase the transfer rate of recording / reproducing data in order to cope with higher-quality recording. As a means of doing this, the IEICE Tech.
-37 (1994-10).

Here, an optical system required for recording and reproduction and an actuator for condensing a laser are each mounted on one optical bench, and four optical benches are arranged on both sides of a disk. By irradiating a single disk with a total of eight lasers at the same time to perform recording and reproduction, a data transfer rate eight times that of a single laser alone can be secured, and high-quality video recording and reproduction can be performed. I have.

As in the first conventional example, a configuration in which a plurality of optical systems and actuators are mounted on one optical bench to simultaneously record data on a disk with a plurality of lasers is conceivable. Patent WO97 / 42632
Exists as Hereinafter, the configuration of the second conventional example will be described.

The optical table has an optical system unit for DVD and C
The optical system unit for D is incorporated, and the DVD objective lens and the CD objective lens are arranged close to each other. Here, the optical system unit for DVD and the optical system unit for CD include:
Each is equipped with a semiconductor laser and an objective lens having a wavelength optimal for reading data from a DVD disk and a CD disk. The optical table is guided by a group of guide rails so that the DVD objective lens and the CD objective lens can be moved substantially in the radial direction of the optical disk fixed to the spindle motor.

Next, an outline of the reproducing operation in the second conventional example will be described. When a disk is mounted on the optical disk recording / reproducing apparatus, the type of the optical disk is determined at an initial stage of the start-up operation. For example, when the optical disk is a DVD video disk, only the DVD optical system unit continues the start-up operation and reads information on the disk necessary for start-up. When a reproduction command is received after the start-up is completed, the laser is focused on the DVD video disk by controlling the DVD objective lens, the track is traced, and the moving image data is continuously read. During this reproducing operation, the optical system unit for CD is kept in a non-operating state.

[0007]

However, in the first conventional optical disk recording / reproducing apparatus, the mounting of a plurality of optical benches complicates the structure mechanically, increases the weight and increases the weight due to the arrangement of the guide rails. Since the occupied space becomes large, it is difficult to reduce the size of the device, which is not suitable for mounting on a portable device such as a video camera.

A second conventional optical disk reproducing apparatus is a DVD or CD optical disk incorporated in one optical bench.
Only one of the optical system units functions to reproduce data on the disc. Therefore, when two optical systems are simultaneously operated on one side of an optical disk to perform recording and reproduction for the purpose of increasing the data transfer speed, laser irradiation is performed on a close position on the disk to generate heat when forming one recording mark. In this case, there is a problem of thermal interference that deteriorates the shape quality of the other recording mark, and two actuators for driving the objective lens, which are operated independently, are arranged close to each other, so that the driving magnetic field of one actuator affects the other driving magnetic field. The problem of interference causes a problem of optical interference in which stray light of two lasers is mixed as noise in one optical bench.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and enables both the securing of a high data transfer rate of an optical disk recording / reproducing apparatus and the reduction in size and weight of equipment, and the deterioration of the shape of recording marks on a disk and the objective of the invention. It is an object of the present invention to provide an optical head capable of realizing a stable recording / reproducing operation by suppressing lens control instability, noise mixing in a recording / reproducing data signal, and the like.

[0010]

According to another aspect of the present invention, there is provided an optical head comprising: a plurality of lens holders for individually holding a plurality of objective lenses; A plurality of actuators that support the lens holder and drive each independently, and have a laser light receiving / emitting unit, and guide the irradiated laser light to the objective lens to condense it on a disk and transfer data to the disk. A plurality of optical system units for performing recording and reproduction, and the plurality of actuators and the plurality of optical system units are fixedly supported so that the plurality of objective lenses are arranged close to each other, and the plurality of objective lenses are mounted on the disk. An optical table that guides and supports the inner and outer peripheral portions so as to be able to move freely in a substantially radial direction between the inner and outer peripheral portions; Wherein the plurality of actuators and the plurality of optical system units are fixedly supported on the optical table so that the plurality of objective lenses are arranged at a predetermined distance offset in a substantially radial direction of the disk. It is.

According to the configuration of the first aspect, a plurality of optical system units, an objective lens, and an actuator are mounted on one optical bench to ensure both a high data transfer rate of the optical disk recording and reproducing apparatus and a reduction in size and weight of the apparatus. Possible,
In addition, by keeping the irradiation position of the laser beam at a distance in the radial direction of the disc, it is possible to suppress the deterioration of the recording mark shape quality by another optical system unit due to the heat at the time of forming the recording mark by one optical system unit, and to achieve a stable operation. An optical head capable of performing a recording / reproducing operation can be realized.

