JPH1011766A - Disk-like optical recording medium recording/reproducing device, and disk-like optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk-like optical recording medium recording/reproducing device capable of performing layer jump operation at a high speed. SOLUTION: When an optical disk 1 of a single side reading double layer structure is mounted, before entering reproducing operation, the eccentric amounts of a first and a second information recording layers are measured in advance, respectively, by means of a rotating angle detector 6 and a eccentricity detecting circuit 12 and the information on eccentricity is stored in a memory. At the time of layer jump during reproduction, the rotating angle of the optical disk 1 is monitored by using the rotating angle detector 6, by comparing it with the previously stored information on eccentricity in real time, jumping from the minimum eccentric position of the first information recording layer to that of the second information recording layer is performed. Consequently, jump accuracy is improved and the reproduction of a target track is quickly started.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus for a disc-shaped optical recording medium, such as a digital video disk (DVD), for recording or reproducing information recorded on a plurality of recording layers from one side, and an apparatus for this apparatus. The present invention relates to a particularly suitable disc-shaped optical recording medium.

[0002]

2. Description of the Related Art As a next generation medium of an optical disk, DV
D (Digital Video Disk).
The DVD is a large-capacity optical disk for recording data having a larger amount of information such as a digitalized video signal. The DVD employs some new technologies to increase the recording density on the optical disk as compared with the conventional technology in order to secure a large capacity. For example, the thickness of the base is 0.6 mm, and the two bases are bonded to form an optical disc having a thickness of 1.2 mm. In this case, information can be recorded on each substrate, and single-sided, two-layer reproduction can be performed.

FIG. 8 is a sectional view of an optical disc for explaining the structure of a DVD-9. In the figure, 61 is a first transparent substrate, 62 is a translucent film, 63 is a second transparent substrate, 64 is a reflective film, 65 is a transparent adhesive layer, and 66 is a pickup. This is a dual-layer single-sided optical disc that represents the structure of DVD-9 as a proposed DVD standard and can reproduce two information recording layers from one side of a substrate of the optical disc.

[0004] A pit row is formed on the upper surface of the first transparent substrate 61 and is covered with a translucent film 62. A pit row is also formed on the upper surface of the second transparent substrate 63, and is covered with the reflection film 64. The first transparent substrate 61 and the second transparent substrate 63 are bonded via a transparent adhesive layer 65. The first information recording layer (layer 0) composed of a pit row on the upper surface of the first transparent substrate 61 covered by the semi-transparent film 62 is reproduced by the pickup 66, and the second information covered by the reflection film 64 by the pickup 66 is reproduced. The second information recording layer (layer 1) composed of a pit row on the upper surface of the transparent substrate 63 is reproduced. It should be noted that one pickup is usually used as the pickup 66, and the two information recording layers are switched depending on whether the focus is adjusted to the first information recording layer (layer 0) or the second information recording layer (layer 1). Can be read.

FIG. 9 is a sectional view of an optical disk for explaining the structure of a DVD-18. In the figure, the same parts as those in FIG. 71 is a translucent film, 72 is a transparent resin layer, 73 is a reflective film, and 74 is an adhesive layer. This structure represents the structure of the DVD-18 of the proposed DVD standard, and is a two-layer double-sided optical disk.

[0006] A pit row is formed on the upper surface of the first transparent substrate 61, and is covered with a translucent film 71. A 2P (photopolymerizati) is formed on a transparent resin layer 72 formed of an ultraviolet curable resin on the translucent film 71.
The pit row is carved by using the (on) method, and is covered with the reflection film 73. The same applies to the second transparent substrate 63 side. The first transparent substrate 61 and the second transparent substrate 62
They are attached via an adhesive layer 74 with the readout surface facing outward.

A first information recording layer (layer 0) composed of a pit row on the first transparent substrate 61 covered by the semi-transparent film 71 is reproduced by the pickup 66, and is covered by the reflection film 73 by the pickup 66. Information recording layer (layer 1) composed of pit rows on the lower surface of the transparent resin layer 72
Is played. Similarly, the pickup 66 reproduces the first and second information recording layers on the second transparent substrate 63 side. In this manner, four layers are reproduced on both sides, or two layers are reproduced on one side by turning over the optical disc. In addition, as the pickup 66, one pickup is usually used for each side, and two information recordings are performed depending on which of the first information recording layer (layer 0) and the second information recording layer (layer 1) is focused. The layers can be switched and read.

