JPH04332940A - Recording medium and optical recording/reproducing device - Google Patents

Abstract

PURPOSE:To enable information to be recorded into and reproduced from both surfaces of a magneto-optical disk. CONSTITUTION:A laser beam which is output from a laser diode 11 is separated by a beam splitter 13 and one laser beam is focused and emitted to a lower disk 1a through an objective lens 42. Also, the other laser beam is focused to an upper disk 1b through an objective lens 52. Focusing coils 43 and 53 are driven independently at movable portions 4 and 5. On the other hand tracking coils 44 and 54 and seeking coils 45 and 55 are driven by the same signal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium suitable for use in a magneto-optical disk device and an optical recording/reproducing device.

0002

2. Description of the Related Art Magneto-optical disks are being used in a variety of devices because of their large recording capacity. Although this optical disk has the advantage of a large recording capacity, it has the disadvantage that the time required for recording or reproduction is longer than that of a magnetic disk or the like. For this reason, it has been proposed, for example, to use two heads to record or reproduce signals on both sides of a magneto-optical disk.

0003

However, since the conventional apparatus operates two heads independently, it has had the problem that the configuration of the servo system is complicated. In addition, since it is not possible to accurately match each track position on one side of the magneto-optical disk to the other side, or the formation position of the servo bite where pre-pits are formed, it is virtually impossible to record on both sides at the same time. It was extremely difficult to reproduce. Furthermore, since two discs each formed to be capable of recording and reproducing independently are pasted together to form one disc, there is a problem of high cost.

[0004] The present invention has been made in view of the above situation, and it is an object of the present invention to provide a recording medium capable of high-speed recording at low cost.

Furthermore, it is an object of the present invention to provide an optical recording/reproducing device that has a simple configuration and is capable of high-speed recording.

[0006]

[Means for Solving the Problems] The recording medium according to claim 1 is a recording medium in which information is recorded on both sides, control information is recorded on one side, and information for control is recorded on the other side. It is characterized by the fact that no control information is recorded.

[0007] The optical recording/reproducing device according to claim 2 comprises:
A light source that generates recording or reproducing light; a beam splitter that splits the light output from the light source into at least two; and a beam splitter that splits one and the other of the two lights into one of the recording media. Two objective lenses that focus on one side and the other side, respectively, and the recording information is divided so that it is recorded on one side and the other side of the recording medium simultaneously, or the recorded information is reproduced from both sides of the recording medium at the same time. It is characterized by comprising a separation and synthesis circuit that synthesizes information, and a controller that controls the separation and synthesis circuit so that information is simultaneously recorded or reproduced on both sides of a recording medium.

[0008]

In the recording medium according to the first aspect, control information is recorded on one side, but no control information is recorded on the other side. Therefore, manufacturing of the recording medium becomes easy and costs can be reduced.

Further, in the optical recording/reproducing apparatus according to the second aspect of the present invention, the input recording information is separated so that it can be recorded on one side and the other side simultaneously. Alternatively, information reproduced simultaneously from both sides may be combined into one piece of information. Therefore, high-speed recording and reproduction is possible with a simple configuration.

0010

Embodiment FIG. 2 is a diagram showing the basic configuration of an optical system of an embodiment of the optical recording/reproducing apparatus of the present invention. In this embodiment, a magneto-optical disk 1 is rotated by a spindle motor 2. As shown in FIG. A head for recording and reproducing information on the magneto-optical disk 1 is composed of a fixed optical system 3 and two movable optical systems 4 and 5.

In the fixed optical system 3, the laser beam output from the laser diode 11 passes through the collimating lens 12.
The parallel light is made into parallel light and is incident on the beam splitter 13. The laser light reflected from the surface 13a of the beam splitter 13 is input to the beam splitter 22. The laser beam reflected by the surface 22a of the beam splitter 22 is emitted to the movable part 4. Conversely, the laser light incident on the fixed optical system 3 from the movable part 4 is
The light is transmitted through the surface 22a of the beam splitter 22 and is focused on the photodetector 24 via the condenser lens 23.

On the other hand, the laser beam transmitted through the surface 13a of the beam splitter 13 and reflected by the surface 13b is reflected by the surface 32a of the beam splitter 32 and output to the movable part 5. Conversely, the laser light incident on the fixed optical system 3 from the movable part 5 is transmitted through the surface 32a of the beam splitter 32, and is focused onto the photodetector 34 via the condensing lens 33.