An optical head according to a second aspect of the present invention comprises:
2. The configuration according to claim 1, wherein the data area of the disk is divided into a plurality of concentric zones, the zone widths of the zones in the radial direction are substantially equal, and the zones are adjacent in the plurality of objective lenses. The offset distance in the radial direction of the two disks is set to a length obtained by dividing the zone width by the number of the objective lenses.

According to the configuration of the second aspect, when the disk is of the zone CLV type, within one zone where the disk rotation speed is constant, for example, from the start point of the zone to the intermediate point, the first optical system unit and the zone The second optical system unit continuously records and reproduces data from the intermediate point to the end point. In each zone, the tracking operation of the optical head is performed only for movement to an adjacent track, and a large track is obtained only for movement between zones. No jump occurs. Therefore, an optical head that can maintain a basically stable tracking state during recording and reproduction can be realized.

According to a third aspect of the present invention, in the optical head according to the first or second aspect, the disc is recorded or reproduced on an inner circumference or an outer circumference from a data area so that the optical system is tested. A disk learning area for learning the laser power or the like of the unit has a substantially concentric shape, and among the two optical system units that continuously perform the learning operation among the plurality of optical system units, the optical system unit that precedes the optical system unit The disk radial direction control of the actuators corresponding to the two objective lenses such that the objective lens corresponding to the other optical system unit is in a standby state at the head of the disk learning area during the learning operation of the system unit. And drive control of the optical bench.

According to the third aspect of the present invention, when the optical head performs the learning operation in the disk learning area at the time of startup, the learning operation of the next optical system unit is performed immediately after the preceding optical system unit completes the learning operation. It is possible to start, and it is not necessary to move the optical bench every time the optical system unit is switched to perform tracking of the next objective lens, thereby realizing an optical head capable of completing the learning operation in a shorter time.

Further, in the optical head according to the present invention, there are provided a plurality of lens holders for individually holding a plurality of objective lenses, and a plurality of actuators for supporting the plurality of lens holders and independently driving the respective lens holders. When,
A plurality of optical system units having a laser light emitting / receiving unit and guiding the irradiated laser light to the objective lens, and condensing the data on a disk to record and reproduce data on the disk; The plurality of actuators and the plurality of optical system units are fixedly supported so as to be disposed in such a manner that the plurality of objective lenses can freely move in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk. An optical table for guiding and supporting the disk, and each of the plurality of objective lenses focuses a laser beam on a different one of the plurality of recording layers to record data on the disk having a plurality of recording layers in a thickness direction. The actuator is controlled to perform reproduction.

According to the configuration of the fourth aspect, a plurality of optical system units, an objective lens and an actuator are mounted on one optical bench to ensure a high data transfer rate of the optical disk recording / reproducing apparatus and at the same time reduce the size and weight of the apparatus. Make it possible. Further, even when a plurality of objective lenses are arranged close to each other and the position of the laser spot is close on the disk surface, the recording layer on which the laser light irradiated by each optical system unit is focused is separated in the thickness direction of the disk. Therefore, it is possible to realize an optical head in which heat generated by a laser spot at the time of forming a recording mark is prevented from propagating on the recording layer, thereby deteriorating the shape quality of the recording mark due to another laser spot.

The optical head according to claim 5 of the present invention has a plurality of lens holders for individually holding a plurality of objective lenses, and a plurality of actuators for supporting the plurality of lens holders and independently driving each of the plurality of lens holders. When,
A plurality of optical system units having a laser light emitting / receiving unit and guiding the irradiated laser light to the objective lens, and condensing the data on a disk to record and reproduce data on the disk; The plurality of actuators and the plurality of optical system units are fixedly supported so as to be disposed in such a manner that the plurality of objective lenses can freely move in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk. An optical table for guiding and supporting, and for the disc capable of recording data on both the land and the groove of the recording layer, at least a pair of the objective lenses are dedicated to the adjacent land and the groove, respectively. And controlling the actuator so that the laser is focused to record and reproduce data.

According to the fifth aspect of the present invention, a plurality of optical system units, an objective lens, and an actuator are mounted on a single optical bench to ensure a high data transfer rate of an optical disk recording / reproducing apparatus and at the same time reduce the size and weight of the apparatus. Make it possible. Further, the laser light collected by the pair of objective lenses is
One is only the land part of the substantially spiral track on the disk,
On the other hand, since data recording and reproduction are performed by continuously tracing only the groove portion, basically no track jump occurs, or stable track jump only occurs from the adjacent land portion to the land portion and from the groove portion to the groove portion. By the tracking operation, it is possible to realize an optical head capable of recording and reproducing the entire surface of the disk.