[0008] Of the DVDs described above, the DVD shown in FIG.
In -9, the first information recording layer (layer 0) and the second information recording layer (layer 1) are formed on different first transparent substrates 61 and second transparent substrates 63, respectively. When bonding the first transparent substrate 61 and the second transparent substrate 63, the two substrates may be bonded with the center of the substrate shifted. In practice, it is impossible to bond with zero eccentricity, and even in each transparent substrate, there is eccentricity between the center hole and the information recording layer.

In the DVD reproducing apparatus, when chucking the optical disk to the spindle, the optical disk is positioned by the centering ring on the turntable using the center hole of the first transparent substrate 61 on the read side. Therefore, when the bonding is shifted, there is a problem that the eccentricity of the second information recording layer (layer 1) on the side of the second transparent substrate 63 opposite to the positioned substrate is increased.

On the other hand, in the DVD-18 shown in FIG. 9, a semitransparent film 71 is laminated on a base on which a first information recording layer (layer 0) is formed, and a 2P film is formed on a transparent resin layer 72 thereon.
When the second information recording layer (layer 1) is formed by the method, the center of the second information recording layer (layer 1) is shifted from the center of the track of the first information recording layer (layer 0). Since the eccentricity occurs, there is a problem that the eccentricity of the second information recording layer (layer 1) is increased as in the case of DVD-9.

According to the DVD standard, DVD-9 and DV
In both cases, the maximum eccentricity of the first information recording layer (layer 0) close to the laser light incident surface is 70 μm, and the second information recording layer (layer 1) far from the incident surface with respect to the center hole of the substrate. Is set to 100 μm. In other words, in the case of the DVD-9, the bonding of the DVD-18
When the eccentric direction is different by 180 ° between the first and second information recording layers by the 2P method, the relative maximum eccentric amount is allowed to be 100 μm + 70 μm = 170 μm. When the eccentric directions of the first and second information recording layers are the same, the relative eccentric amount is 100 μm-70 at the maximum.
It is allowed up to μm = 30 μm.

FIG. 10 is an explanatory diagram of a reproducing method of a single-sided reading dual-layer structure disk. In the figure, 81 is a first information recording layer, 82 is a second information recording layer, 83 is a lead-in area, 84 is a lead-out area, and 85 is a middle area. Single-sided, dual-layer discs are classified into two types, a parallel track path and an opposite track path, according to the reproduction method.

The optical disk of the parallel track path shown in FIG. 10A has a lead-in area 83 on the inner track and a lead-out area on the outer track of the first information recording layer 81 and the second information recording layer 82, respectively. 84, and both layers are reproduced from the inner track to the outer track.

On the other hand, the optical disc of the opposite track path shown in FIG. 10 (B) has a pair of lead-in area 83 and lead-out area 84 in the inner track, and the outer track has a middle area in each layer. 85 exist and are used for seamless reproduction. After reproducing the first information recording layer 81 from the inner track to the outer track,
When reaching the middle area 85, the second information recording layer 82
Then, the second information recording layer 82 continues the reproduction from the outer track to the inner track. Quickly move from the first information recording layer 81 to the second information recording layer 82
By performing a layer jump, continuous playback of a movie or the like can be continuously performed for a long time without interrupting the video.

The jump from the end track of the first information recording layer 81 to the start track of the second information recording layer 82 is as follows.
First, a layer jump is performed by a focus kick, and then a procedure of searching for a start track from a landing track of the second information recording layer 82 is performed. However, as described above, the first information recording layer 81 and the second information recording layer 82 have eccentricity, respectively, and thus start from the landing point of the layer jump of the second information recording layer 82. A worst case distance of 170 μm could be to the track. In this case, the seek operation must be performed to a position where the reproduction beam is present at a distance of about 230 tracks in the eccentric distance and the number of tracks.

For example, when a program such as a continuous movie is recorded from the first information recording layer 81 to the second information recording layer 82, the program is interrupted for a seek operation time. In order to ensure a seamless reproduction operation, it is necessary to store a large amount of reproduction data in a buffer memory before outputting it, and to secure data to be output during a seek operation period. Therefore,
There is a problem that it is necessary to mount a large amount of buffer memory in the reproducing apparatus in order to compensate for the time required for the seek operation.

As described in JP-A-4-243024, in a reproducing apparatus for reproducing information from a disc-shaped optical recording medium having a multi-layer information recording layer, each light spot of a plurality of light sources corresponds to the corresponding information spot. It describes that focus control is performed to match the position of the recording layer. Also,
Japanese Unexamined Patent Publication No. 5-54396 discloses a reproducing apparatus for reproducing information from a disc-shaped optical recording medium having multiple information recording layers, in which a light spot of one light source is moved to one position of an arbitrary information recording layer. A description is given of a method for performing focus control for matching. However, none of them suggests the existence of the amount of eccentricity between the information recording layers and any tracking servo technology that reduces the long seek distance caused by the amount of eccentricity between the information recording layers when switching the information recording layers. It has not been.

