JPH05258348A - Disk and its reproducing device - Google Patents

Abstract

PURPOSE:To record information on two recording layers of a disk and to reproduce either recording layers, as well from one side surface. CONSTITUTION:A phase pit 3 and the phase pit 7 are formed on both surfaces of a transparent substrate 2 and the phase pit 3 is covered by a reflection film 5 and the phase pit 7 is covered by a protection film 9. When the information recorded on the recording layer 4 is reproduced, a laser beam focuses on the recording layer 4 by an objective lens, and when the information recorded on the recording layer 8 is reproduced, the laser beam focuses on the recording layer 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc suitable for use in, for example, an optical disc and its reproducing device, and its reproducing device.

[0002]

2. Description of the Related Art In a conventional compact disc,
Music data is recorded as phase pits on one side of the disc. On the other hand, in the optical video disc, two discs are stuck together, and the recorded information can be read out from the one surface opposite to the other surface.

[0003]

However, in the conventional optical video disc, since the two discs are stuck together, not only the disc becomes thick, but also after reproducing one side, the other side is reproduced. When doing so, it was necessary to transfer the head to the opposite side of the disk or flip the disk over. Therefore, there is a problem that the information on the two surfaces cannot be quickly reproduced.

The present invention has been made in view of the above circumstances, and it is possible to record information on substantially two layers and quickly reproduce information on any layer from one surface. It is something to do.

[0005]

A disk according to a first aspect of the present invention comprises a substrate 2 made of a light transmitting member having information recorded on one surface and the other surface, and one surface of the substrate 2. And a protective film 9 formed on the other surface of the substrate 2 and made of a member that transmits light.

According to a second aspect of the present invention, there is provided a disc reproducing apparatus for a disc 1 in which information is recorded by phase pits on the first recording layer 4 and information is recorded by hologram on the second recording layer 8A. An objective lens 11 which is a disc reproducing apparatus for reproducing and which is a light converging means for converging and irradiating light on the first recording layer 4 through the second recording layer 8A.
A photodetector 25 as a first light receiving means for receiving the reflected light from the first recording layer 4, and a second recording layer 8A.
And a photodetector 41 as a second light receiving means for receiving the reflected light from.

A disk reproducing apparatus according to a third aspect of the present invention is a disk reproducing apparatus for reproducing a disk 1 in which information is recorded by phase pits on the first recording layer 4 and the second recording layer 8. When reading the information of the first recording layer 4, the first recording layer 4 is focused and irradiated with light through the second recording layer 8, and when the information of the second recording layer 8 is read, the second recording An objective lens 11 as a light focusing means for focusing and irradiating the layer 8 with light, and a photo receiver as a light receiving means for receiving the reflected light from the first recording layer 4 or the second recording layer 8 through the objective lens 11. And a detector 25.

[0008]

In the disk according to the first aspect, information is recorded on both surfaces of the substrate 2 which transmits light. The protective film 9 is also made of a member that transmits light. Therefore,
The information on both surfaces of the substrate 2 can be reproduced through the protective film 9 and the substrate 2.

In the disc reproducing apparatus of the second aspect, the objective lens 11 focuses and irradiates the recording layer 4 with light. Then, the reflected light from the photo detector 2
The light reflected by the recording layer 8A is detected by the photodetector 41. Therefore, the record information of the recording layer 4 and the recording layer 8A can be reproduced from one side.

In the disc reproducing apparatus according to the third aspect, when reproducing the first recording layer 4, the light is focused there, and when reading information from the second recording layer 8, the light is focused there. To be done. Therefore, it is possible to reproduce either recording layer from one side.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the configuration of an embodiment of a disc and a reproducing apparatus thereof according to the present invention. In this embodiment, the substrate 2 of the disc 1 is composed of a member that transmits light. Information is recorded on both surfaces of the substrate 2 by the phase pits 3 and 7. And
A reflective film 5 made of, for example, aluminum is formed on the recording layer 4 in which the pits 3 are recorded, and a protective film 6 made of synthetic resin is further coated on the reflective film 5. On the other hand, the recording layer 8 in which the other pit 7 of the substrate 2 is formed
Is covered with a protective film 9 made of a member that transmits light.

When the recorded information is reproduced from the disc 1 as described above, it is performed as follows. That is, when reproducing the information recorded on the recording layer 4, the laser light emitted from the objective lens 11 is focused on the information recording layer 4. On the other hand, when the information recorded in the recording layer 8 is reproduced, the laser beam emitted from the objective lens 11 is recorded.
Is focused on.

That is, the laser light emitted from the laser diode 21 is collimated by the collimator lens 22 and incident on the objective lens 11 via the beam splitter 23. Then, the laser light emitted from the objective lens 11 is focused on the recording layer 4 or the recording layer 8 as described above.

The laser light reflected by the recording layer 4 or the recording layer 8 enters the beam splitter 23 via the objective lens 11. The laser light reflected by the beam splitter 23 enters a condenser lens 24 and is focused on the photodetector 25. Therefore, the photodetector 25
The information recorded in the recording layer 4 or 8 can be reproduced from the output of the.