An optical head according to a sixth aspect of the present invention comprises:
A plurality of lens holders for individually holding a plurality of objective lenses, a plurality of actuators for supporting the plurality of lens holders and independently driving each of the plurality of lens holders, and a laser light receiving and emitting unit for laser light and irradiating laser light. A plurality of optical system units that guide the objective lens to condense light on a disc and record and reproduce data on the disc, the plurality of actuators and the plurality of An optical table that fixedly supports an optical system unit and guides and supports the plurality of objective lenses so as to be able to freely move in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk; And a magnetic shield means for intercepting the magnetic field generated by the actuator.

According to the structure of the sixth aspect, a plurality of optical system units, an objective lens and an actuator are mounted on one optical bench to ensure both a high data transfer rate of an optical disk recording / reproducing apparatus and a reduction in size and weight of the apparatus. Make it possible. Further, it is possible to realize an optical head that can suppress the magnetic fields of a plurality of actuators that operate independently and simultaneously from affecting adjacent actuators, and maintain stable tracking and focusing operations.

According to a seventh aspect of the present invention, in the optical head according to the sixth aspect, the magnetic shield means is arranged at a position substantially symmetric with respect to the center of the objective lens. Things.

According to the configuration of the seventh aspect, the influence of the magnetic shield means on the actuator magnetic field is made symmetric so as to be easily balanced, and the control of the tracking and focusing operations can be further stabilized.

The optical head according to claim 8, further comprising: a plurality of lens holders for individually holding a plurality of objective lenses; and a plurality of actuators for supporting the plurality of lens holders and independently driving each of the plurality of lens holders. When,
A plurality of optical system units having a laser light emitting / receiving unit and guiding the irradiated laser light to the objective lens, and condensing the data on a disk to record and reproduce data on the disk; The plurality of actuators and the plurality of optical system units are fixedly supported so as to be disposed in such a manner that the plurality of objective lenses can freely move in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk. And an optical table for guiding and supporting, and a light blocking means for blocking laser light is arranged between the plurality of lens holders.

According to the configuration of the eighth aspect, a plurality of optical system units, objective lenses and actuators are mounted on one optical bench to ensure both a high data transfer rate of the optical disk recording and reproducing apparatus and a reduction in size and weight of the apparatus. Make it possible. Further, it is possible to prevent the stray light of the laser of each optical system unit from jumping into another optical system unit as noise in the optical bench, thereby realizing an optical head that performs a stable recording / reproducing operation.

Further, in the optical head according to the ninth aspect of the present invention, in the configuration according to the eighth aspect, the height of the light shielding means is built in the plurality of optical system units from the bottom of the optical bench. The laser light is secured to a height above a position of a rising mirror for guiding a laser beam perpendicularly to the disk surface.

According to the configuration of claim 9, the stray light of the laser of each optical system unit can be prevented from jumping into another optical system unit as noise by the light shielding means provided between each optical system unit.

An optical head according to a tenth aspect of the present invention is the optical head according to the eighth aspect, wherein the light shielding means is made of a magnetic material.
According to the configuration of the tenth aspect, it is possible to suppress the magnetic fields of the plurality of actuators that operate independently and simultaneously from affecting the adjacent actuators, and the stray light of the laser of each optical unit jumps into another optical unit as noise. This can be prevented by a single member, and both stable recording / reproducing operation and reduction in size and weight of the optical head can be achieved.

The optical head according to claim 11, wherein the plurality of lens holders individually hold a plurality of objective lenses, and the plurality of actuators supporting the plurality of lens holders and independently driving each of the plurality of lens holders. When,
A plurality of optical system units having a laser light emitting / receiving unit and guiding the irradiated laser light to the objective lens, and condensing the data on a disk to record and reproduce data on the disk; The plurality of actuators and the plurality of optical system units are fixedly supported so as to be disposed in such a manner that the plurality of objective lenses can freely move in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk. An optical bench for guiding and supporting, wherein the plurality of optical system units are fixedly supported at different heights on the optical bench.

According to the configuration of the eleventh aspect, a plurality of optical system units, an objective lens, and an actuator are mounted on a single optical bench to ensure both a high data transfer rate of an optical disk recording / reproducing apparatus and a reduction in size and weight of the apparatus. Make it possible. Furthermore, by changing the mounting height of the optical system unit, the stray light between the optical system units is suppressed from entering each other as noise in the range below the rising mirror that irradiates the disk with laser light as parallel light, and it is stable. An optical head that performs a recorded / reproduced operation can be realized.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 of the present invention will be described below with reference to FIGS. First, the configuration will be described with reference to FIG. In the first embodiment, although the recording and reproducing system using the first and second laser beams arranged approximately symmetrically is provided, the basic configuration is the same. The second recording and reproducing system is denoted by the letter b, and the description is omitted.