[0018]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has a disk-like shape capable of performing a layer jump operation from one information recording layer to another information recording layer at a high speed. An object of the present invention is to provide an optical recording medium recording / reproducing apparatus and a disc-shaped optical recording medium. For example, it is intended to ensure that seamless playback operation can be performed with a small amount of buffer memory.

[0019]

According to the first aspect of the present invention, there is provided a disc-shaped optical recording medium recording / reproducing apparatus for recording or reproducing at least one of a plurality of information recording layers from one side of a disc-shaped optical recording medium. The tracking servo means, when the information recording layer to be recorded or reproduced among the plurality of information recording layers is switched, and when the eccentricity of the information recording layer before switching is substantially zero, And turning off the tracking servo means, switching the focus to the information recording layer after the switching, and turning on the tracking servo means when the amount of eccentricity of the information recording layer after the switching is substantially zero. Things.

According to a second aspect of the present invention, in the disk-shaped optical recording medium recording / reproducing apparatus according to the first aspect, a rotational position detecting means of the disk-shaped optical recording medium and a plurality of information recording layers are provided. Eccentricity detecting means for storing eccentricity information according to the output of the rotational position detecting means when the tracking error signal of the tracking servo means is in the minimum eccentric state, and the eccentricity of the information recording layer before switching is substantially The time point at which the eccentricity of the information recording layer after switching is substantially zero is detected by detecting the time point at which the eccentricity is output from the rotational position detecting means and the eccentricity information output from the eccentricity detecting means. And the eccentricity information output from the eccentricity detecting means.

According to a third aspect of the present invention, in the disk-shaped optical recording medium recording / reproducing apparatus according to the first aspect, the rotational position detecting means for the disk-shaped optical recording medium, and Eccentricity detecting means for storing eccentricity information according to the output of the rotational position detecting means when the tracking error signal of the tracking servo means is at the minimum eccentric state, at least for each information recording layer which can be an information recording layer after switching The timing at which the amount of eccentricity of the information recording layer before switching is substantially zero is detected by the tracking error signal being in the minimum eccentric state, and the amount of eccentricity of the information recording layer after switching is substantially zero. The time point is detected by the output of the rotational position detecting means and the eccentricity information output from the eccentricity detecting means.

According to a fourth aspect of the present invention, in the disk-shaped optical recording medium recording / reproducing apparatus according to the second or third aspect, the rotation position detecting means includes an angle mark formed on the disk-shaped optical recording medium. Is detected to detect the position in the rotation direction.

According to a fifth aspect of the present invention, there is provided a disk-shaped optical recording medium having a plurality of information recording layers, wherein at least one of recording and reproduction is performed from one side. An angle mark indicating a position in the rotation direction is provided in a region near the angle mark.

[0024]

FIG. 1 is a block diagram of an optical disk reproducing apparatus according to a first embodiment of the disk-shaped optical recording medium recording / reproducing apparatus of the present invention. FIG. 2 is a plan view showing an example of the rotary encoder. In the figure, 1 is an optical disk, 2 is a spindle motor, 3 is a rotation axis, 4 is a rotary encoder, 5 is a photo detector, 6 is a rotation angle detector, 7 is a pick-up, 8 is a preamplifier, 9 is a decode signal processing circuit, 10 is A buffer memory, 11 is a servo circuit, 12 is an eccentricity detection circuit, 13 is a microprocessor, 21 is a slit, and 22 is a basic slit.

In the optical disk reproducing apparatus of this embodiment, a rotary encoder 4 and a photodetector 5 are attached to a rotating shaft 3 of a spindle motor 2 as a rotation angle detecting means. When the optical disk 1 having a single-sided reading dual-layer structure, such as a DVD-9, is mounted and before the reproduction operation is started, the rotation angle detector 6 and the eccentricity detection circuit 12 refer to FIGS. The eccentricity of the first and second information recording layers described above is measured, and the eccentricity information is stored in a RAM in the microprocessor 13 or an EPROM such as a RAM or a flash memory provided in another circuit block. .

At the time of a layer jump during reproduction of the optical recording medium, the rotation angle of the optical disc 1 is continuously monitored by using the rotation angle detector 6 and compared with the eccentricity information stored in advance in real time. Jumping from the minimum eccentric position of the first information recording layer to the minimum eccentric position of the second information recording layer. As a result, jump accuracy can be improved, and reproduction of the target track can be started quickly.