In the movable part 4, the beam splitter 2
The laser beam incident from the magneto-optical disk 1 is reflected upward in the figure by a mirror 41, and is focused and irradiated onto the disk 1a on the lower side of the magneto-optical disk 1 by an objective lens 42. The objective lens 42 is subjected to focus control by a focusing coil 43 and tracking control by a tracking coil 44. Further, a magnetic field coil 45 applies a predetermined bias magnetic field necessary for erasing or recording. Movable part 4
has a seek coil 46 guided by a guide 47, and is movable in the radial direction of the magneto-optical disk 1.

On the other hand, the movable part 5 is also constructed in the same manner as the movable part 4. That is, the laser beam incident from the beam splitter 32 is reflected downward in the figure by the mirror 51, and is focused and irradiated onto the disk 1b above the magneto-optical disk 1 via the objective lens 52. The objective lens 52 is subjected to focus control or tracking control by a focusing coil 53 and a tracking coil 54, respectively. Further, a bias magnetic field necessary for erasing or recording is applied by a magnetic field coil 55. The movable portion 5 is movable by a coil 56 along the radial direction of the magneto-optical disk 1 against a guide 57.

FIG. 1 is a block diagram showing the electrical configuration of an embodiment of a magneto-optical disk device for recording and reproducing information using the optical system shown in FIG. A controller 61 made of, for example, a microcomputer is configured to drive the laser diode 11 via an LD drive circuit 62. It also controls the data separation circuit 63 to separate the input recording data into data to be recorded on the lower disk 1a and data to be recorded on the upper disk 1b. Data to be recorded on the lower disk is configured to drive the magnetic field coil 45 via a drive circuit 131. Further, data recorded on the upper disk 1b is supplied to the magnetic field coil 55 via the drive circuit 141.

The output of the photodetector 24 is supplied to a signal processing circuit 74, a tracking error signal generation circuit 91, and a focus error signal generation circuit 71, respectively. The output of the signal processing circuit 74 is supplied to the data synthesis circuit 64. Tracking error signal generation circuit 91
generates a tracking error signal from the input data and outputs it to the tracking servo signal generation circuit 92. The output of the tracking servo signal generation circuit 92 is supplied to the tracking coil 44 via a drive circuit 93. Further, the output of the tracking servo signal generation circuit 92 is transmitted to the drive circuit 111 for the upper disk 1b.
The signal is supplied to a tracking coil 54 via the following.

The seek servo signal generation circuit 101 is controlled by the controller 61 and generates a seek servo signal. A seek servo signal generated by the seek servo signal generation circuit 101 is supplied to the seek coil 46 via the drive signal 102 and also to the seek coil 56 via the drive circuit 121.

Furthermore, the focus error signal generation circuit 71
The focus error signal generated by the above is input to the focus servo signal generation circuit 72, and its output is supplied to the focus coil 43 via the drive circuit 73.

On the other hand, the output of the photodetector 34 is supplied to a signal processing circuit 84, subjected to signal processing, and then output to the data synthesis circuit 64.

The output of the photodetector 34 is also input to a focus error signal generation circuit 81, and the focus error signal generated there is supplied to a focus servo signal generation circuit 82. The output of the focus servo signal generation circuit 82 is supplied to the focus coil 53 via a drive circuit 83.

Next, its operation will be explained. When a recording operation is instructed, the controller 61 controls the LD drive circuit 62 to cause the laser diode 11 to emit light. As a result, as shown in FIG. 2, the laser light output from the laser diode 11 is made into parallel light by the collimator lens 12, and is incident on the beam splitter 13. The laser beam reflected on the surface 13a of the beam splitter 13 is incident on the beam splitter 22, and the laser beam reflected on the surface 22a is incident on the mirror 41 of the movable part 4. mirror 41
The laser beam reflected by the laser beam is focused and irradiated onto the lower disk 1a via the objective lens 42.