On the optical table 11 of the optical head 1, a first optical system unit 20a is mounted. The first optical system unit 20a includes a first semiconductor laser module 21a which is a laser light receiving / emitting unit, a first reflecting prism 22a that bends the path of the laser light, and a first semiconductor laser module that shapes the diffused light into parallel light. And a first raising mirror 24a for guiding the laser beam perpendicular to the disk surface. Above the first raising mirror 24a, a first objective lens 31a for condensing a laser beam on a disk surface is arranged.
a is fixed to the first lens holder 32a.

Further, the first lens holder 32a is
The first actuator 40a is fixed to the optical bench 11 by the first actuator 40a.
, A magnet part (not shown) fixed to the first lens holder 32a, and a coil part 41a having one end fixed to the first lens holder 32a and the other end fixed to the optical bench 11.
And the first suspension wire 42a. As a result, the first objective lens 31a
Fine adjustment of the position can be performed in the direction perpendicular to the surface of the disk 50 and in the radial direction of the disk 50.

Here, the disk 50 corresponds to the zone CLV system employed in DVD-RAMs and the like. As shown in FIG. 3, a recordable data area 51 on the disk 50 is a concentric zone. Each zone width X is set to be substantially equal to the offset distance. A disk learning area 52 is further provided in the inner peripheral portion of the data area 51.
Is provided to secure an area where recording and reproduction of temporary data can be tried for a learning operation such as optimizing the laser power when the drive is started.

The first objective lens 31a and the second objective lens 31b are arranged at an equal distance from the center line of the disk 50 and divide the zone width X of the disk 50 into two in the radial direction of the disk 50. Distance, ie X / 2
It is attached to the optical bench 11 so as to be offset only to the outer peripheral side.

Thus, the first objective lens 31a and the second
Since the laser spot position by the objective lens 31b is spaced a sufficient distance in the radial direction of the disk 50, the heat generated by the focusing of the laser beam by the first objective lens 31a is generated by the second objective lens 31b. This prevents the shape quality of the recording mark from deteriorating by propagating to the light collecting portion.

A light shielding plate 12, which is an example of a light shielding means and a magnetic shielding means, is disposed between the first optical system unit 20a and the second optical system unit 20b. That is, the light shielding plate 12 is made of a magnetic material and also functions as a magnetic shielding means.
The height exceeding 1b is secured. Further, the light shielding plate 12
As a member having the same material and shape as
Magnetic shields (an example of magnetic shield means) 13a and 13b at positions substantially symmetric with respect to the center lines of
b is arranged.

In this configuration, the light shielding plate 12 prevents stray light generated in the first optical system unit 20a and the second optical system unit 20b from entering the other as noise. The generation of stray light is a problem when the optical axis is running parallel to the bottom surface of the optical bench 11, particularly before the laser light is shaped into parallel light by the collimator lenses 23a and 23b. Mirror 2
After being guided perpendicularly to the bottom surface of the optical bench 11 at 4a and 24b, there is very little possibility that the laser beams will interfere with each other. Therefore, it is sufficient that the light shielding plate 12 should be provided up to the height of the rising mirrors 24a and 24b.

However, here, the light shielding plate 12 is made of a magnetic material, and is used as a magnetic shield means for suppressing magnetic interference between the actuators 40a and 40b arranged close to each other. Further, by adding the dummy magnetic shields 13a and 13b as a set with the light shielding plate 12, the influence of the light shielding plate 12 and the dummy magnetic shields 13a and 13b as the magnetic shielding means on the actuator magnetic field is made symmetrical so as to be easily balanced. The control of the focusing and tracking operations can be further stabilized.

In the first embodiment, an example is described in which the light shielding plate 12 is used to prevent two types of laser beams from interfering with each other. However, as another method, the second optical system unit is mounted on the optical bench 11. It is also conceivable that the height of the mounting surface of 20b is lower than the height of the mounting surface of the first optical system unit 20a. Also in this method, since the optical axis height in the first optical system unit 20a and the optical axis height in the second optical system unit 20b are not coplanar, optical mutual interference can be prevented. it can. However, due to this, it is necessary to extend the optical path length above the rising mirrors 24a and 24b in design, but it is not necessary to make a large design change of the optical system in this region because the laser is parallel light.