The optical disc 1 is driven by a spindle motor 2, and a rotary encoder 4 on which a slit arranged at an equal angle is recorded is attached to a rotating shaft 3. The slit is read by the photodetector 5 and output to the rotation angle detector 6 to detect the position of the optical disk in the rotation direction.

As shown in FIG. 2, a plurality of slits 21 are formed at equal angles along the outer periphery of the disk of the rotary encoder 4 as angle marks for determining the position in the rotation direction. One of the slits is a basic slit 22 provided only one per circumference. Basic slit 22
Is formed in such a manner that at least one of the shape, the reflectance and the transmittance differs from the other slits 21. For example, by increasing the width of the slit and setting the center of this width as a reference position of the rotation angle, counting the number of times of detection of the slit 21 starting from the time of detection of the basic slit 22, the rotation angle of the rotary encoder 4, that is, , Optical disk 1
Can be detected.

The slits 21 and the basic slits 22 may transmit or reflect light from a light source (not shown) at the linear portions of the slits. Black stripe printing that does not reflect light may be used. As similar to the latter, as described in JP-A-07-272394, bright and dark stripes are printed on the lower side of a turntable holding an optical disc, reflected light is detected by a photodetector, and A device for detecting a linear velocity is known, and such a turntable may be used.

Returning to FIG. 1, the description will be continued. The pickup 7 is capable of switching between the tracks on the first information recording layer and the second information recording layer of the optical disc 1 for reading, and outputs a read signal to the preamplifier 6. The pickup 7 is moved in the radial direction of the optical disc 1 by a head driving mechanism (not shown). From the preamplifier 8, a reproduced signal corresponding to the pit string pattern is output to the decode signal processing circuit 9, where decoding and other signal processing are performed, temporarily stored in the buffer memory 10, and then output. From the preamplifier 8, various detection signals for controlling the rotation speed of the spindle motor 2, controlling tracking, controlling focus, and the like are output to the servo circuit 11.

The servo circuit 11 outputs a control signal to the pickup 7 and the spindle motor 2, and also outputs a signal to the eccentricity detection circuit 12. This eccentricity detection circuit 12
Can measure the amount of eccentricity of the first information recording layer and the second information recording layer from the tracking error signal, and can detect the eccentric state of the track on the optical disc 1. The microprocessor 13 includes a servo circuit 11 and an eccentricity detection circuit 1
2, receiving signals from the rotation angle detector 6, the decode signal processing circuit 9, and controlling the decode signal processing circuit 9, the servo circuit 11, and the like.

FIG. 3 is an explanatory view of the operation of detecting the eccentric state of the first and second information recording layers in the present invention. FIG.
FIG. 3A is an explanatory view showing a slit position of the rotary encoder 4, FIG. 3B is a waveform diagram of an open tracking error signal of the first information recording layer, and FIG. 3C is a closed state of the first information recording layer. FIG. 3D is a waveform diagram of an open tracking error signal of the second information recording layer, and FIG. 3E is a waveform diagram of a closed tracking error signal of the second information recording layer. . In the figure, the same parts as those in FIG. The eccentric state can be detected by sequentially detecting the tracking error signals (TER) of the first and second information recording layers by the following two methods.

As shown in FIG. 3B, when the tracking servo is turned off, the frequency of the open tracking error signal, which is the tracking error signal detected from the first information recording layer, has a minimum eccentricity. The position becomes maximum at a certain position (zero eccentric point), becomes minimum at a position (plus eccentric point, minus eccentric point) where the eccentricity is maximum, and turns alternately. Therefore, the time when the frequency of the open tracking error signal becomes maximum is detected using a filter or the like. At this time, the photodetector 5 shown in FIG.
The slit shown in FIGS. 2 and 3A is detected, the position in the rotation direction is detected according to the position of the slit 21 from the basic slit 22, and the first information recording layer of the loaded optical disc 1 is detected. Can be determined. Subsequently, the minimum eccentric position of the second information recording layer can be determined from the open tracking error signal shown in FIG.

As shown in FIG. 3C, when the tracking servo is turned on, the closed tracking error signal, which is the tracking error signal (TER) detected from the first information recording layer, includes the optical disc 1 Is superimposed as a residual eccentric component. When the amount of eccentricity becomes zero, the closed tracking error signal crosses zero. Therefore, when the closed tracking error signal crosses zero, the slit shown in FIGS. 2 and 3A is detected, the position of the slit 21 from the basic slit 22 is detected, and the loaded optical disc 1 is detected. The minimum eccentric position of the first information recording layer can be determined. Similarly, the minimum eccentric position of the second information recording layer can be determined from the closed tracking error signal shown in FIG.