The laser beam reflected by the lower disk 1a is incident on the mirror 41 via the objective lens 42, reflected there, and incident on the beam splitter 22. The laser beam that has passed through the surface 22a of the beam splitter 22 is focused by the condensing lens 23, and is directed to the photodetector 24.
is incident on the

On the other hand, a part of the laser beam output from the laser diode 11 passes through the surface 13a of the beam splitter 13, is reflected by the surface 13b, and is further reflected by the surface 32a of the beam splitter 32, and is reflected by the mirror of the movable part 5. 51. The laser beam reflected by the mirror 51 is focused and irradiated onto the upper disk 1b via the objective lens 52.

The laser beam reflected by the disk 1b is incident on the mirror 51 via the objective lens 52, reflected there, and incident on the beam splitter 32. The laser beam transmitted through the surface 32a of the beam splitter 32 is incident on the photodetector 34 by the condensing lens 33.

As shown in FIG. 1, the output of the photodetector 24 for the lower disk 1a is input to a focus error signal generation circuit 71, where a focus error signal is generated. Although this focus error signal is omitted in FIG. 2, it can be generated by, for example, an astigmatism method. The focus error signal generated by the focus error signal generation circuit 71 is input to the focus servo signal generation circuit 72 and converted into a focus servo signal. This signal is supplied to the focus coil 43 via the drive circuit 73. As a result, the objective lens 42 is controlled to focus on the lower disk 1a.

On the other hand, the output of the photodetector 34 for the upper disk 1b is input to a focus error signal generation circuit 81, where a focus error signal is generated. The output is the focus servo signal generation circuit 82.
is supplied to and converted into a focus servo signal. This focus servo signal is supplied to the focus coil 53 via the drive circuit 83, and the objective lens 52 is controlled to focus on the upper disk 1b.

In this way, the focus servo systems of the movable parts 4 and 5 are operated independently.

On the other hand, the output of the photodetector 24 for the lower disk 1a is sent to the tracking error signal generating circuit 9.
1, and a tracking error is generated there. This tracking error signal is
For example, it can be generated by a push-pull method. This tracking error signal is input to a tracking servo signal generation circuit 92 and converted into a tracking servo signal. This tracking servo signal is further supplied to the tracking coil 44 via the drive circuit 93. Due to the stiffness, the objective lens 42 is controlled to track the track of the lower disk 1a.

Furthermore, the tracking servo signal generation circuit 9
The output of No. 2 is also supplied to the tracking coil 54 via the drive circuit 111. Therefore, the objective lens 52 is controlled to track with respect to the upper disk 1b.

On the other hand, when the controller 61 outputs a predetermined control signal to the seek servo signal generation circuit 101 so as to access a predetermined track, the seek servo signal generation circuit 101 generates a predetermined seek servo signal, and the drive circuit 102 It is supplied to the seek coil 46 via the drive circuit 121 and also to the seek coil 56 via the drive circuit 121. This controls the movable parts 4 and 5 to always access the corresponding lower and upper track positions.

When the magneto-optical disk 1 is a sample servo type disk, the lower disk 1a has a servo byte (S) for tracking and clock extraction, for example, as shown in FIG. 3(a). , control signals such as an address byte (A) indicating the address position are recorded. The tracking error signal generation circuit 91 generates a tracking error signal corresponding to the tracking prepit included in the servo byte.

On the other hand, these control signals are not recorded on the upper disk 1b, as shown in FIG. 3(b), for example. That is, as mentioned above, the upper disk 1
Tracking for b and access to a desired track position are performed dependently on the lower disk 1a. Therefore, these control signals are not required for the upper disk 1b.

Alternatively, if the magneto-optical disk 1 is a continuous servo type disk, the lower disk 1a has
For example, as shown in FIG. 4(a), a track as a pregroove is formed in advance. On the other hand, no tracks are formed on the upper disk 1b, as shown in FIG. 4(b). This is also due to the same reason as explained in FIG.

As described above, it is necessary to record predetermined control signals on one disk 1a in advance, as in the conventional case, but on the other disk 1b, these control signals must be recorded in advance. Since it is not necessary, its manufacture becomes easy. That is, it is necessary to form pre-pits or pre-grooves on the lower disk 1a, and at least form an information recording layer on the tracks thereof. On the other hand, since there is no need to form these pre-pits, tracks, etc. on the upper disk 1b, the entire surface thereof can be used as an information recording layer. Therefore, its manufacture becomes easy and the cost becomes low. By pasting these discs together, they can be used as one disc.