Next, referring to FIG. 2, a schematic configuration of a drive on which the head having the above configuration is mounted will be described. A spindle motor 6 is mounted on the drive base 5, and a disk 50 is fixed to the spindle motor 6. The optical head 1 is guided by guide shafts 7 and 8 and is driven by a stepper 9 to be movable in the radial direction of the disk 50.

The operation of the optical head 1 for recording data on the disk 50 in the first embodiment will be described below. First, when the drive is started, the optical head 1 is moved to the first actuator 40a and the second actuator 40b.
Are operated to pull in the focusing servo and the tracking servo, respectively. After the servo pull-in is completed, first, the first objective lens 31a
The optical bench 11 is moved to a position where the first optical system unit 20a can be accessed, and the learning operation of the first optical system unit 20a is executed in the state of FIG.

During this time, the optical table 11 and the actuators 40a and 40b are controlled so that the second objective lens 31b enters a standby state at the head of the disk learning area 52, and the learning operation of the first optical system unit 20a is performed. Immediately after the completion, the learning operation of the second optical system unit 20b is started.

After the learning operation is completed, the first objective lens 31a
Moves to the start address of the first zone 51-1 at the innermost periphery of the data area 51 of the disk 50 and waits. At the same time, the second objective lens 31b, which is offset from the first objective lens 31a by X / 2, which is obtained by dividing the zone width X into two parts, in the radial outer side of the disk 50, is located at the center of the first zone 51-1. It moves to the address and enters the standby state.

When a recording start command is received, the first objective lens 31a and the second objective lens 31b simultaneously record addresses sequentially from the head address and the intermediate address of the first zone 51-1. I do. When the first objective lens 31a and the second objective lens 31b reach the intermediate address and the final address, respectively, and the recording in the first zone 51-1 is completed, the first objective lens 31a is moved to the approximate distance X /. Then, the second objective lens 31b moves to the intermediate address of the second zone 51-2. This operation is repeated, and the disk 5
0 is recorded on the entire surface.

As described above, the optical head 1 according to the first embodiment
In this case, simultaneous recording is always performed by the two laser systems of the first optical system unit 20a and the second optical system unit 20b, so that a data transfer speed twice as high as that of the conventional optical head of one optical system unit can be secured. . In addition, during a recording operation, only a track jump to an adjacent track occurs other than a seek operation at a distance of half a zone width X / 2 when crossing a zone, so that there are few factors that cause unstable tracking.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. First, the configuration will be described with reference to FIG. The basic structure of the optical head 1 is the same as that of the first embodiment, and the first objective lens 31a and the second objective lens 31
The only difference is that b is not offset in the radial direction of the disk 50. Therefore, a detailed description of the configuration is omitted.

However, the disc 50 used here is generally called a two-layer disc, and has two recording layers provided at different positions in the thickness direction on one side. Also, it corresponds to the zone CLV method adopted in DVD-RAM and the like, and has a recording layer A and a recording layer B.
For recording operations such as optimizing the laser power at the time of starting the drive in the recordable data areas 51A and 51B divided into concentric zones, and further inside the data areas 51A and 51B. Disk learning areas 52A and 52A in which recording and reproduction of temporary data can be tried.
2B are provided.

The operation of recording data on the disk 50 by the optical head 1 according to the second embodiment will be described below. First, when the drive is started, the optical head 1 operates the first actuator 40a and the second actuator 40b to perform focusing servo and tracking servo respectively. Here, in the present configuration, the first
The optical system unit 20a is dedicated to the recording layer A, and the second optical system unit 20b is dedicated to the recording layer B.
As shown in (1), the laser passing through the first objective lens 31a is focused on the recording layer A, and the laser passing through the second objective lens 31b is focused on the recording layer B.

After the servo pull-in is completed, the optical table 11 is first moved to a position where the first objective lens 31a can access the disk learning area 52A, and the learning operation of the first optical system unit 20a is executed in the state of FIG. I do. At the same time, the second objective lens 31b is also moved to the disc learning area 52B to execute the learning operation of the second optical system unit 20a. Since the disk learning areas 52A and 52B are present in portions having substantially the same diameter in the disk radial direction and the positions of the first objective lens 31a and the second objective lens 31b are not offset, the objective lenses 31a and 31b can be used without any problem. It is possible to simultaneously move to the disc learning area 52A or 52B.

After the learning operation is completed, the first objective lens 31a
Moves to the start address of the first zone 51-1A on the innermost circumference of the data area 51A of the recording layer A and waits. At the same time, the second objective lens 31b is also connected to the data area 5 of the recording layer B.
It moves to the first zone 51-1B on the innermost circumference of 1B and enters a standby state.