When the disc is mounted, the measured position of the minimum eccentric position of the first and second information recording layers in the rotation direction is stored in a memory as data such as a count value and an angle of the slit 21, for example. At the time of reproduction, the position of the optical disk 1 in the rotation direction is continuously monitored by using the above-described rotation angle detector 6 and compared with the minimum eccentric position stored in advance in real time. Therefore, devices such as the rotary encoder 4 and the rotation angle detector 6 need a resolution and a detection speed that can be compared in real time.

FIG. 4 is an explanatory diagram showing the layer jump operation in the present invention by the locus of the light beam spot on the disk. In the figure, 31 is a track on the first information recording layer, 32 is a track on the second information recording layer, 33 is a non-eccentric circumference, and 34 is a center point of a rotation axis. When a layer jump occurs, the information recording layer to be reproduced in the middle area shown in FIG. 10 is switched using the eccentric information such as the minimum eccentric position of the first and second information recording layers stored in the memory. . The layer jump procedure will be described with reference to the configuration diagram of FIG.

When the rotation angle detector 6 detects the minimum eccentric position A of the first information recording layer during scanning of the track 31 on the first information recording layer of the jump source, the tracking servo by the servo circuit 11 is performed. Turn off. At this time, the center position of the objective lens in the pickup 7 should be substantially at the center position of the actuator, and the trajectory of the light spot of the laser beam has a non-eccentric circumference 33 centered on the center point 34 of the rotation axis. It is above.

At this time, a method of attaching a position sensor to the actuator and forcibly holding the position of the objective lens at the center, or applying a zero voltage (G
If the lens position is locked by applying the ND voltage) and holding the objective lens at the center or the position at the time of track off, the objective lens can be more accurately positioned at the center of the actuator.

At the same time when the tracking servo is turned off, a focus kick (focus jump) is performed, and an operation of switching the focus surface from the first information recording layer to the second information recording layer is performed. Focus on Also at this time, since the optical disc 1 is rotating, the position of the light spot moves to the point B on the non-eccentric circumference 33. With the tracking servo kept off, the optical disk 1 rotates, and the position of the light spot moves on the non-eccentric circumference 33 from the point B to the point C.

When the rotation angle detector 6 detects that the position of the light spot has reached the point C which is the minimum eccentric position of the second information recording layer, the tracking servo is turned on again, and the second information recording layer is turned on. Resume playback of. As a result, when switching from the first information recording layer to the second information recording layer, since the accuracy of the layer jump is improved, the difference in the eccentricity between the first information recording layer and the second information recording layer is reduced. Due to this, the rough seek operation over several tens to several hundreds of tracks is not required, so that the target track can be reached in a short time only by the fine seek operation. Therefore, the capacity of the buffer memory required for seamless reproduction can be reduced.

FIG. 5 is an explanatory diagram showing the layer jump operation in the present invention by the signal waveform of each part. FIG. 5 (A)
5B is a focus-on signal, FIG. 5B is a focus error signal, FIG. 5C is a tracking-on signal, and FIG.
Is a tracking error signal during a layer jump operation.

FIGS. 5D through 5G are explanatory waveform diagrams for deriving the waveform diagram of FIG. 5H.
FIG. 5D shows an open tracking error signal when the tracking servo is turned off for the first information recording layer, and FIG. 5E shows a closed tracking error signal when the tracking servo is turned on for the first information recording layer. FIG. 5F is an open tracking error signal when the tracking servo of the second information recording layer is turned off.
(G) is a closed tracking error signal when the tracking servo of the second information recording layer is turned on.

During scanning of the track 31 on the first information recording layer, when the light spot reaches the minimum eccentric position A of the first information recording layer, the focus-on signal (FON) shown in FIG. ) Is temporarily turned off to perform a focus kick, and the tracking on signal (TON) shown in FIG. 5C is turned off. At this time, FIG.
The focus error signal shown in (B) is temporarily generated, but returns to zero again.

The tracking error signal shown in FIG. 5H first coincides with the closed tracking error signal of the first information recording layer shown in FIG. 5E, and the focus-on signal (FON) is turned off. When it reaches zero level,
When the focus-on signal (FON) is turned on again, it coincides with the open tracking error signal of the second information recording layer shown in FIG. When the light spot reaches point C, which is the minimum eccentric position of the second information recording layer, FIG.
When the tracking-on signal (TON) shown in FIG. 5C is turned on again, the tracking error signal shown in FIG. 5H is changed to the closed tracking error signal of the second information recording layer shown in FIG. Will be the same as

In consideration of the time required for tracking pull-in, the position where the tracking-on signal (TON) is turned on again is set to a position at a predetermined angle or a predetermined time before point C which is the minimum eccentric position. Is also good.