Incidentally, when the information on the recording layer 4 is read, the laser beam is transmitted through the recording layer 8. However, this laser beam is out of focus with respect to the recording layer 8, so that it is substantially. The crosstalk component due to the recording layer 8 can be ignored. Therefore, it becomes possible to reproduce the information of the recording layer 4. Further, when the recording layer 8 is read, the laser light is focused on the recording layer 8, so that the recording layer 4 is also in the out-focus state. As a result, the proportion of the recorded information on the recording layer 4 that appears as a crosstalk component is extremely small and can be almost ignored.

The recording layer 8 needs to transmit light when the recording layer 4 is reproduced and reflect the light when the recording layer 8 is reproduced. Therefore, the recording layer 8 is processed so that light is transmitted at a predetermined rate and light is reflected at a predetermined rate.

FIG. 2 shows a second disc reproducing apparatus according to the present invention.
The example of is shown. In this embodiment, a photodetector 26 is arranged between the objective lens 11 and the beam splitter 23 outside the effective diameter of the objective lens 11. Then, when the information in the recording layers 4 and 8 is reproduced, the laser light emitted from the objective lens 11 is emitted from the recording layer 4
Is focused on. Then, the reflected light is detected by the photodetector 25 and the information of the recording layer 4 is reproduced, as in the case described above. Further, at this time, the laser light reflected from the recording layer 8 passes through the objective lens 11 and the photodetector 26.
Is incident on. The light incident on this contains almost no reflected light from the recording layer 4 (because it is eclipsed by the objective lens 11). Therefore, the information from the recording layer 8 can be reproduced from the output of the photodetector 26.

FIG. 3 shows an embodiment of a manufacturing apparatus for manufacturing the disc 1 as shown in FIGS.
As shown in the figure, a stamper 33 for the A side and a stamper 34 for the B side are prepared. Then, these stampers 33 and 34 are arranged between the fixed mold 31 and the mold moving part 32. Then, resin 36 such as acrylic is injected from the sprue 35, and the stampers 33 and 34 are injected.
Is pressed in between. This makes it possible to obtain members on which information is recorded by the phase pits on both sides of the substrate 2.
The disc 1 can be completed by forming the reflection film 5 on one surface of this member, further forming the protection film 6 on it, and forming the protection film 9 on the other surface.

On the other hand, if a stamper 34 in which information is recorded by a hologram is used as the stamper 34 in FIG. 3, as shown in FIG. 4, information is recorded by phase pits in the recording layer 4 and in the recording layer 8A. The disc 1 in which information is recorded by the hologram is obtained. When reproducing such a disc, as shown in FIG.
Thus, the laser beam is focused on the recording layer 4. Then, as in the case described above, the reflected light can be detected by the photodetector 25 via the objective lens 11, and the information recorded in the recording layer 4 can be reproduced from the detection output. On the other hand, the hologram information recorded on the recording layer 8A can be detected by the photodetector 41 arranged near the objective lens 11. That is, the laser beam emitted from the objective lens 11 is applied to the photodetector 41 by the recording layer 8.
It is reflected by A and is incident. Therefore, the information recorded in the recording layer 8A can be reproduced from the output of the photodetector 41.

The information recorded on the recording layer 4 and the recording layer 8 may be audio data or video data, for example. However, for example, although audio data and video data are recorded on the recording layer 4, the recording layer 8
Access information such as sector information, track information, chapter information of the disc 1 can be recorded in the disc.

FIG. 5 shows the construction of an embodiment of a disc reproducing apparatus when such access information is recorded on the recording layer 8 of the disc 1. The disk 1 is rotated by a spindle motor 61. A head 62 irradiates the disc 1 with light, and the information recorded therein is read by a reading circuit 65 and a processing circuit 66.
It is designed to output to. The transfer unit 64 is a CPU
Controlled by 67, the head 62 is moved in the radial direction of the disk 1. The servo circuit 63 is controlled by the CPU 67 to perform focus control, tracking control, and the like of the head 62 and drive the spindle motor 61. The operation unit 69 is operated when a predetermined command is input to the CPU 67. The ROM 68 stores programs necessary for the CPU 67 to control each unit.

Next, referring to the flow chart of FIG.
The operation will be described. First, in step S1, it is determined whether or not an access command has been input by operating the operation unit 69. If it is determined that the access command has not been input, the process proceeds to step S2, and the disc 1 is left in the stopped state.

When the operating portion 69 is operated and the CPU 67 is instructed to access the predetermined position, the process proceeds from step S1 to step S3, and the focus is controlled on the recording layer 8. That is, at this time, the CPU 67 controls the head 62 via the servo circuit 63 to generate laser light so that the laser light is focused on the recording layer 8. Further, in step S4, the head 62 reproduces the information recorded in the recording layer 8 and outputs it to the reading circuit 65. The reading circuit 65 reads this signal and outputs the reading result to the CPU 67.