When a recording start command is received, the first objective lens 31a and the second objective lens 31b simultaneously receive the head address of the first zone 51-1A on the recording layer A and the first address on the recording layer B, respectively. Data is recorded by sequentially following the address from the head address of the zone 51-1B. At the time of this recording, both the first objective lens 31a and the second objective lens 31b perform a track jump to an adjacent track only for each round of the disk 50, and
Executes data recording on the entire surface of.

As described above, the optical head 1 according to the second embodiment
In this case, the first optical system unit 20a always has the recording layer A
In addition, since the second optical system unit 20b performs simultaneous recording on the recording layer B, a data transfer speed twice as high as that of the conventional optical head of one optical system unit can be secured. Also, during a recording operation, basically, only a track jump to an adjacent track does not occur, and a medium-long distance track jump does not occur, so that stable tracking can be realized.

Further, two spots on the substantially same radius
Although laser spots are formed at the spots, since a layer having a composition for preventing mutual thermal interference is formed between the recording layers focused on each other, the laser beam is condensed by the first objective lens 31a. The heat generated by the second objective lens 3
There is no possibility that the quality of the shape of the recording mark is deteriorated by propagating to the light condensing part by 1b.

Hereinafter, a third embodiment of the present invention will be described with reference to FIG. 4, FIG. 5, and FIG. First, the configuration will be described with reference to FIG. The basic configuration of the optical head 1 is the first embodiment.
And the same as in the second embodiment, the first objective lens 31a
The only difference is that the second objective lens 31b and the second objective lens 31b are not offset in the radial direction of the disk 50. Therefore, a detailed description of the configuration is omitted.

However, the disk 50 used here corresponds to land-groove recording in which recording is performed on both the land portion and the groove portion formed on the recording layer. In addition, it corresponds to the zone CLV system adopted in DVD-RAMs and the like, and has a recordable data area 51 divided into concentric zones, and a laser power of There is provided a disk learning area 52 in which recording and reproduction of temporary data can be tried for a learning operation such as optimization.

The operation of recording data on the disk 50 by the optical head 1 according to the third embodiment will be described below. First, when the drive is started, the optical head 1 operates the first actuator 40a and the second actuator 40b to perform focusing servo and tracking servo respectively.

In this configuration, the first optical system unit 20a functions only for the land portion 55 and the second optical system unit 20b functions only for the groove portion 56.
As shown in (1), the laser beam passing through the first objective lens 31a is focused on the land portion 55, and the laser beam passing through the second objective lens 31b is focused on the groove portion 56.

After the servo pull-in is completed, the optical table 11 is first moved to a position where the first objective lens 31a can access the disk learning area 52, and the learning operation of the first optical system unit 20a is executed in the state shown in FIG. I do. During this time the second
Of the optical table 11 and the actuator 40a so that the objective lens 31b is in a standby state at the head of the disc learning area 52.
And 40b are controlled, the first optical system unit 2
0a immediately after the completion of the learning operation of the second optical system unit 20a.
The learning operation of b is started.

After the learning operation is completed, the first objective lens 31a
Is the first zone 51-at the innermost circumference of the data area 51.
1 and moves to the start address of the first track of the land portion 55 and waits. At the same time, the second objective lens 31b also
It moves to the first track of the groove section 56 in the first zone 51-1 on the innermost periphery of the data area 51 and enters a standby state.

When a recording start command is received, the first objective lens 31a and the second objective lens 31b are simultaneously moved to the first address of the first track of the land 55 in the first zone 51-1 and the first zone, respectively. The address is sequentially traced from the first address of the first track of the groove section 56 in 51-1.
Data is recorded while performing a track jump from the land portion 55 to the land portion 55 or from the groove portion 56 to the groove portion 56 for each circumference. At the time of this recording, both the first objective lens 31a and the second objective lens 31b execute data recording on the entire surface of the disk 50 only by track jumping at every other track for each round of the disk 50.

As described above, the optical head 1 according to the third embodiment
Then, the first optical system unit 32a is always connected to the land 5
5. Since the second optical system unit 32b performs simultaneous recording in the groove portion 56, a data transfer speed twice as high as that of the conventional optical head of one optical system unit can be secured. During a recording operation, basically, only track jumps every other track from the land portion 55 to the land portion 55 or from the groove portion 56 to the groove portion 56 are performed, and a medium-long distance track jump does not occur. Can be realized.

Further, two points on the substantially same radius of the disk 50 are
Although the laser spots are formed at the spots, the land portions 55 and the groove portions 56, each of which focuses, are formed at such a level that the difference in height can prevent thermal interference. The heat generated by the condensing of the laser beam does not propagate to the converging portion formed by the second objective lens 31b, and the shape quality of the recording mark does not deteriorate.