In the above description, the minimum eccentric position A is detected by the slit of the rotary encoder 4, and the minimum eccentric position C is similarly detected. Alternatively, the minimum eccentric position A may be detected by the zero cross point of the closed tracking signal shown in FIG. In this case, if the information recording layer before switching is always the first information recording layer, it is not necessary to detect and store the minimum eccentric position of the first information recording layer in advance. However, in the method using the closed tracking signal, in rare cases where the eccentricity is extremely small or when the pickup 7 has a wide-band slide servo that follows the eccentricity, it is difficult to detect the zero-cross point. It is desirable to use together with the angle detection method using the encoder 4 or the like.

In the above description, the minimum eccentric position is detected for both the first information recording layer and the second information recording layer, and tracking-off is performed at point A which is the minimum eccentric position of the first information recording layer. And focus kick,
Tracking-on was performed again at point C which is the minimum eccentric position of the second information recording layer. However, when the minimum eccentric position of the first and second information recording layers is detected in advance, means for determining whether the eccentric amount is smaller than a predetermined value is provided. It is possible to further shorten the layer jump.

For example, when the eccentricity of the first information recording layer is sufficiently small, the tracking off and the focus kick are immediately performed at the time of the layer jump.
Even in this case, when the amount of eccentricity of the first information recording layer is substantially zero, tracking off and focus kick are performed. Alternatively, when the amount of eccentricity of the second information recording layer is sufficiently small, tracking-on is performed again immediately after tracking-off and focus kick, for example, after completion of focus kick. Even in this case, when the eccentricity of the second information recording layer is substantially zero, the tracking is turned on again.

Further, the eccentricity component of the first information recording layer is almost determined by the eccentricity in stamper punching and the tolerance of the punched hole. At the present general technical level, the amount of eccentricity during stamper punching is 5 to 10 μm, and the tolerance of the punched hole is about 10 μm. Therefore, the amount of eccentricity of the first information recording layer is usually about 15 to 20 μm, which is relatively small. Therefore, the detection operation may be omitted for the minimum eccentric position of the first information recording layer, and a layer jump similar to the case where it is determined that the eccentric amount is sufficiently small may be performed.

FIG. 6 is a block diagram of an optical disk reproducing apparatus according to a second embodiment of the disk-shaped optical recording medium recording and reproducing apparatus of the present invention. FIG. 7 is a plan view showing an optical disc according to an embodiment of the disc-shaped optical recording medium of the present invention. In the figure, the same parts as those in FIG. 1a
Is an information recording area, 41 is a photodetector, 51 is a slit, and 52 is a basic slit. In the optical disk reproducing apparatus of this embodiment, an angle mark provided on the optical disk 1 for detecting the position in the rotation direction and the photodetector 41 are used as rotation angle detecting means.

As shown in FIG. 7, slits 51 similar to the slits 21 on the rotary encoder 4 shown in FIG. 2 are formed at regular intervals in the inner or outer peripheral area other than the information recording area 1a of the optical disk 1. In this case, one of the slits is formed with a different shape, reflectance or transmittance so as to be a basic slit 52 similar to the basic slit 22 shown in FIG.

The position of each slit is detected by the photo detector 41, and the minimum of each information recording layer detected from the tracking error signal is detected in the same manner as the slit 21 and the basic slit 22 on the rotary encoder 4 described with reference to FIG. The eccentric position is the number of slits 5 from the basic slit 52
1, it is possible to determine the minimum eccentric position of the first and second information recording layers, and to detect the timing of performing operations such as tracking off, focus kick, and tracking on.

The slits 51 and the basic slits 52 can be formed by means such as printing, vapor deposition of metal or the like, and forming irregularities when forming a substrate. Also, the optical disk 1
When cutting the master disc, the pits are formed in slits at positions corresponding to the inner or outer peripheral area other than the information recording area 1a of the optical disc 1 or the outer peripheral part in the middle area within the information recording area 1a. To form an angle mark. This is because, when cutting the portion where the slit 51 and the basic slit 52 are formed, the master of the optical disc 1 is CAV (Constant Angular).
r Velocity), and recording may be performed by turning on and off the recording laser beam so that pits are formed in slits at predetermined angular positions. With this method, an angle mark can be formed following cutting of the information recording area 1a.

Further, as a method of forming an angle mark on the optical disc 1, the reflective layer on the outer peripheral portion of the
It can also be formed by burning out into a slit shape with an AG laser or the like. The photodetector 41 detects changes in the reflectance, transmittance, and the like of the angle marks formed on the optical disk 1 as described above, and detects the angular position of the optical disk 1 in the circumferential direction.