As described above, access information is recorded on this recording layer 8. Then, next, in step S5, the CPU 67 compares the read access information with the access position instructed by the operation unit 69, and moves the head 62 so as to obtain the instructed access position. That is, the CPU 67 controls the head 6 via the transfer unit 64.
2 is transferred in the radial direction of the disk 1. Even during this transfer, the operation of reading the information of the recording layer 8 is repeated.

Next, in step S6, rotation of the disk is started. That is, at this time, the CPU 67 controls the spindle motor 61 via the servo circuit 63 to start the rotation of the disk 1. Next, in step S7, it is determined whether or not the number of rotations of the disk 1 is equal to or higher than a preset reference value R. The reference value R corresponds to the number of rotations at which the information recorded on the recording layer 4 can be read. When the disk rotation speed has not reached the reference value R, the process proceeds to step S8, and it is determined from the access information read from the recording layer 8 whether or not the destination has been reached. If it is determined that the destination has not been reached, the process returns to step S7.

When it is determined in step S7 that the number of rotations of the disk has reached the rotation speed at which information can be read from the recording layer 4, or in step S8.
When it is determined that the predetermined destination is reached in step S9, the process proceeds to step S9, and the head transfer started in step S5 is stopped. Then, proceeding to step S10, the CPU 67 controls the head 62 via the servo circuit 63 to switch the focus state from the recording layer 8 to the recording layer 4. Further, in step S11, it is determined whether or not the target track has been reached. This judgment is made from the address information recorded on the recording layer 4.

That is, at this time, the reading circuit 65 reads the address information from the reproduction signal output from the head 62, and the CP
It is output to U67. The CPU 67 determines the current position (more accurate position) of the head 62 from this address information. If the address information is still slightly deviated from the target track, the process proceeds to step S12, and the transfer of the head 62 (track jump) is started again. Then, returning to step S11, it is determined again whether or not the target track has been reached. In this way, the head 62 is moved from the recording layer 4 until it is determined that the target track has been reached. Then, when it is determined that the head 62 has reached the target track from the address recorded on the recording layer 4, the access is completed. At this time, the processing circuit 66 processes the output of the head 62 and outputs it to a circuit (not shown).

[0028]

As described above, according to the disk of the first aspect, information is recorded on both surfaces of the substrate made of a light transmitting member, and one surface is covered with a protective film made of a light transmitting member. Since this is done, it is possible to access information on both the one side and the other side of the substrate through this protective film.

Further, according to the disc reproducing apparatus of the second aspect, the first information is recorded by the phase pits.
Light is focused on the layer of No. 2, the information recorded there is reproduced from the reflected light, and the reflected light from the second layer that is simultaneously irradiated when the light is irradiated to the first layer is received. Since the information recorded there is reproduced, it is possible to reproduce the information from the first layer and the second layer at the same time.

According to the disc reproducing apparatus of the third aspect, when the information on the first layer and the information on the second layer are read, the focusing positions of the light are switched respectively. It becomes possible to reproduce clearly.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of an embodiment of a disc and a reproducing apparatus thereof according to the present invention.

FIG. 2 is a sectional view showing a configuration of a second embodiment of a disc reproducing apparatus of the present invention.

FIG. 3 is a cross-sectional view illustrating a method of manufacturing the disc of the present invention.

FIG. 4 is a sectional view showing the configuration of a third embodiment of the disc reproducing apparatus of the present invention.

FIG. 5 is a sectional view showing the configuration of a fourth embodiment of the disc reproducing apparatus of the present invention.

FIG. 6 is a flowchart illustrating the operation of the embodiment of FIG.

[Explanation of symbols]

 1 Disk 2 Substrate 3 Phase Pit 4 Recording Layer 6 Protective Film 7 Phase Pit 8 Recording Layer 9 Protective Film 11 Objective Lens 21 Laser Diode 25, 26, 41 Photodetector

Claims (3)

[Claims] 1. A substrate made of a light-transmissive member having information recorded on one surface and the other surface, a reflective film formed on one surface of the substrate, and the other surface of the substrate. And a protective film formed of a member that transmits light. 2. A disc reproducing apparatus for reproducing a disc in which information is recorded by phase pits in a first recording layer and information is recorded by holograms in a second recording layer, the disc reproducing device comprising: A light focusing means for focusing and irradiating light to the first recording layer through the recording layer, a first light receiving means for receiving reflected light from the first recording layer, and a second recording layer And a second light receiving means for receiving the reflected light from the disc reproducing apparatus. 3. A disc reproducing apparatus for reproducing a disc in which information is recorded by phase pits on the first recording layer and the second recording layer, wherein when the information on the first recording layer is read, Light focusing means for focusing and irradiating light on the first recording layer through the second recording layer, and focusing and irradiating light on the second recording layer when reading information on the second recording layer. And the reflected light from the first recording layer or the second recording layer,
A disc reproducing apparatus comprising: a light receiving unit that receives light through the light focusing unit.