As is clear from the above description, according to the embodiment of the present invention, two systems of lasers arranged on one optical bench 11 simultaneously record data on one surface of the disk 50. Although the configuration is easy, a high data transfer rate can be secured. Also, close to the objective lens 3
Even in the case where the configuration in which the laser spots 1a and 31b are arranged is adopted, the laser spot condensed by them is physically separated so that heat during recording does not propagate to each other.
The light shielding plate 12 as a magnetic shielding means is disposed between the optical system units 20a and 20b, and the light shielding plate 12 is disposed between the optical system units 20a and 20b. A stable recording / reproducing operation can be performed while suppressing the control instability of 31b, noise mixing in the recording / reproducing data signal, and the like.

[0065]

As described above, according to the optical head of the present invention, a plurality of objective lenses, actuators, and optical units are mounted on one optical bench, and a plurality of laser beams are simultaneously recorded on one surface of a disk. By performing the reproduction, it is possible to ensure both a high data transfer rate of the optical disk recording / reproducing apparatus and a reduction in size and weight of the device. Furthermore, even when the configuration in which the objective lenses are arranged close to each other, the laser spot from each objective lens is physically separated so that heat during recording does not propagate to each other, and a magnetic shield means is provided between each actuator. Stable configuration by arranging the light shielding means between each optical system unit, suppressing deterioration of the recording mark shape on the disk, instability of the control of the objective lens, noise mixing in the recording / reproduction data signal, etc. An optical head capable of performing a recorded / reproduced operation is realized.

[Brief description of the drawings]

FIG. 1 shows an optical head according to Embodiment 1 of the present invention,
(A) is a plan view, (b) is a longitudinal front view.

FIG. 2 is a plan view of a disk drive on which the optical head according to the first embodiment of the present invention is mounted.

FIG. 3 is a side view of the disk according to the first embodiment of the present invention.

FIG. 4 shows an optical head according to Embodiment 2 of the present invention,
(A) is a plan view, (b) is a longitudinal front view.

FIG. 5 is a plan view of a disk drive on which an optical head according to Embodiment 2 of the present invention is mounted.

FIG. 6 is a front view of a main part showing the concept of writing to a disk by the optical head according to the second embodiment of the present invention

FIG. 7 is a side view of a main part showing the concept of writing to a disk by an optical head according to Embodiment 3 of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical head 6 Spindle motor 11 Optical table 12 Light shield plate (Light shield means and magnetic shield means) 13a Dummy magnetic shield (Magnetic shield means) 13b Dummy magnetic shield (Magnetic shield means) 20a First optical system unit 20b Second optics System unit 21a First semiconductor laser module (light emitting / receiving unit) 21b Second semiconductor laser module (light emitting / receiving unit) 22a First reflecting prism 22b Second reflecting prism 23a First collimator lens 23b Second collimator lens 24a First rising mirror 24b Second rising mirror 31a First objective lens 31b Second objective lens 32a First lens holder 32b Second lens holder 40a First actuator 40b Second actuator 50 Disk 51 Over data area 51A the data area 51B data area 52 Disk learning area 52A disk learning area 52B disk learning area 55 land part 56 groove portion A recording layer B recording layer X zone width

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshiaki Nakamatsu 1006 Kazuma Kadoma, Kadoma-shi, Osaka Matsushita Electric Industrial Co., Ltd. F-term (reference) 5D119 AA01 AA10 AA24 BA01 BB13 BB20 EC44 FA02 FA08 LB12

Claims (11)