In the above-described method of burning off the reflective layer, since the angle mark can be formed after the track is formed on the information recording layer, the first mark is used instead of the angle mark such as the slit 21 and the basic slit 22. If one angle mark is formed at the minimum eccentric position of the second information recording layer so as to be distinguishable from each other, it is not necessary for the reproducing apparatus to detect the minimum eccentric position in advance when the optical disc 1 is loaded. You can also.

When the inertia of the optical disk 1 is larger than the motor torque, the optical disk 1 may slide on a turntable or the like when the spindle motor 2 is accelerated or stopped, and the clamping angle of the optical disk 1 may be shifted. is there. In the first embodiment described with reference to FIG. 1, if the positional relationship between the optical disc 1 and the turntable changes after the mounting of the optical disc 1 due to slippage or the like, the detected eccentric position changes. When an angle mark is recorded on the optical disc 1 as in this embodiment,
It is necessary to equip the recording / reproducing device with an angle signal reading means such as the photodetector 41. However, even if the positional relationship between the optical disc 1 and the rotating shaft 3 or the turntable shifts during reproduction, the photodetector 41 constantly monitors the positions of the slit 21 and the basic slit 22 of the optical disc 1, so that the accurate minimum eccentric position Can be detected.

In the above description, a layer jump at the time of seamless reproduction has been described as an example. However, when performing a layer jump between two information recording layers other than the seamless reproduction, the information recording of the jump destination is also performed. Since the track position in the layer is not affected by the eccentricity of the information recording layer, the seek operation for searching for the next track to be recorded / reproduced can be performed in a short time.

In the above description, DVD-9, D
Since VD-18 was used as a specific example, the information recording layer had two layers and was a read-only optical disk. However, the layer jump can be performed in the same manner even when the number of layers is three or more. As a recordable multi-layer optical disk, a write-once DVD-R and an overwrite DVD-RAM using a phase change have been proposed. In these cases, a layer jump is performed in the same manner. It is possible.

[0059]

As is apparent from the above description, according to the first aspect of the present invention, the tracking servo means,
When switching the information recording layer to be recorded or reproduced from among the plurality of information recording layers, the tracking servo means is turned off when the eccentricity of the information recording layer before switching is almost zero, and after the switching, Since the control means for switching the focus to the information recording layer and turning on the tracking servo means when the eccentricity of the information recording layer after the switching is almost zero, the accuracy of the layer jump is improved. Since the seek operation over a plurality of tracks due to the difference in the amount of eccentricity between the information recording layer and the information recording layer after switching is not required, there is an effect that the target track can be reached in a short time. As a result, the time required for the layer jump is reduced, and the capacity of the buffer memory required for seamless reproduction can be reduced.

According to the second aspect of the present invention, the rotational position detecting means of the disc-shaped optical recording medium and the rotation when the tracking error signal of the tracking servo means is in the minimum eccentric state for each of a plurality of information recording layers. An eccentricity detecting means for storing eccentricity information in accordance with an output of the position detecting means, wherein a point in time when the eccentricity amount of the information recording layer before switching is substantially zero is output from the output of the rotational position detecting means and the eccentricity detecting means. The eccentricity of the information recording layer after switching is detected by the output of the rotational position detecting means and the eccentricity information output from the eccentricity detecting means. There is an effect that a point in time when the eccentricity of the recording layer and the eccentricity of the information recording layer after switching are almost zero can be easily detected.

According to the third aspect of the invention, tracking means for detecting the rotational position of the disc-shaped optical recording medium and at least one of the plurality of information recording layers which can be the information recording layer after switching is provided. Having an eccentricity detecting means for storing eccentricity information according to the output of the rotational position detecting means when the tracking error signal of the servo means is in the minimum eccentric state,
The time when the amount of eccentricity of the information recording layer before switching is almost zero,
The tracking error signal is detected by being in a minimum eccentric state, and the time when the eccentric amount of the information recording layer after switching is almost zero is detected by the output of the rotational position detecting means and the eccentric information output from the eccentric detecting means. Therefore, there is an effect that the time when the eccentricity of the information recording layer before switching and the eccentricity of the information recording layer after switching are almost zero can be easily detected.

According to the fourth aspect of the present invention, since the rotational position detecting means detects the position in the rotational direction by detecting the angle mark formed on the disc-shaped optical recording medium, the recording or reproducing operation can be performed. Even if the positional relationship between the disk-shaped optical recording medium and the rotary shaft or the turntable is deviated during acceleration or rotation stop, there is an effect that an accurate eccentric position in the rotation direction can be detected.