Now, if data a to f are serially input as recording information to the data separation circuit 63, the data separation circuit 63 separates these data into data to be recorded on the lower disk 1a and data to be recorded on the upper disk 1b. Separate the recorded data. For example, out of data a to f, a, c
, e are extracted as those recorded on the lower disk 1a, and data b, d, f are extracted as those recorded on the upper disk 1b.
Extracted as data recorded in . Then, the magnetic field coil 45 is controlled via the drive circuit 131 in accordance with the data a, c, and e. As a result, data a, c, and e are recorded on the lower disk 1a (FIG. 3(a)). On the other hand, the magnetic field coil 55 is controlled via the drive circuit 141 in accordance with data b, d, and f. As a result, data b, d,
f will be recorded (FIG. 3(b)).

Note that the clock necessary for recording is generated by the controller 61 from the output of the photodetector 24. That is,
The controller 61 extracts the clock pit included in the servo byte of the lower disk 1a, and generates a clock synchronized with this. This clock is on the lower disk 1a.
It is used not only for recording on the upper disk 1b, but also for recording on the upper disk 1b.

Next, when a reproduction operation is commanded, the controller 61 controls the data synthesis circuit 64 and the signal processing circuit 7.
The signals input from 4 and 84 are combined. That is, the signal processing circuit 74 processes the reproduced signal output from the photodetector 24 and outputs it to the data synthesis circuit 64. As a result, for example, data a, c, and e shown in FIG. 3(a) are reproduced,
The data is input to the data synthesis circuit 64. Further, the signal processing circuit 84 processes data input from the photodetector 34 and supplies the data to the data synthesis circuit 64. As a result, data b, d, f shown in FIG. 3(b), for example, are input to the data synthesis circuit 64. The data synthesis circuit 64 synthesizes these data and outputs composite data of a, b, c, d, e, and f. The clock necessary for this reproduction is also generated from the output of the photodetector 24, as in the case described above.

The magneto-optical disk 1 can be detachably attached to the spindle motor 2, but if this is done, the amount of eccentricity etc. will change each time, so it is preferable to use it as a so-called fixed disk.

[0039] In the above, the present invention has been described as an example in which the present invention is applied to a magneto-optical disk and its recording and reproducing apparatus, but the present invention can also be applied to other recording media and their recording and reproducing apparatus. .

[0040]

As described above, according to the recording medium according to claim 1, information for controlling pre-pits, tracks, etc. is recorded on one side, and no control information is recorded on the other side. This makes it possible to easily manufacture the disk and reduce costs. Furthermore, since there is no need to manage the positional relationship between one surface and the other surface when they are joined, it becomes easy to record or reproduce information on both surfaces at the same time. This enables high-speed recording and reproduction.

Further, according to the optical recording/reproducing apparatus according to claim 2, recorded information is separated into one side and the other side and recorded simultaneously, or information reproduced simultaneously from both sides is recorded. Since the images are combined, high-speed recording or playback becomes possible. Furthermore, the configuration of the servo system is simplified and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of an embodiment of the optical recording/reproducing device of the present invention.

FIG. 2 is a diagram showing the configuration of an embodiment of an optical system used in the optical recording/reproducing device of the present invention.

FIG. 3: Lower disks 1a and 1 in the embodiment of FIG. 2;
A diagram illustrating recorded information in b.

FIG. 4: Lower disks 1a and 1 in the embodiment of FIG. 2;
Diagram explaining the state of track b

[Explanation of symbols]

1 Magneto-optical disk 1a Lower disk 1b Upper disk 4, 5 Movable part 11 Laser diode 24, 34 Photodetector 42, 52 Objective lens 13 Beam splitter 61 Controller 63 Data separation circuit 64 Data synthesis circuit

Claims (2)

[Claims] 1. A recording medium in which information is recorded on both sides, wherein control information is recorded on one side and no control information is recorded on the other side. recording medium. 2. A light source that generates light for recording or reproduction, a beam splitter that splits the light output from the light source into at least two parts, and one and the other of the two lights split by the beam splitter. two objective lenses that respectively focus on one side and the other side of the recording medium, and the recording medium is divided so that the recording information is recorded on one side and the other side of the recording medium simultaneously, or the recording medium and a controller that controls the separation and synthesis circuit so that information is simultaneously recorded or reproduced on both sides of the recording medium. Optical recording and reproducing device.