[Claims] A plurality of lens holders for individually holding a plurality of objective lenses; a plurality of actuators for supporting the plurality of lens holders and independently driving the plurality of lens holders; A plurality of optical system units for guiding the irradiated laser light to the objective lens and condensing the data on a disc to record and reproduce data on the disc, and the plurality of optical units so that the plurality of objective lenses are disposed in close proximity to each other. An optical table fixedly supporting the actuator and the plurality of optical system units and guiding and supporting the plurality of objective lenses so as to be freely movable in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk; When the plurality of actuators are not driven, the plurality of objective lenses are arranged to be offset by a fixed distance in a substantially radial direction of the disk. As the optical head, characterized in that said plurality of actuators and the plurality of the optical system unit is fixed supported on the optical bench. 2. The disk according to claim 1, wherein a data area is divided into a plurality of concentric zones, the zone widths of the zones in the radial direction are substantially equal, and two adjacent disk radii of the plurality of objective lenses are provided. The optical head according to claim 1, wherein the offset distance in the direction is set to a length obtained by dividing the zone width by the number of the plurality of objective lenses. 3. The disk has a disk learning area for learning the laser power or the like of the optical system unit by performing recording and reproduction on an inner circumference or an outer circumference from a data area in a substantially concentric shape. Of the two optical system units that continuously perform the learning operation among the plurality of optical system units, the objective lens corresponding to the other optical system unit during the learning operation of the preceding optical system unit is the disk learning unit. 3. The optical disc drive according to claim 1, wherein the disk radial direction control of the actuators corresponding to the two objective lenses and the drive control of the optical bench are performed so that the optical disk enters a standby state at a head of an area. 4. Light head. And a plurality of lens holders for individually holding the plurality of objective lenses, a plurality of actuators for supporting the plurality of lens holders and independently driving the plurality of lens holders, and a laser light receiving / emitting unit. A plurality of optical system units for guiding the irradiated laser light to the objective lens and condensing the data on a disk to record and reproduce data on the disk, and the plurality of optical units so that the plurality of objective lenses are disposed in close proximity to each other. An optical table that fixedly supports the actuator and the plurality of optical system units and guides and supports the plurality of objective lenses so that the plurality of objective lenses can freely move in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk. For the disc having a plurality of recording layers in the thickness direction, each of the plurality of objective lenses focuses a laser beam on a different one of the plurality of recording layers to perform demultiplexing. Optical head and controlling said actuator to perform recording and reproduction of data. 5. A semiconductor device comprising: a plurality of lens holders for individually holding a plurality of objective lenses; a plurality of actuators for supporting the plurality of lens holders and independently driving each of the plurality of lens holders; A plurality of optical system units for guiding the irradiated laser light to the objective lens and condensing the data on a disc to record and reproduce data on the disc, and the plurality of optical units so that the plurality of objective lenses are disposed in close proximity to each other. An optical table fixedly supporting the actuator and the plurality of optical system units and guiding and supporting the plurality of objective lenses so as to be freely movable in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk; For the disc on which data can be recorded on both the land portion and the groove portion of the recording layer, at least a pair of the objective lenses are adjacent to each other. An optical head, characterized in that the command unit to a dedicated the groove portion controls the actuator so that data is recorded and reproduced by focusing a laser. And a plurality of lens holders for individually holding the plurality of objective lenses, a plurality of actuators for supporting the plurality of lens holders and independently driving the plurality of lens holders, and a laser light emitting / receiving unit. A plurality of optical system units for guiding the irradiated laser light to the objective lens and condensing the data on a disc to record and reproduce data on the disc, and the plurality of optical units so that the plurality of objective lenses are disposed in close proximity to each other. An optical table fixedly supporting the actuator and the plurality of optical system units and guiding and supporting the plurality of objective lenses so as to be freely movable in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk; An optical head, wherein magnetic shield means for blocking a magnetic field generated by these actuators is arranged between the plurality of actuators. 7. The optical head according to claim 6, wherein said magnetic shield means is arranged also at a position substantially symmetric about the center of said objective lens. And a plurality of lens holders for individually holding a plurality of objective lenses, a plurality of actuators for supporting the plurality of lens holders and independently driving the plurality of lens holders, and a laser light emitting / receiving unit. A plurality of optical system units for guiding the irradiated laser light to the objective lens and condensing the data on a disc to record and reproduce data on the disc, and the plurality of optical units so that the plurality of objective lenses are disposed in close proximity to each other. An optical table fixedly supporting the actuator and the plurality of optical system units and guiding and supporting the plurality of objective lenses so as to be freely movable in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk; An optical head, wherein a light shielding means for blocking laser light is arranged between the plurality of lens holders. 9. The height of the light shielding means is secured from the bottom of the optical bench to a height above a position of a rising mirror which is built in the plurality of optical system units and guides laser light perpendicular to the disk surface. The optical head according to claim 8, wherein 10. The optical head according to claim 8, wherein said light shielding means is made of a magnetic material. 11. A semiconductor device comprising: a plurality of lens holders for individually holding a plurality of objective lenses; a plurality of actuators for supporting the plurality of lens holders and independently driving each of the plurality of lens holders; A plurality of optical system units for guiding the irradiated laser light to the objective lens and condensing the data on a disc to record and reproduce data on the disc, and the plurality of optical units so that the plurality of objective lenses are disposed in close proximity to each other. An optical table fixedly supporting the actuator and the plurality of optical system units and guiding and supporting the plurality of objective lenses so as to be freely movable in a substantially radial direction between an inner peripheral portion and an outer peripheral portion of the disk; An optical head, wherein the plurality of optical system units are fixedly supported at different heights on the optical bench.