According to the fifth aspect of the present invention, since the outer peripheral portion and the area in the vicinity thereof have the angle mark indicating the position in the rotational direction, the disk-shaped optical recording medium which is mounted on the recording / reproducing apparatus and rotates. There is an effect that the position in the rotation direction can be accurately detected.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a recording / reproducing apparatus for a disc-shaped optical recording medium according to the present invention.
1 is a configuration diagram of an optical disc reproducing device according to an embodiment.

FIG. 2 is a plan view showing an example of a rotary encoder.

FIG. 3 is an explanatory diagram of an operation of detecting an eccentric state of first and second information recording layers in the present invention.

FIG. 4 is an explanatory diagram showing a layer jump operation in the present invention by a locus of a light beam spot on a disk.

FIG. 5 is an explanatory diagram showing a layer jump operation in the present invention by signal waveforms of respective units.

FIG. 6 shows a second embodiment of the recording / reproducing apparatus for a disc-shaped optical recording medium according to the present invention.
1 is a configuration diagram of an optical disc reproducing device according to an embodiment.

FIG. 7 is a plan view showing an optical disc according to an embodiment of the disc-shaped optical recording medium of the present invention.

FIG. 8 is a cross-sectional view of an optical disc for explaining the structure of a DVD-9.

FIG. 9 is a cross-sectional view of an optical disc for describing the structure of a DVD-18.

FIG. 10 is an explanatory diagram of a reproducing method of a single-sided reading dual-layer structure disk.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 1a ... Information recording area, 2 ... Spindle motor, 4 ... Rotary encoder, 5, 41 ... Photodetector, 6 ... Rotation angle detector, 7 ... Pick-up, 8
... Preamplifier, 11 ... Servo circuit, 12 ... Eccentricity detection circuit, 21,51 ... Slit, 22,52 ... Basic slit, 31 ... Track on first information recording layer, 32 ... Second
Tracks on the information recording layer, 33 ... non-eccentric circumference, 34
.., The center point of the rotation axis, 81: the first information recording layer, 82: the second information recording layer, 83: the lead-in area, 84: the lead-out area, 85: the middle area.

Claims (5)

[Claims] 1. A disc-shaped optical recording medium recording / reproducing apparatus for performing at least one of recording and reproduction of a plurality of information recording layers from one side of a disc-shaped optical recording medium, comprising: a tracking servo unit; When the information recording layer to be recorded or reproduced is switched, when the eccentricity of the information recording layer before switching is almost zero, the tracking servo unit is turned off and the information recording layer after switching is focused. And a control means for turning on the tracking servo means when the eccentricity of the information recording layer after switching is substantially zero. 2. The rotation position detection means for the disk-shaped optical recording medium, and the output of the rotation position detection means when a tracking error signal of the tracking servo means is in a minimum eccentric state for each of the plurality of information recording layers. Eccentricity detecting means for storing eccentricity information according to the eccentricity information output from the rotational position detecting means and the eccentricity information output from the eccentricity detecting means when the amount of eccentricity of the information recording layer before switching is substantially zero. And detecting a time point at which the eccentricity of the information recording layer after switching is substantially zero, based on an output of the rotational position detecting means and eccentricity information output from the eccentricity detecting means. 3. The recording / reproducing apparatus according to claim 1, wherein 3. A tracking error signal of the tracking servo means for each of a rotational position detecting means of the disc-shaped optical recording medium and an information recording layer which can be at least a switched information recording layer among the plurality of information recording layers. Has an eccentricity detecting means for storing eccentricity information in accordance with the output of the rotational position detecting means when the eccentricity is in the minimum eccentric state, and the tracking error is determined when the amount of eccentricity of the information recording layer before switching is substantially zero. Detected by the signal becoming the minimum eccentric state,
The time when the amount of eccentricity of the information recording layer after switching is almost zero,
The disk-shaped optical recording medium recording / reproducing apparatus according to claim 1, wherein the detection is performed based on an output of the rotational position detecting means and eccentricity information output from the eccentricity detecting means. 4. A disk according to claim 2, wherein said rotation position detection means detects a position in a rotation direction by detecting an angle mark formed on said disk-shaped optical recording medium. Optical recording medium recording and reproducing device. 5. A disk-shaped optical recording medium having a plurality of information recording layers and performing at least one of recording and reproduction from one side has an angle mark indicating a position in a rotation direction on an outer peripheral portion and a region near the outer peripheral portion. A disk-shaped optical recording medium characterized by the above-mentioned.